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. 2021 Apr 22;16(4):e0250144. doi: 10.1371/journal.pone.0250144

Disparities in smokeless tobacco use in Bangladesh, India, and Pakistan: Findings from the Global Adult Tobacco Survey, 2014-2017

Luhua Zhao 1, Lazarous Mbulo 2,*, Evelyn Twentyman 2, Krishna Palipudi 2, Brian A King 2
Editor: Pranil Man Singh Pradhan3
PMCID: PMC8062090  PMID: 33886617

Abstract

Background

Smokeless tobacco (SLT) use is associated with multiple adverse health effects. It is prominent in Bangladesh, India, and Pakistan, but disparities in use within and across these countries are not well documented or understood. This study assessed the prevalence, patterns, and correlates of SLT use in these three countries.

Method

Data came from the Global Adult Tobacco Survey, a household survey of adults aged ≥15 years. Data were collected in 2014 (Pakistan), 2017 (Bangladesh), and India (2016–2017). Current SLT use (nasal or oral use) was defined as reported SLT use daily or less than daily at the time of the survey. Prevalence of both overall and specific SLT types were assessed. Multivariate logistic regression was used to assess correlates of SLT use.

Results

Overall, SLT use among adults ≥15 years of age was 20.6% in Bangladesh, 21.4% in India, and 7.7% in Pakistan, corresponding to 22.0 million SLT users in Bangladesh, 199.4 million in India, and 9.6 million in Pakistan. Among current tobacco users overall, the percentage of those who used SLT was 58.4% (CI: 56.0–60.7) in Bangladesh, 74.7% (CI: 73.4–76.0) in India, and 40.3% (CI: 36.2–44.5) in Pakistan. The most commonly used oral SLT product was Zarda (14.5%) in Bangladesh, Khaini (11.2%) in India, and Naswar (5.1%) in Pakistan. Females had greater odds of SLT use than males in Bangladesh, but lower odds of SLT use than males in India and Pakistan. In all three countries, the odds of SLT use was higher among those 25 years and older, lower education, lower wealth index, and greater exposure to SLT marketing.

Conclusion

An estimated 231 million adults aged 15 years or older currently use SLT in Bangladesh, India, and Pakistan, comprising 40.3%-74.7% of overall tobacco product use in these countries. Moreover, marked variations in SLT use exist by population groups. Furthermore, exposure to pro-SLT marketing was found to be associated with higher SLT use compared to non-exposed. It is important that tobacco control strategies address all forms of tobacco product use, including SLT.

Introduction

Smokeless tobacco (SLT) refers to non-combustible tobacco products, excluding e-cigarettes and heated tobacco products. SLT contains nicotine, which is highly addictive. Certain SLT products have also been found to contain carcinogens [1, 2], and evidence shows that SLT use can cause oral, pharyngeal, and esophageal cancers, and other dental diseases [3, 4]. SLT use has also been associated with increased risk for cardiovascular death and stillbirth [1, 5].

Sinha et al. [6] estimated that globally, the number of deaths that could be attributed to SLT, due to all causes, was 652,494 (234,008–1,081,437). This estimate excludes Europe, where studies showed no statistically significant association between all-cause mortality and SLT use. South East Asian Region carried the major proportion (88%) of this burden [7].”

SLTs are mainly available as oral and nasal products. Oral SLT products are either chewed, sucked in the mouth, placed between the gum and the cheeks, or applied to the gums or teeth directly. Nasal SLT products are applied through the nose. SLT is often mixed with other materials to enhance flavor for the user [4, 8]. More recently, novel SLT products have entered the market, such as dissolvable tablets or sticks made from finely milled tobacco, and toothpicks with tobacco-coating [1].

Although less well characterized in the public health literature than tobacco smoking, SLT use is common in many countries. To date, there are approximately 356.4 million people that use SLT across 140 countries [9]. Based on existing data, most SLT users live in low- and middle-income countries, with 237.3 million in India (2009–2010), 30.5 million in Bangladesh (2009), and 9.7 million in Pakistan (2014) for an approximate total of 277.5 million people using SLT [9].

In these countries, SLT use is often associated with culture and beliefs. For example, SLT use is often perceived to have health benefits, is widely socially accepted, and SLT products are offered at social events where smoking may not be considered socially acceptable [2, 10, 11].

Previous studies have assessed the prevalence and patterns of SLT use in south Asian countries. Palipudi et. al. [12] reported that among adults aged 15 years or older in Bangladesh in 2009, current SLT use was 27.2%. Data from Global Adult Tobacco Survey (GATS) India 2009–2010 and GATS Pakistan 2014 also showed that among persons aged 15 years or older, current SLT use was 25.9% and 7.7%, respectively [13]. However, understanding disparities in SLT use could help inform tobacco control strategies to reduce SLT-related morbidity and mortality. Previously released results have pointed to potential sex disparities within these countries, for example, current SLT use prevalence was 16.2% for males and 24.8% for females in Bangladesh during 2017 [14], 23.4% for males, and 12.3% for females in India during 2016–2017 [15], and 11.4% for males, and 3.7% for females in Pakistan during 2014 [15]. In addition, it appears disparities may be present between urban and rural areas in India and Bangladesh but not in Pakistan [1416].

However, there are limited studies that have examined disparities in the use of specific SLT products, including disparities by demographics and socioeconomic status. In addition, there are few studies on SLT use disparities associated with exposure to SLT-specific marketing, SLT-specific warnings, or self-reported awareness of SLT harms, which could influence use of these products. Therefore, this study analyzed the most recent GATS data from Bangladesh, India, and Pakistan to assess the prevalence, patterns, and disparities of SLT use, including concurrent and exclusive use of various types of SLT products, as well as correlates of SLT use, in each of these three countries.

Methods

Data source

This study utilized GATS data from Bangladesh, India, and Pakistan. In all three countries, GATS was implemented as a nationally representative, household-based, cross-sectional survey of non-institutionalized adults aged 15 years or older, which uses a standardized sample design, survey protocols, and questionnaire to ensure data comparability [17]. GATS was conducted in Bangladesh in 2017 with 14,880 completed individual interviews for a 90.8 overall response rate; India in 2016–2017 with 74,037completed individual interviews for a 92.9% overall response rate, and Pakistan in 2014 with 7,831 completed individual interviews for an overall response rate of 81.0%.

Measures

Tobacco product use

Current SLT use was defined with the question, “Do you currently use smokeless tobacco on a daily basis, less than daily, or not at all. Smokeless tobacco include zarda, sada pata, gul, khoinee, nosshil (Bangladesh); tobacco leaf, betel quid with tobacco, sada/surti, khaini or tobacco lime mixture, gutkha, pan masala with zarda, mawa, gul, gudaku, mishri (India); and naswar, nass (sniffed in the nose), paan with tobacco, gutka, mainpuri and others (Pakistan)”. Using this question, we develop a new “current SLT use” variable consisting of individuals using SLT daily and less than daily.

Current tobacco smoking was defined with the question, “Do you currently smoke tobacco on a daily basis, less than daily, or not at all?” Using the question, we develop a new “current tobacco smoking” variable consisting of individuals who smoke tobacco on a daily and less than daily basis.

Current tobacco use was defined using the definition advanced by Kar, Sivanantham, Chinnakali, and Thiagarajan [18]: “Do you currently smoke tobacco?” and “Do you currently use smokeless tobacco?” Those who responded as “daily” and “less than daily” to both or either one of the questions, were defined as “current tobacco user” and those who responded, “not at all” were defined as “current tobacco nonuser” [18].

The use of specific SLT products was assessed using the following questions: ‘On average, how many times a day (for daily users)/a week (for less than daily users) do you use the following product: [insert product name]?’ SLT product types included in the questions are listed for all three countries in Table 2.

Table 2. Prevalence of current smokeless tobacco use overall and by type among adults aged 15+ by in Bangladesh, India and Pakistan, GATS 2014–2017.
Bangladesh India Pakistan
Type Percent (CI 95%) Type Percent (CI 95%) Type Percent (CI 95%)
Total Overall SLT 20.6 (19.4, 21.9) 21.4 (20.7, 22.1) 7.7 (6.6, 8.8)
Nasal Nasal Nasal
 N/A - -  Nasal use of snuff 0.5 (0.4, 0.6)  Naas (sniffed in the nose) 0.4 (0.2, 0.6)
Oral Oral Oral
 Koinee 0.1 (0.0, 0.2)  Khaini or tobacco lime mixture 11.2 (10.7, 11.7)  Naswar 5.1 (4.3, 5.9)
 Pan Masala with tobacco 0.8 (0.6, 1.2)  Paan masala with tobacco 2.8 (2.6, 3.1)  Paan with tobacco 1.5 (1.1, 2.0)
 Gul 3.6 (3.1, 4.3)  Gutka, areca nut-tobacco lime mixture, or Mawa 6.8 (6.4, 7.3)  Gutka 0.8 (0.5, 1.4)
 Sada pata chewing 0.7 (0.4, 1.0)  Oral tobacco use (as mishri, qul, or gudakhu) 3.8 (3.5, 4.1)  Mainpuri 0.4 (0.1, 0.9)
 Betel quid with Sada pata 5.5 (4.8, 6.3)  Betal quid with tobacco 5.8 (5.4, 6.2)
 Betel quid with Zarda, Zarda only, or Zarda with Supari 14.5 (13.5, 15.6)
Other unspecified SLT 0.1 (0.0, 0.4) Other unspecified SLT 0.3 (0.2, 0.3) Other unspecified SLT 0.2 (0.1, 0.3)
Male Overall SLT 16.2 (14.8, 17.7) 29.6 (28.7, 30.6) 11.4 (9.7, 13.4)
Nasal Nasal Nasal
 N/A - -  Nasal use of snuff 0.7 (0.5, 0.9)  Naas (sniffed in the nose) 0.2 (0.1, 0.4)
Oral Oral Oral
 Koinee 0.1 (0.0, 0.3)  Khaini or tobacco lime mixture 17.9 (17.0, 18.7)  Naswar 8.4 (7.0, 9.9)
 Pan Masala with tobacco 0.3 (0.2, 0.5)  Paan masala with tobacco 4.5 (4.0, 5.0)  Paan with tobacco 1.7 (1.1, 2.7)
 Gul 3.1 (2.4, 4.0)  Gutka, areca nut-tobacco lime mixture, or Mawa 10.8 (10.1, 11.5)  Gutka 1.3 (0.8, 2.0)
 Sada pata chewing 0.3 (0.1, 0.7)  Oral tobacco use (as mishri, qul, or gudakhu) 3.3 (3.0, 3.7)  Mainpuri 0.5 (0.2, 1.4)
 Betel quid with Sada pata 2.3 (1.8, 3.0)  Betal quid with tobacco 7.1 (6.5, 7.7)
 Betel quid with Zarda, Zarda only, or Zarda with Supari 13.0 (11.7, 14.3)
Other unspecified SLT 0.0 N/A Other unspecified SLT 0.3 (0.2, 0.4) Other unspecified SLT 0.3 (0.2, 0.6)
Female Overall SLT 24.8 (23.0, 26.6) 12.8 (12.0, 13.5) 3.7 (2.9, 4.8)
Nasal Nasal Nasal
 N/A - -  Nasal use of snuff 0.6 (0.5, 0.7)  Naas (sniffed in the nose) 0.6 (0.3, 1.0)
Oral Oral Oral
 Koinee 0.0 (0.0, 0.1)  Khaini or tobacco lime mixture 4.2 (3.8, 4.6)  Naswar 1.7 (1.2, 2.3)
 Pan Masala with tobacco 1.3 (0.8, 2.1)  Paan masala with tobacco 1.1 (0.9, 1.3)  Paan with tobacco 1.2 (0.8, 1.9)
 Gul 4.1 (3.4, 5.0)  Gutka, areca nut-tobacco lime mixture, or Mawa 2.7 (2.3, 3.1)  Gutka 0.3 (0.1, 1.1)
 Sada pata chewing 1.0 (0.6, 1.7)  Oral tobacco use (as mishri, qul, or gudakhu) 4.3 (3.9, 4.8)  Mainpuri 0.2 (0.1, 0.4)
 Betel quid with Sada pata 8.5 (7.3, 9.8)  Betal quid with tobacco 4.5 (4.0, 5.0)
 Betel quid with Zarda, Zarda only, or Zarda with Supari 16.0 (14.6, 17.6)
Other unspecified SLT 0.1 (0.0, 0.7) Other unspecified SLT 0.3 (0.2, 0.4) Other unspecified SLT 0.0 (0.0, 0.1)

N/A: Not available; -: Data not available. SLT: Smokeless tobacco. CI: Confidence Interval.

Current use of oral SLT was defined as a positive response to any of the SLT products other than ‘Nasal use of snuff’ in India and ‘Naas’ in Pakistan. Bangladesh did not collect information on nasal forms of SLT use.

Demographic characteristics and socioeconomic status

Assessed demographic characteristics included: sex, urbanicity, age, and educational attainment. A wealth index was constructed as a proxy measure of socio-economic status using information on household ownership of certain common household items such as electricity, flush toilet, fixed telephone, cell telephone, television, radio, refrigerator, car, moped/scooter/motorcycle, and washing machine [19]. The wealth index was divided into wealth index quintile rankings as follows: lowest, low, middle, high, and highest [19].

Awareness of SLT harms

A respondent was considered aware of the harms of SLT if they answered “yes” to the question, “Based on what you know or believe, does using smokeless tobacco cause serious illness?”.

Exposure to anti-SLT messages

A respondent was considered to be exposed to an anti-SLT message if they answered “yes” to any of the following questions: “in the past 30 days, have you noticed any information in [insert media type] about the dangers of use or that encourages quitting of smokeless tobacco products”. The types of media that were assessed across countries were: newspapers, magazines, television, radio, and billboards/hoardings; additionally, the Bangladesh survey included posters, and India included cinemas, the internet, public transportation vehicles, railways or bus stations, and public walls.

Exposure to SLT marketing

A respondent was considered to be exposed to SLT marketing if they answered “yes” to any of the questions that measured whether in the past 30 days the respondents noticed SLT advertisements and promotions in different venues. The assessed avenues included: stores where the products are sold, television, radio, billboards, posters, newspapers, magazines, cinemas, internet, public transportation vehicles or stations, and public walls.

Analysis

Descriptive statistics, including point estimates and 95% confidence intervals (CI), were calculated for current SLT use, both overall and by SLT product type. Prevalence of current SLT use was calculated by selected sociodemographic characteristics. Differences between two estimates that are not independent of each other (e.g. prevalence of tobacco smoking vs. prevalence of SLT use given that a person can use both products) were tested using methods introduced by Wild and Seber [20], a variation of a normal test that takes into account overlapping cases and produces more precise variance. Estimates by sex and urbanicity were compared using Chi-square tests. Cochran–Mantel–Haenszel tests for trend were used to test for trends across age, education, and wealth index. T-tests were used for all other comparisons. For all analyses, p-values less than 0.05 were considered statistically significant.

Multivariate logistic regression was conducted to examine correlates of current SLT use; adjusted odds ratios (aOR) and corresponding 95% CI were calculated. Assessed correlates included: sex, urbanicity, age group, education, wealth index, current tobacco smoking status, awareness of SLT harms, exposure to anti-SLT messages, and exposure to SLT marketing.

SAS (Ver. 9.4) was used for data management and SAS-Callable SUDAAN (Ver. 11.0) was used for analyses in order to control for the complex survey design of GATS. Following GATS weighting protocol, all data were weighted to the estimated national target population in each respective country [21].

Results

Smokeless tobacco use–overall and by sex

Overall, prevalence of current SLT use was 20.6% (CI: 19.4–21.9) in Bangladesh, 21.4% (CI: 20.7–22.1) in India, and 7.7% (CI: 6.6–8.8) in Pakistan (Table 1). These prevalence estimates correspond to 22.0 (CI: 20.7–23.4) million current SLT users in Bangladesh, 199.4 (CI: 191.6–207.2) million in India, and 9.6 (CI: 8.2–10.9) million in Pakistan.

Table 1. Sample size, prevalence and type of tobacco used overall and by sex among adults aged 15 years or older in Bangladesh, India and Pakistan, GATS 2014–2017.

Bangladesh (2017) India (2016–17) Pakistan (2014)
Unweighted n Weighted Percent (95% CI) Unweighted n Weighted Percent (95% CI) Unweighted n Weighted Percent (95% CI)
Total
Current Tobacco User 12783 35.3 (33.9, 36.7) 74037 28.6 (27.9, 29.3) 7790 19.1 (17.4, 20.9)
 Current Tobacco Smoker 12783 18.0 (17.0, 19.0)* 74037 10.7 (10.2, 11.1)* 7831 12.4 (11.2, 13.8)*
 Current Smokeless Tobacco User 12783 20.6 (19.4, 21.9) 74037 21.4 (20.7, 22.1) 7780 7.7 (6.6, 8.8)
  Nasal - - 74037 0.5 (0.4, 0.6) 7780 0.4 (0.2, 0.6)
  Oral 12783 20.6 (19.4, 21.9) 74037 21.0 (20.3, 21.7) 7781 7.3 (6.3, 8.5)
Current Smokeless Tobacco User among Current Tobacco Users 5128 58.4 (56.0, 60.7) 21857 74.7 (73.4, 76.0) 1548 40.3 (36.2, 44.5)
Weighted number of SLT users (million) 12783 22.0 (20.7, 23.4) 74037 199.4 (191.6, 207.2) 7780 9.6 (8.2, 10.9)
Male
Current Tobacco User 6079 46.0 (43.9, 48.0) 33772 42.4 (41.3, 43.5) 3769 31.8 (28.8, 34.9)
 Current Tobacco Smoker 6079 36.2 (34.2, 38.2)** 33772 19.0 (18.2, 19.9)** 3782 22.2 (19.8, 24.8)**
 Current Smokeless Tobacco User 6079 16.2 (14.8, 17.7) 33772 29.6 (28.7, 30.6) 3759 11.4 (9.7, 13.4)
  Nasal - - 33772 0.6 (0.4, 0.7) 3759 0.2 (0.1, 0.4)
  Oral 6079 16.2 (14.8, 17.7) 33772 29.4 (28.4, 30.4) 3760 11.2 (9.5, 13.2)
Current Smokeless Tobacco User among Current Tobacco Users 3155 35.2 (32.5, 38.1) 15576 69.9 (68.5, 71.3) 1310 36.1 (31.8, 40.6)
Weighted Smokeless Tobacco users (million) 6079 8.4 (7.7, 9.2) 33772 141.2 (135.5, 146.8) 3759 7.3 (6.1, 8.4)
Female
Current Tobacco User 6704 25.2 (23.4, 27.1) 40265 14.2 (13.5, 15.0) 4021 5.8 (4.7, 7.0)
 Current Tobacco Smoker 6704 0.8 (0.5, 1.2) 40265 2.0 (1.7, 2.3) 4049 2.1 (1.6, 2.9)
 Current Smokeless Tobacco User 6704 24.8 (23.0, 26.6) 40265 12.8 (12.0, 13.5) 4021 3.7 (2.9, 4.8)
  Nasal - - 40265 0.5 (0.4, 0.6) 4021 0.6 (0.3, 1.0)
  Oral 6704 24.8 (23.0, 26.6) 40265 12.3 (11.5, 13.0) 4021 3.2 (2.4, 4.3)
Current Smokeless Tobacco User among Current Tobacco Users 1973 98.3 (97.1, 99.0) 6281 89.8 (88.1, 91.2) 238 64.4 (55.0, 72.7)
Weighted Smokeless Tobacco users (million) 6704 13.6 (12.6, 14.6) 40265 58.2 (54.5, 61.9) 4021 2.3 (1.7, 2.8)

Current tobacco smokers refer to those who reported smoking tobacco products daily or less than daily; Current smokeless Tobacco users refer to those who reported using smokeless tobacco products daily or less than daily. Current tobacco users refer to those were either a current tobacco smoker or current smokeless tobacco user. -: Not available; N: Sample size; CI: Confidence interval.

* Wild & Seber tests p<0.05 compared to that of SLT use from the same country.

** t-tests p<0.05 compared to that of females from the same country.

SLT use was statistically significantly higher (p<0.05) among females compared to males in Bangladesh (females, 24.8% CI: 23.0–26.6; males, 16.2% CI: 14.8–17.7), while current SLT use was significantly lower (p<0.05) in females than males in both India (12.8% CI: 12.0–13.5 vs. 29.6% CI: 28.7–30.6) and Pakistan (3.7% CI: 2.9–4.8 vs. 11.4% CI: 9.7–13.4).

The prevalence of current SLT use was significantly higher (p<0.05) than tobacco smoking in Bangladesh (20.6%; CI: 19.4–21.9 vs. 18.0%; CI: 17.0–19.0, respectively) and India (21.4%; CI: 20.7–22.1 vs. 10.7 CI: 10.2–11.1, respectively); in contrast, it was lower in Pakistan (7.7%; CI: 6.6–8.8 vs. 12.4%; CI: 11.2–13.8, respectively).

Among current tobacco users overall, the percentage of those who used SLT was 58.4% (CI: 56.0–60.7) in Bangladesh, 74.7% (CI: 73.4–76.0) in India, and 40.3% (CI: 36.2–44.5) in Pakistan (Table 1). In Bangladesh, 35.2% (CI: 32.5–38.1) of male current tobacco users were SLT users compared to 98.3% (CI: 97.1–99.0) of females. In India, the percentage was 69.9% (CI: 68.5–71.3) for males and 89.8% (CI:88.1–91.2) for females. In Pakistan, it was 36.1% (CI: 31.8–40.6) for males and 64.4% (CI: 55.0–72.7) for females.

Smokeless tobacco use—by product type

The two most commonly used oral SLT types in Bangladesh were: betel quid with zarda, zarda only, or zarda with supari only (14.5%; CI: 13.5–15.6); and betel quid with sada pata only (5.5%; CI: 4.8–6.3). In India, the two most commonly used SLT types were: khaini only (11.2%; CI: 10.7–11.7); and gutka, areca nut-tobacco lime mixture, or mawa (6.8%; CI: 6.4–7.3). The two most commonly used SLT types in Pakistan were naswar only (5.1%; CI: 4.3–5.9); and paan with tobacco only (1.5%; CI: 1.1–2.0) (Fig 1).

Fig 1. Distribution of various smokeless tobacco products among current smokeless tobacco user in Bangladesh, India and Pakistan, GAT 2014–2017.

Fig 1

Prevalence of nasal SLT use was 0.5% (CI: 0.4–0.6%) in India and 0.4% (CI: 0.2–0.6%) in Pakistan (Table 2). Bangladesh did not collect information on nasal SLT use.

Smokeless tobacco use—by selected demographic and socioeconomic characteristics

Urban/rural

In Bangladesh, current SLT use was 22.5% (CI: 21.0–24.1) in rural areas compared to 14.9% (CI: 13.2–16.8) in urban areas. In India, it was 24.6% (CI: 23.8–25.4) in rural areas compared to 15.2% (CI:14.0–16.5) in urban areas. In Pakistan, it was 8.2% (CI: 6.7–10.1) in rural areas compared to 6.7% (CI: 5.6–7.9) in urban areas (Table 3). Prevalence of current SLT use was higher among rural residents than urban residents in Bangladesh and India (both p<0.05); no statistically significant difference was observed in Pakistan.

Table 3. Prevalence and adjusted odds ratios of current smokeless tobacco use among adults aged 15 years or older by selected demographic and socioeconomic characteristics in Bangladesh, India and Pakistan, GATS 2014–2017.
Bangladesh India Pakistan
N Percent (95% CI) aOR (95% CI) N Percent (95% CI) aOR (95% CI) N Percent (95% CI) aOR (95% CI)
Overall 12783 20.6 (19.4, 21.9) - 74037 21.4 (20.7, 22.1) - 7780 7.7 (6.6, 8.8) -
Sex Male 6079 16.2 (14.8, 17.7) REF 33772 29.6 (28.7, 30.6) REF 3759 11.4 (9.7, 13.4) REF
Female 6704 24.8 (23.0, 26.6) # 1.53 (1.31, 1.80) * 40265 12.8 (12.0, 13.5) # 0.26 (0.24, 0.28) * 4021 3.7 (2.9, 4.8) # 0.20 (0.14, 0.28) *
Urbanicity Urban 6356 14.9 (13.2, 16.8) REF 26488 15.2 (14.0, 16.5) $ REF 3770 6.7 (5.6, 7.9) REF
Rural 6427 22.5 (21.0, 24.1)# 1.15 (0.96, 1.37) 47549 24.6 (23.8, 25.4)# 1.18 (1.05, 1.32) * 4010 8.2 (6.7, 10.1) 0.84 (0.61, 1.15)
Age group 15–24 2345 4.0 (3.1, 5.1) $ REF 13329 10.8 (10.0, 11.8) $ REF 2095 3.4 (2.2, 5.2) $ REF
25–34 3363 14.5 (12.9, 16.3) 3.53 (2.69, 4.64)* 18600 21.2 (20.1, 22.3) 2.29 (2.04, 2.56)* 2015 8.5 (6.5, 10.9) 3.13 (1.88, 5.21)*
35–44 3034 23.2 (20.8, 25.8) 5.93 (4.46, 7.88)* 16964 25.7 (24.4, 27.0) 2.85 (2.51, 3.24)* 1658 8.2 (6.5, 10.3) 2.99 (1.72, 5.18)*
45–54 2088 36.4 (33.1, 39.9) 10.35 (7.73, 13.86)* 11501 27.0 (25.6, 28.6) 3.03 (2.62, 3.50)* 955 10.4 (8.5, 12.7) 4.36 (2.50, 7.57)*
55–64 1124 41.5 (37.4, 45.7) 12.52 (9.20, 17.04)* 7631 27.3 (25.7, 28.9) 2.78 (2.38, 3.24)* 602 15.9 (11.9, 21.0) 5.68 (2.92, 11.03)*
65+ 829 47.1 (42.1, 52.3) 15.10 (10.75, 21.21)* 6012 29.6 (27.6, 31.7) 3.08 (2.62, 3.62)* 455 8.8 (5.8, 13.0) 3.38 (1.65, 6.94)*
Education No formal education 3581 39.7 (37.1, 42.3) $ REF 18473 28.9 (27.7, 30.1) $ REF 3597 10.1 (8.4, 12.0) $ REF
Less than primary 2057 24.2 (21.8, 26.7) 0.78 (0.65, 0.93) * 7510 30.7 (29.0, 32.5) 0.92 (0.83, 1.02) 393 10.6 (6.6, 16.5) 1.10 (0.60, 2.03)
Primary completed 1573 16.2 (13.8, 19.0) 0.59 (0.48, 0.73) * 8858 26.8 (25.3, 28.4) 0.84 (0.75, 0.93) * 806 7.6 (5.3, 10.6) 0.79 (0.53, 1.18)
Less than secondary 2710 10.7 (9.3, 12.3) 0.45 (0.36, 0.56) * 12109 22.3 (20.9, 23.7) 0.75 (0.67, 0.83) * 739 8.6 (5.7, 12.7) 0.94 (0.56, 1.59)
Secondary/high school completed 2059 6.1 (4.7, 7.9) 0.32 (0.23, 0.44) * 18290 13.1 (12.2, 14.1) 0.46 (0.41, 0.52) * 1633 3.5 (2.6, 4.8) 0.43 (0.29, 0.64) *
College and above 803 5.9 (3.7, 9.3) 0.23 (0.14, 0.39) * 8738 7.5 (6.5, 8.6) 0.27 (0.23, 0.33) * 611 2.2 (1.1, 4.5) 0.26 (0.11, 0.61) *
Wealth index Lowest 2561 31.4 (29.0, 34.0) $ REF 15547 33.0 (31.6, 34.4) $ REF 1469 13.3 (9.7, 17.9) $ REF
Low 2585 22.6 (20.5, 25.0) 0.71 (0.59, 0.85) * 18685 24.5 (23.4, 25.7) 0.69 (0.63, 0.76) * 1690 10.5 (8.3, 13.3) 0.63 (0.42, 0.93) *
Medium 2525 20.7 (18.4, 23.2) 0.75 (0.62, 0.91) * 11278 20.5 (19.1, 22.0) 0.59 (0.52, 0.66) * 1559 6.6 (5.1, 8.5) 0.56 (0.34, 0.91) *
High 2571 17.0 (14.8, 19.4) 0.63 (0.50, 0.78) * 14814 13.9 (12.9, 15.1) 0.42 (0.37, 0.48) * 1064 7.4 (5.2, 10.2) 0.63 (0.36, 1.10)
Highest 2541 10.8 (8.8, 13.2) 0.44 (0.33, 0.58) * 13713 7.3 (6.5, 8.3) 0.25 (0.21, 0.30) * 1998 3.0 (2.1, 4.3) 0.23 (0.12, 0.41) *
Current tobacco smoking status Yes 2493 18.3 (16.1, 20.8) 0.65 (0.54, 0.80) * 9499 32.3 (30.3, 34.3) 0.73 (0.65, 0.82) * 953 8.2 (5.7, 11.6) 0.39 (0.24, 0.65) *
No 10290 21.1 (19.8, 22.5) REF 64538 20.1 (19.4, 20.8) # REF 6827 7.6 (6.5, 8.8) REF
Awareness of SLT harm Yes 12178 20.4 (19.2, 21.8) 1.05 (0.77, 1.43) 70798 21.0 (20.3, 21.7) 0.80 (0.69, 0.91)* 5923 7.5 (6.5, 8.8) 1.00 (0.74, 1.37)
No 602 23.6 (18.8, 29.1) REF 3221 29.5 (27.0, 32.2) # REF 1802 8.0 (6.4, 10.0) REF
Exposure to anti-SLT messages Yes 4240 20.8 (18.6, 23.1) 1.46 (1.24, 1.71) * 48588 20.0 (19.2, 20.8) 1.00 (0.92, 1.09) 1242 5.4 (3.9, 7.5) 0.61 (0.40, 0.95) *
No 8492 20.4 (19.1, 21.8) REF 25414 24.3 (23.2, 25.4) # REF 6168 8.1 (7.0, 9.5) REF
Exposure to SLT marketing Yes 1006 28.4 (24.2, 33.0) 1.78 (1.43, 2.23) * 13507 25.3 (23.8, 27.0) 1.49 (1.35, 1.65) * 906 13.6 (10.6, 17.4) 2.17 (1.57, 3.00) *
No 11770 20.0 (18.8, 21.2) # REF 60411 20.4 (19.7, 21.1) # REF 6172 6.8 (5.7, 8.0) # REF

REF: Reference group. aOR: Adjusted odds ratio. CI: Confidence Interval. aOR and CI for aOR retain two decimals for greater precision.

* p value for Wald F test <0.05 from logistic regression.

# Chi square tests p<0.05.

$ Cochran-Mantel-Haenszel tests for trend p<0.05. SLT: Smokeless tobacco.

Age

Across all three countries, SLT use prevalence generally increased with increasing age (p<0.05). This disparity was particularly prominent in Bangladesh, where prevalence ranged from 4.0% (CI: 3.1–5.1) for those aged 15–24 years to 47.1% (CI: 42.1–52.3) for those aged 65+ years. In India, prevalence ranged from 10.8% (CI: 10.0–11.8) for those aged 15–24 years to 29.6% (CI: 27.6–31.7) for those aged 65+ years. In Pakistan, prevalence ranged from 3.4% (CI: 2.2–5.2) for those aged 15–24 years to 15.9% (CI: 11.9–21.0) for those aged 55–65 years.

Education

The prevalence of current SLT use decreased as education attainment increased in Bangladesh, India, and Pakistan (p<0.05). In Bangladesh, the prevalence ranged from 39.7% (CI:37.1–42.3) among those with no formal education to 5.9% (CI: 3.7–9.3) among those with college education or above (Table 3). In India, the prevalence ranged from 30.7% (CI: 29.0–32.5) among those with less than primary education to 7.5% (CI: 6.5–8.6) among those with college education or above. In Pakistan, the prevalence ranged from 10.6% (CI: 6.6–16.5) among those with less than primary school education, to 2.2% (CI: 1.1–4.5%) among those with college education or above.

Wealth index

The prevalence of current SLT use decreased as the wealth index increased in Bangladesh, India, and Pakistan (p<0.05) (Table 3). In Bangladesh, the prevalence ranged from 31.4% (CI: 29.0–34.0) among those in the lowest wealth index, to 10.8% (CI: 8.8–13.2) among those in the highest wealth index. In India, prevalence by wealth index ranged from 33.0% (CI: 31.6–34.4) among those in the lowest wealth index, to 7.3% (CI: 6.5–8.3) among those in the highest wealth index. In Pakistan, the respective prevalence ranged from 13.3% (CI: 9.7–17.9) among those in the lowest wealth index, to 3.0% (CI: 2.1–4.3) among those in the highest wealth index.

Other tobacco product use

Current tobacco smokers had higher prevalence of SLT use compared to non-smokers (32.3%; CI: 30.3–34.3 vs. 20.1%; CI: 19.4–20.8, p<0.05) in India, but not in Bangladesh (18.3%; CI: 16.1–20.8 vs. 21.1%; CI: 19.8–22.5), and Pakistan (8.2%; CI: 5.7–11.6 vs. 7.6%; CI: 6.5–8.8).

Knowledge of SLT harms

In India, those who were aware of SLT harms had lower prevalence of SLT use compared to those who were not aware (21.0%; CI: 20.3–21.7 vs. 29.5%; CI: 27.0–32.2. p<0.05), but not in Bangladesh (20.4%; CI: 19.2–21.8 vs. 23.6%; CI: 18.8–29.1), and Pakistan (7.5%; CI: 6.5–8.8 vs. 8.0%; CI: 6.4–10.0).

Pro and anti SLT messaging

In India, those who were exposed in the past 30 days to anti-SLT use messages had lower SLT prevalence compared to those who were not exposed (20.0%; CI: 19.2–20.8%) vs. 24.3%; CI: 23.2–25.4%) (P<0.05) but not in Bangladesh (20.8%; CI: 18.6–23.1) vs. 20.4%; CI: 19.1–21.8)) and Pakistan (5.4%; CI: 3.9–7.5%) vs. 8.1%; CI: 7.0–9.5%).

In all three countries, those who were exposed in the past 30 days to pro-SLT marketing had higher SLT use prevalence compared to those who were not exposed (p<0.05). The prevalence for Bangladesh was 28.4% (CI:24.2–33.0%) for those exposed compared to 20.0% (CI: 18.8–21.2%) for those not exposed. In India, prevalence was 25.3% (23.8–27.0) compared to 20.4% (CI: 19.7–21.1%). In Pakistan, prevalence was 13.6% (CI: 10.6–17.4%) compared to 6.8% (CI: 5.7–8.0%).

Multivariate analyses

The odds of SLT use was higher among females than males in Bangladesh (aOR: 1.53; CI: 1.31–1.80), but lower in females than males in India (aOR: 0.26; CI: 0.24–0.28) and Pakistan (aOR: 0.20; CI: 0.14–0.28). Compared to those aged 15–24 years, the odds of SLT use in Bangladesh was higher among those aged 25–45 years (aOR: 4.30; CI: 3.34–5.62), 45–65 years (aOR: 9.80; CI: 7.40–12.86), and 65+ years (aOR: 12.80; CI 9.15–17.96). In India, compared to those aged 15–24 years, the odds of SLT use was higher among those aged 25–45 years (aOR: 2.40; CI: 2.19–2.73), 45–65 years (aOR: 2.70; CI: 2.33–3.04), and 65+ years (aOR: 2.8 (2.36–3.24). In Pakistan, compared to those aged 15–24 years, the odds of SLT use was higher among those aged 25–45 years (aOR: 2.40; CI: 1.47–3.76), 45–65 years (aOR: 3.70; CI: 2.23–6.20), and 65+ years (aOR: 2.20, CI: 1.15–4.19).

In Bangladesh, compared to those with no formal education, the odds of SLT use were lower among those with less than primary (aOR: 0.78; CI 0.65–0.93), primary completed (aOR: 0.59; CI: 0.48–0.73), less than secondary (aOR: 0.45; CI:0.36–0.56), secondary/high school complete (aOR:0.32; CI: 0.23–0.44), and college and above (aOR: 0.23; CI: 0.14–0.39). In India, compared to those with no formal education, the odds of SLT use were lower among those with primary completed (aOR: 0.84; CI: 0.75–0.93), less than secondary (aOR: 0.75; CI:0.67–0.83), secondary/high school complete (aOR:0.46; CI: 0.41–0.52), and those with college and above (aOR: 0.27; CI: 0.23–0.33). In Pakistan, compared to those with no formal education, the odds of SLT use were lower among those with secondary/high school complete (aOR:0.43; CI: 0.29–0.64), and those with college and above (aOR: 0.26; CI: 0.11–0.61).

Those ranked in the highest wealth index in all three countries had lower odds of SLT use compared to those in the lowest wealth index. In Bangladesh, compared to the lowest wealth index, the odds of SLT use were lower among those in the low (aOR:0.71; CI: 0.59–0.85), medium (aOR: 0.75; CI:0.62–0.91), high (aOR: 0.63: CI: 0.50–0.78), and highest (aOR: 0.44; CI: 0.33–0.58) wealth indices. In India, compared to the lowest wealth index, the odds of SLT use were lower among those in the low (aOR:0.69; CI: 0.63–0.76), medium (aOR: 0.59; CI: 0.52–0.66), high (aOR: 0.42: CI: 0.37–0.48), and highest (aOR: 0.25; CI: 0.21–0.30) wealth indices. In Pakistan, compared to the lowest wealth index, the odds of SLT use were lower among those in the low (aOR: 0.63; CI: 0.42–0.93), medium (aOR: 0.56; CI: 0.34–0.91), and highest (aOR: 0.3; CI: 0.15–0.55) wealth indices.

In all three countries, the odds of SLT use were lower among current tobacco smokers compared to non-tobacco smokers. Compared to non-tobacco smokers, the odds of SLT use among current tobacco smokers was lower in Bangladesh (aOR: 0.65; CI: 0.54–0.80), India (aOR: 0.73; CI: 0.65–0.82), and Pakistan (aOR: 0.39; (0.24–0.65).

In Bangladesh, the odds of SLT use were higher among those exposed to anti-SLT messages in the past 30 days compared to those not exposed (aOR: 1.46; CI: 1.24–1.71); in India, no significant association between exposure to anti-SLT messages in the past 30 days and SLT use were observed; and in Pakistan, the odds of SLT use were lower among those exposed to anti-SLT messages in the past 30 days compared to those not exposed (aOR: 0.61; CI: 0.40–0.95). Awareness of SLT harms was only significant (p<0.05) in India, where the odds of STL use among those aware of the harms of SLT use was higher compared to those not aware (aOR: 0.80; CI: 0.69–0.91).

Discussion

The findings from this study reveal that current SLT use comprises a large portion of overall tobacco use in the assessed countries, including nearly 6 in 10 persons who currently use tobacco in Bangladesh, more than 7 in 10 in India, and about 4 in 10 in Pakistan. Across all three countries, current SLT use was higher among the 25 years and older age groups, particularly in Bangladesh and India. Additionally, all three countries showed a marked socio-demographic and economic disparity in SLT use defined by sex, education, wealth index, and age. Specifically, adults with lower education levels, and adults with lower wealth index had significantly higher odds of current SLT use. These findings are consistent with those in other studies, where use of SLT was high among those with low SES [12, 22, 23]. It is therefore important that these underlying socio-demographic, economic, and/or environmental disadvantages are considered when implementing SLT prevention and reduction strategies.

The challenge to addressing tobacco use among low SES population in Bangladesh, India, and Pakistan may also need to address the existence of tax evasion, illicit sales and production of smokeless tobacco including illicit trade and low levels of taxation for these products [11, 24]. This illegal supply chain provide affordable and accessible SLT products that sustains the consumption of these products among the low SES population. Addressing this problem could help in restricting availability and affordability of SLT products to low SES population and young people critical to preventing and reducing consumption.

In addition, the study found socio-demographic differences in current SLT use by sex that were apparent in each country. Females had lower odds of current SLT use in India and Pakistan compared to males, but higher odds in Bangladesh. This finding is consistent with a previous study in Bangladesh [25] and cross-country sex differences may be the result of variations in social acceptability of tobacco product use [2, 3, 26]. This suggest the need for SLT use prevention and cessation strategies to take into consideration historical, social, and cultural acceptance of SLT use in all three countries, even among females, that might also be driving some of the observed disparities [23]. Another consideration is that the odds of current SLT use was lower among current tobacco smokers compared to non-tobacco smokers. Thus, Bangladesh, India, and Pakistan could consider addressing SLT use separately in tobacco control efforts given that the economic and health effects of SLT use are different from that of smoking [24] in most low-resource and high SLT burden Parties has been reported in the MPOWER 2017, which is required to be strengthene.

Furthermore, our results showed that exposure to pro-SLT marketing was associated with higher SLT use compared to non-exposed. As parties to WHO Framework Convention on Tobacco Control (FCTC), all three countries have at various levels implemented bans on tobacco advertising, promotion and sponsorship (FCTC Article 13) particularly a ban on product display which, is main advertisement tool for point-of-sale vendors [27, 28]. India has passed comprehensive ban on advertising, promotion, and sponsorship of all tobacco products including SLT [28]. Bangladesh made amendment to Tobacco Control Law in 2013 to require graphic health warnings to cover 50% of SLT packaging, ban on advertisement of SLT products, and restriction to sale to minors [11]. Pakistan has also passed legislations on tobacco control that could indirectly affect SLT production, sale, promotion, and consumption. However, a lack of specific wordings in the legislations in Pakistan for SLT, raise challenges with enforcement of the law [28]. In all three countries, there are difficulties in enforcement of the law banning SLT promotion and sponsorship [11, 28].

Finally, this study confirms that the majority of SLT products consumed in all three countries were in oral form and shows that use of nasal tobacco is relatively low in both India and Pakistan [1]. Although some SLT products are common (e.g. gul or gutka) in Bangladesh, India, and Pakistan, the most commonly used products differed in these three countries [1]. This suggests the importance of addressing the significant heterogeneity of SLT products and their toxic constituents and additives, and evidence-based strategies for SLT use prevention and control. Such strategies could include SLT product surveillance and monitoring, establishing effective and relevant health warning labels on SLT products, and cessation support [1]. Given a positive association was found for exposure to anti-SLT messages and SLT use in Bangladesh, this result may suggest ongoing review and updating of public health messaging campaigns around SLT. Other interventions may include establishing standards for toxicants and maximum pH levels, effective health warning labels, increasing prices on SLT products, prohibiting SLT promotion, sponsorship, or marketing [1].

This study is subject to some limitations. First, data were self-reported, which could introduce recall biases or underestimates of SLT use due to social desirability biases. However, GATS use a standardized global protocol to produce nationally representative estimates with measures that are comparable across countries [21]. Second, although all three countries used the same protocol and questions, there are variations in data collection time across the countries that might warrant caution in cross-country comparisons. Finally, we used the wealth index as a proxy for socio-economic status. However, the wealth index is considered an accepted proxy for socio-economic status in household surveys [29].

Conclusion

SLT use comprises the most tobacco use in Bangladesh (58.4%), and India (74.7%), and a large portion of tobacco use in Pakistan (40.3%), with clear disparities in use by socio-demographic and economic characteristics in these countries. Importantly, SLT use remain a major public health challenge in the three countries and other South and Southeast Asian countries which, suggests a need to prioritize SLT in tobacco control efforts [23]. It may be beneficial to focus STL use prevention and control interventions at populations with high STL use prevalence such as older adults, those with lower education, and those in the lower wealth quintile. In addition, all three countries may need to focus on SLT use among females as majority of females who used tobacco were using SLT. Finally, our findings demonstrate that opportunities exist to improve anti-SLT messaging, reduce exposure to SLT marketing, and protecting populations with a higher prevalence of SLT use in these countries.

Acknowledgments

Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the U.S. Centers for Disease Control and Prevention.

Data Availability

All data files are available from the GTSSdata base at https://www.cdc.gov/tobacco/global/gtss/gtssdata/index.html.

Funding Statement

Partial funding for the Global Adult Tobacco Survey (GATS) in Bangladesh, India, and Pakistan was provided by the Bloomberg Initiative to Reduce Tobacco Use through the CDC Foundation with a grant from Bloomberg Philanthropies.

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Decision Letter 0

Pranil Man Singh Pradhan

10 Feb 2021

PONE-D-21-01174

Disparities in Smokeless Tobacco Use in Bangladesh, India, and Pakistan: Findings from the Global Adult Tobacco Survey, 2014 -2017

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Additional Editor Comments:

Production, import and sale of illicit smokeless tobacco products are also contributory factors fueling the SLT epidemic in these countries. Although the objectives of this study does not directly relate to it, it would be worthwhile to mention this in the discussion.

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Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: Yes

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Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Dear authors,

It was an interesting read. however going through the article I found some issues.

Introduction:

• In line 71 and 73 the disease burden due to SLT use is explained in DALYs lost. It is confusing as one DALY means a year of healthy life lost. For eg: disease burden due to SLT use was 8,691,827 disability-71 adjusted life years (DALYs) and 72 348,798 deaths sounds appropriate to me.

• In line 98 author have said no literature have examined disparities in SLT use however in a paragraph just above in line 93 to 97 have presented the findings from GATS survey which have found different disparities in SLT use.

• The authors have said that the study analyzed the data from GATS survey and assessed the prevalence

Methodology:

• The authors have stated using the data from GATS survey at different time period in three south Asian countries. In line 111 the sample size and response rate of the study was according to the GATS survey itself, or authors identified is confusing to understand. The data collection method is not clear, how the data were extracted for analysis and presentation needs a clearer explanation.

• Different measures are explained as means of data collection but were these measures an operational definition from GATS survey or authors of the study created it? If it is from GATS survey than it is to be explained as the measures taken in survey to generate data in different variables were: - OR if it came from author of this article it should explain on more how data are presented in GATS survey and how authors generated required data from survey findings.

• In line 134 the author have said to use quartile rankings to divide wealth index and only divided in only 3 groups, moreover later in results have presented 5 categories in wealth index.

Result:

• The tables are difficult to understand as there may be mathematical issues just for instance the in table 1 out of 12783 participants 35.3 % are current tobacco user which comes to be around 4513, however while presenting the data of current smokeless tobacco user among current tobacco user the total number given is 5128 which comes to be around 40.1% of 12783 beyond the CI presented before.

Discussion:

• No findings or comparisons from other studies are represented showing lack of coherence.

Reviewer #2: The topic of the study is very interesting and the researchers seems to have put a lot of work into it. The overall idea is very good and explores an important issue in public health. However, I believe there are corrections that need to be made so that the manuscript comes out better. The suggestions are as follows:

1. General Comment:

-There are some inconsistencies in language in some places, please proof read the document again.

2. Introduction:

-It seems inappropriate to keep information from GATS 2014 of Pakistan and GATS 2017 of Bangladesh in the ‘Introduction section’. As you have included both of these surveys in your analysis and included sex and age as the factors while assessing disparities in SLT, this information is appropriate for the ‘Result section’.

3. Methodology:

- While giving operational definitions, there are repetitions in some places. Please try and remedy this.

4. Results:

-Adjusted Odd’s ratio(AOR) is mentioned only for some variables. In order to maintain consistency, it may be better to mention the AOR for all the variables mentioned in the writing of results section.

-Statistical tests that have been used are not very clear in the tables.

5. References:

-Some references do not seem to follow the journal guidelines. Please make needed correction.

**********

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Reviewer #1: Yes: Mukesh Poudel

Reviewer #2: No

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PLoS One. 2021 Apr 22;16(4):e0250144. doi: 10.1371/journal.pone.0250144.r002

Author response to Decision Letter 0


28 Feb 2021

EDITOR COMMENTS

Comment 1: Production, import and sale of illicit smokeless tobacco products are also contributory factors fueling the SLT epidemic in these countries. Although the objectives of this study does not directly relate to it, it would be worthwhile to mention this in the discussion.

Response to Comment 1: We have incorporated this in our discussion section. which reads as follows (See page 5): “The challenge to addressing tobacco use among low SES populations in Bangladesh, India, and Pakistan may also need to address the existence of tax evasion, illicit sales, and production of smokeless tobacco, including illicit trade and low levels of taxation for these products (11, 24). This illicit supply chain provides more affordable and accessible SLT products, which can sustain the consumption of these products among individuals with lower SES. Addressing these issues could help diminish the extent to which critical populations initiate and use these products, including those with low SES population and young people.”

REVIEWER 1

Comment 1: In line 71 and 73 the disease burden due to SLT use is explained in DALYs lost. It is confusing as one DALY means a year of healthy life lost. For eg: disease burden due to SLT use was 8,691,827 disability-71 adjusted life years (DALYs) and 72 348,798 deaths sounds appropriate to me.

Response to Comment 1: We have revised this section and now reads as follows (See page X): “Sinha et al. (6) estimated that globally, the number of deaths that could be attributed to SLT, due to all causes, was 652,494 (234,008–1,081,437). This estimate excludes Europe, where studies showed no statistically significant association between all-cause mortality and SLT use. South East Asian Region carried the major proportion (88%) of this burden (6).”

Comment 2: In line 98 author have said no literature have examined disparities in SLT use however in a paragraph just above in line 93 to 97 have presented the findings from GATS survey which have found different disparities in SLT use.

Response to Comment 2: We revised to reads as follows (see page X): “However, there are limited studies that have examined disparities in the use of specific SLT products, including disparities by demographics and socioeconomic status. In addition, there are few studies on SLT use disparities associated with exposure to SLT-specific marketing, SLT-specific warnings, or self-reported awareness of SLT harms, which could influence use of these products.”

Comment 3: The authors have stated using the data from GATS survey at different time period in three south Asian countries. In line 111 the sample size and response rate of the study was according to the GATS survey itself, or authors identified is confusing to understand. The data collection method is not clear, how the data were extracted for analysis and presentation needs a clearer explanation.

Response to Comment 3: The text has been revised as follows (See page 4): “This study utilized GATS data from Bangladesh, India, and Pakistan. In all three countries, GATS was implemented as a nationally representative, household-based, cross-sectional survey of non-institutionalized adults aged 15 years or older, which uses a standardized sample design, survey protocols, and questionnaire to ensure data comparability (17). GATS was conducted in Bangladesh in 2017 with 14,880 completed individual interviews for a 90.8 overall response rate; India in 2016-2017 with 74,037completed individual interviews for a 92.9% overall response rate, and Pakistan in 2014 with 7,831 completed individual interviews for an overall response rate of 81.0%.

Comment 4: Different measures are explained as means of data collection but were these measures an operational definition from GATS survey or authors of the study created it? If it is from GATS survey than it is to be explained as the measures taken in survey to generate data in different variables were: - OR if it came from author of this article it should explain on more how data are presented in GATS survey and how authors generated required data from survey findings.

Response to Comment 4: The manuscript has been revised as follows (see page 5):

Tobacco Product Use

Current SLT use was defined with the question, “Do you currently use smokeless tobacco on a daily basis, less than daily, or not at all. Smokeless tobacco include zarda, sada pata, gul, khoinee, nosshil (Bangladesh); tobacco leaf, betel quid with tobacco, sada/surti, khaini or tobacco lime mixture, gutkha, pan masala with zarda, mawa, gul, gudaku, mishri (India); and naswar, nass (sniffed in the nose), paan with tobacco, gutka, mainpuri and others (Pakistan)”. Using this question, we develop a new “current SLT use” variable consisting of individuals using SLT daily and less than daily.

Current tobacco smoking was defined with the question, “Do you currently smoke tobacco on a daily basis, less than daily, or not at all?” Using the question, we develop a new “current tobacco smoking” variable consisting of individuals who smoke tobacco on a daily and less than daily basis.

Current tobacco use was defined using the definition advanced by Kar, Sivanantham, Chinnakali, and Thiagarajan (18): “Do you currently smoke tobacco?” and “Do you currently use smokeless tobacco?” Those who responded as “daily” and “less than daily” to both or either one of the questions, were defined as “current tobacco user” and those who responded, “not at all” were defined as “current tobacco nonuser” (18).

Comment 5: In line 134 the author have said to use quartile rankings to divide wealth index and only divided in only 3 groups, moreover later in results have presented 5 categories in wealth index.

Response to Comment 5: We have revised the manuscript as follows (see page 6): “The wealth index was divided into wealth index quintile rankings as follows: lowest, low, middle, high, and highest (19).”

Comment 6: The tables are difficult to understand as there may be mathematical issues just for instance the in table 1 out of 12783 participants 35.3 % are current tobacco user which comes to be around 4513, however while presenting the data of current smokeless tobacco user among current tobacco user the total number given is 5128 which comes to be around 40.1% of 12783 beyond the CI presented before.

Response to Comment 6: We verified the numbers in the tables, and they are correct. We have also clarified the labeling in table 1. Specifically, the N (sample size) revised to “n” is unweighted and the Percent (95% CI) are weighted estimates. Thus, the number of respondents (unweighted n) multiplied by the weighted percent of current tobacco users would not be expected to align. This approach is commonly used in the literature, and thus, have retained this presentation of the results.

However, to help further clarify this issue for the reviewer, we have provided the below table presenting unweighted and weighted estimates.

Current smokeless tobacco users among tobacco users - GATS Bangladesh 2017

Unweighted percent1 Unweighted number Weighted percent Weighted number2

Total (Tobacco users) 100 5,128 100 37,761,628

Current smokeless tobacco users 60.82 3,119 58.38 22,047,040

Non-current smokeless tobacco users 39.18 2,009 41.62 15,714,588

Comment 7: Discussion: No findings or comparisons from other studies are represented showing lack of coherence.

Response to Comment 7: We have added comparison and reference to other studies in the discussion and now reads as follows (see page 14): “Additionally, all three countries showed a marked socio-demographic and economic disparity in SLT use defined by sex, education, wealth index, and age. Specifically, adults with lower education levels, and adults with lower wealth index had significantly higher odds of current SLT use. These findings are consistent with those in other studies, where use of SLT was high among those with low SES(12, 22, 23).”

REVIEWER 2

Comment 1: General Comment: There are some inconsistencies in language in some places, please proof read the document again.

Response to Comment 1: We have reviewed, edited, and proofed the manuscript to remove inconsistences.

Comment 2: Introduction: It seems inappropriate to keep information from GATS 2014 of Pakistan and GATS 2017 of Bangladesh in the ‘Introduction section’. As you have included both of these surveys in your analysis and included sex and age as the factors while assessing disparities in SLT, this information is appropriate for the ‘Result section’.

Response to Comment 2: We present the previously published findings from GATS Pakistan (2014) and GATS Bangladesh (2017) to provide background, and to reinforce the gaps in the scientific literature filled by the present study. Since these estimates were conducted and published elsewhere in the scientific literature, we do not feel it is appropriate to cite these data in our own Results. Instead, we duly acknowledge these data in the Introduction, while using it as a foundation to reinforce the objective of the present study, which provides further detail on this data source and the presented measures.

Comment 3: Methodology: While giving operational definitions, there are repetitions in some places. Please try and remedy this.

Response to Comment 3: We have revised the operational definitions to address the repetitions, which now reads as follows (See page 5):

Tobacco Product Use

Current SLT use was defined with the question, “Do you currently use smokeless tobacco on a daily basis, less than daily, or not at all. Smokeless tobacco include zarda, sada pata, gul, khoinee, nosshil (Bangladesh); tobacco leaf, betel quid with tobacco, sada/surti, khaini or tobacco lime mixture, gutkha, pan masala with zarda, mawa, gul, gudaku, mishri (India); and naswar, nass (sniffed in the nose), paan with tobacco, gutka, mainpuri and others (Pakistan)”. Using this question, we develop a new “current SLT use” variable consisting of individuals using SLT daily and less than daily.

Current tobacco smoking was defined with the question, “Do you currently smoke tobacco on a daily basis, less than daily, or not at all?” Using the question, we have developed a new “current tobacco smoking” variable consisting of individuals who smoke tobacco on a daily and less than daily basis.

Current tobacco use was defined using the definition advanced by Kar, Sivanantham, Chinnakali, and Thiagarajan (18): “Do you currently smoke tobacco?” and “Do you currently use smokeless tobacco?” Those who responded as “daily” and “less than daily” to both or either one of the questions, were defined as “current tobacco user” and those who responded, “not at all” were defined as “current tobacco nonuser” (18).

Comment 4: Results: Adjusted Odd’s ratio(AOR) is mentioned only for some variables. In order to maintain consistency, it may be better to mention the AOR for all the variables mentioned in the writing of results section.

Response to Comment 4: We have updated the results section to include aOR for all the variables mentioned in the writing of results section. The section reads as follows (see page 12-13):

Multivariate Analyses

The odds of SLT use was higher among females than males in Bangladesh (aOR: 1.53; CI: 1.31-1.80), but lower in females than males in India (aOR: 0.26; CI: 0.24-0.28) and Pakistan (aOR: 0.20; CI: 0.14-0.28). Compared to those aged 15-24 years, the odds of SLT use in Bangladesh was higher among those aged 25-45 years (aOR: 4.30; CI: 3.34-5.62), 45-65 years (aOR: 9.80; CI: 7.40-12.86), and 65+ years (aOR: 12.80 (9.15-17.96). In India, compared to those aged 15-24 years, the odds of SLT use was higher among those aged 25-45 years (aOR: 2.40; CI: 2.19-2.73), 45-65 years (aOR: 2.70; CI: 2.33-3.04), and 65+ years (aOR: 2.8 (2.36-3.24). In Pakistan, compared to those aged 15-24 years, the odds of SLT use was higher among those aged 25-45 years (aOR: 2.40; CI: 1.47-3.76), 45-65 years (aOR: 3.70; CI: 2.23-6.20), and 65+ years (aOR: 2.20, CI: 1.15-4.19).

In Bangladesh, compared to those with no formal education, the odds of SLT use were lower among those with less than primary aOR: 0.78; CI 0.65-0.93), primary completed (aOR: 0.59; CI: 0.48-0.73), less than secondary (aOR: 0.45; CI:0.36-0.56), secondary/high school complete (aOR:0.32; CI: 0.23-0.44), and college and above (aOR: 0.23; CI: 0.14-0.39). In India, compared to those with no formal education , the odds of SLT use were lower among those with primary completed (aOR: 0.84; CI: 0.75-0.93), less than secondary (aOR: 0.75; CI:0.67-0.83), secondary/high school complete (aOR:0.46; CI: 0.41-0.52), and those with college and above (aOR: 0.27; CI: 0.23-0.33). In Pakistan, compared to those with no formal education, the odds of SLT use were lower among those with secondary/high school complete (aOR:0.43; CI: 0.29-0.64), and those with college and above (aOR: 0.26; CI: 0.11-0.61).

Those ranked in the highest wealth index in all three countries had lower odds of SLT use compared to those in the lowest wealth index. In Bangladesh, compared to the lowest wealth index, the odds of SLT use were lower among those in the low (aOR:0.71; CI: 0.59-0.85), medium (aOR: 0.75; CI:0.62-0.91), high (aOR: 0.63: CI: 0.50-0.78), and highest (aOR: 0.44; CI: 0.33-0.58) wealth indices. In India, compared to the lowest wealth index, the odds of SLT use were lower among those in the low (aOR:0.69; CI: 0.63-0.76), medium (aOR: 0.59; CI: 0.52-0.66), high (aOR: 0.42: CI: 0.37-0.48), and highest (aOR: 0.25; CI: 0.21-0.30) wealth indices. In Pakistan, compared to the lowest wealth index, the odds of SLT use were lower among those in the low (aOR: 0.63; CI: 0.42-0.93), medium (aOR: 0.56; CI: 0.34-0.91), and highest (aOR: 0.3; CI: 0.15-0.55) wealth indices.

In all three countries, the odds of SLT use were lower among current tobacco smokers compared to non-tobacco smokers. Compared to non-tobacco smokers, the odds of SLT use among current tobacco smokers was lower in Bangladesh (aOR: 0.65; CI: 0.54-0.80), India (aOR: 0.73; CI: 0.65-0.82), and Pakistan (aOR: 0.39; (0.24-0.65).

Comment 5: Statistical tests that have been used are not very clear in the tables.

Response to Comment 5: The statistical tests are specified in the footnotes for the tables.

In Table 1, the statistical test footnotes are: * Wild & Seber tests p<0.05 compared to that of SLT use from the same country; and ** t-tests p<0.05 Compared to that of females from the same country.

In Table 2, the statistical tests presented in the footnotes are: REF: Reference group. aOR: Adjusted odds ratio. CI: Confidence Interval. * p value for Wald F test p<0.05 from logistic regression. # Chi square tests p<0.05.$ Cochran-Mantel-Haenszel tests for trend p<0.05. SLT: Smokeless tobacco

Comment 6: References: Some references do not seem to follow the journal guidelines. Please make needed correction.

Response to Comment 6: We have revised the references according to Plos One guidelines.

Attachment

Submitted filename: Authors Response to Reviewers Comments and Suggestions.docx

Decision Letter 1

Pranil Man Singh Pradhan

1 Apr 2021

Disparities in Smokeless Tobacco Use in Bangladesh, India, and Pakistan: Findings from the Global Adult Tobacco Survey, 2014 -2017

PONE-D-21-01174R1

Dear Dr. Mbulo,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Pranil Man Singh Pradhan

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: (No Response)

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: (No Response)

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Dear Authors.

The paper was interesting to go through. I somewhere found different grammatical issues, so may need a review again before publishing. The abbrevations used are somewhere SLT and somewhere STL, is it same or different.

Reviewer #2: I agree with your replies to most of my previous comments. However, I am still unconvinced about your reply to comment 2 and comment 5

Regarding comment 2: I still stand by my previous comment.

Regarding comment 5: In Table 1, I can appreciate that the tests have been indicated. However, as there are many variables in the table. It is confusing which variables are being assessed by the statistical tests.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Mukesh Poudel

Reviewer #2: No

Acceptance letter

Pranil Man Singh Pradhan

12 Apr 2021

PONE-D-21-01174R1

Disparities in Smokeless Tobacco Use in Bangladesh, India, and Pakistan: Findings from the Global Adult Tobacco Survey, 2014 -2017

Dear Dr. Mbulo:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Pranil Man Singh Pradhan

Academic Editor

PLOS ONE


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