Abstract
INTRODUCTION
Approximately 70% of Chinese adults are exposed to secondhand smoke (SHS) each week and 100 000 people die from SHS every year in China. This study evaluates associations between the belief that SHS causes serious illness and intention to quit, attempts to quit, and quitting smoking, among Chinese adult smokers.
METHODS
A nationally representative sample of 4866 current and former adult smokers in the Global Adult Tobacco Survey was used for analysis. Multivariable weighted regression models were built to determine significant associations between smoking cessation behavior and the belief that SHS causes serious illness.
RESULTS
The belief that SHS causes serious illness was associated with intention to quit (AOR 1.62, 95% CI: 1.24, 2.12) and quitting smoking (AOR 1.44, 95% CI: 1.15, 1.81). Other variables associated with smoking cessation behavior included not permitting smoking at home (intending: AOR 1.59, 95% CI: 1.10, 2.31; attempting: AOR 1.73, 95% CI: 1.25, 2.40; quitting: AOR 2.71, 95% CI: 1.90, 3.89) and the belief that smoking causes serious illness (attempting: AOR 1.63, 95% CI: 1.14, 2.33; quitting: AOR 1.66, 95% CI: 1.21, 2.28).
CONCLUSIONS
These results indicate that believing SHS causes serious illness may play a role in quitting smoking. In China’s collectivistic culture, interventions should focus on how SHS exposure affects the health of friends and family. This message can be combined with other proven tobacco control methods such as: smoking bans in public places, warning labels on cigarette packages, high cigarette taxes, and mass media campaigns to reduce tobacco use.
Keywords: smoking cessation, secondhand smoke, China
INTRODUCTION
China is the world’s largest producer, manufacturer, and consumer of tobacco1,2. Chinese men consume over one-third of the world’s cigarettes3,4. The prevalence of smoking in China among people 15 years or older was 28.1% in 2010, including 52.9% of men and 2.4% of women2. Although the quit rate has increased from 3% in 1991 to 9% in 2006, one-third of male smokers will eventually die from tobacco-related disease3.
Each year, exposure to secondhand smoke (SHS) causes over 435 000 adult and 165 000 childhood deaths globally5. Worldwide, 40% of children, 35% of women, and 33% of men are exposed to SHS indoors5. Adverse health outcomes including ischemic heart disease, lower respiratory infections, asthma, and lung cancer may be reduced with interventions limiting SHS exposure5.
Belief that SHS causes serious illness, and that it is associated with smoking behavior, has been studied extensively in Western nations6,7. The belief that SHS causes illness, particularly in children, is positively associated with quit attempts among smokers6,7. In Australia, one in five smokers attempted to quit due to concerns that their behavior was causing problems among friends and family6.
There is less information in China about the associations between adults’ belief that SHS causes serious illness, and behavioral intention to quit, attempts to quit, and quitting smoking. Approximately 70% of adults are exposed to SHS each week and 100 000 people die from SHS every year in China8. Of all Chinese adults, 54.3% reported being exposed to SHS at work, 76.3% at restaurants, and 16.4% on public transportation9. Lower levels of income and education are associated with higher exposure to SHS in China10.
Positive associations were demonstrated between the awareness of personal health risks of smoking, and quit-smoking behavior11,12. Results from China’s International Tobacco Control survey indicate pressure from friends and family motivate Chinese adults to attempt to quit smoking11,12. Health concerns for oneself and one’s family were also cited as a primary reason for attempting to quit smoking in a study of male smokers in Hangzhou13. It is unclear, however, whether personal health concerns or SHS were the primary motivator for attempting to quit. It remains to be determined whether knowledge that SHS can harm friends and family has an impact on successfully quitting smoking. Described herein is a cross-sectional study of current Chinese smokers, age 15 years and older, surveyed in 2010, to evaluate the associations between the belief that SHS causes serious illness and intention to quit, attempts to quit, and quitting smoking tobacco.
METHODS
Questionnaire
The World Health Organization (WHO) and US Centers for Disease Control and Prevention (CDC) launched the Global Adult Tobacco Survey (GATS) in 2007. GATS uses a standardized questionnaire to measure and track smoking, and key tobacco control indicators, in 25 low and middle income countries (LMIC), that account for over half of the world’s adult population and smokers2,4,14,15. Results from GATS are used to implement tobacco control, prevention measures, and to make comparisons with other countries2.
GATS China, a cross-sectional, nationally representative survey, was completed in 2010 and included: population demographics, tobacco usage, quitting behaviors, SHS exposures, economics; and knowledge, attitudes and perceptions about tobacco use2. GATS China included males and females age 15 years and older, excluding those living in dormitories, barracks, prisons, nursing homes, or hospitals2,4. Details of the interview, and the data compilation process, are available elsewhere2,4.
Study population
Stratified multi-stage cluster sampling was used, with probability-proportional-to-size random methods, for household selection. The first stage included urban districts or rural counties, the second stage identified neighborhood communities or villages, and the third stage selected groups of households at random2. One person was selected randomly from each household to participate in the survey2.
GATS China aimed at a sample size of 15 000 participants, representative of China’s six geographic regions2, each of which were further stratified into urban and rural areas4. Following exclusion criteria, 13 562 household interviews were completed, with an overall household response rate of 97.5%2. With an individual-level response rate of 98.5%, 13 354 nationally representative men and women age 15 years and older completed the interview in 2010, with 5832 and 7522 participants from urban and rural areas, respectively2. There were 4866 ever-smokers (current and former smokers) included for analyses of quitting smoking2. Analyses of attempts and intention to quit smoking included 4010 current smokers.
Variables
The outcome variables for this study included ‘ever intended to quit smoking’ (yes, no), ‘attempted to stop smoking’ (yes, no), and ‘quit smoking’ (current smoker, former smoker). ‘Intended to quit’ included ‘within the next month’, ‘within the next year’, and ‘someday but not within the next year’. ‘Current’ smokers were those who smoked any tobacco product on a daily or less than daily basis. ‘Former’ smokers were those who, in the past, had smoked any tobacco product daily.
The key exposure variable was ‘belief that breathing smoke from other people’s cigarettes causes serious illness in non-smokers (yes, no)’.
Covariates included ‘believed smoking causes serious illness, stroke, heart disease, or cancer’ (yes, no). ‘No’ also included ‘do not know’. Other covariates were ‘had seen or heard information about the dangers of smoking in newspapers, magazines, television, billboards, posters, promotional materials, public transportation vehicles, stations, or somewhere else’ (yes, no). ‘Somewhere else’ included radio, public walls, cinemas, internet, or elsewhere. Another covariate was ‘had noticed any advertisements or signs promoting cigarettes anywhere’ (yes, no). ‘Anywhere’ included point of sale, television, radio, billboards, posters, promotional materials, newspapers, magazines, cinemas, internet, public transportation vehicles, stations, public walls, or elsewhere. Other variables were ‘visited a doctor or another healthcare provider in the last 12 months’ (yes, no) and ‘the rule about smoking at home’ (allowed, not allowed). ‘Allowed’ also included ‘no rules’, and ‘don’t know’. ‘Not allowed’ included ‘never allowed’, and ‘not allowed, but exceptions’.
Additional covariates were gender, age group (15-24, 25-44, 45-64, 65+), highest level of education completed (no formal schooling, completed primary, completed secondary, university or higher), employment status over the previous 12 months (agriculture/forestry/fishery employee, transportation/equipment operator, business/service industry employee, other occupation, unemployed), residence (urban, rural), region (North, North-East, East, Mid-South, South-West, North-West).
Analysis
Descriptive frequencies are reported for current smokers and ever-smokers. Odds ratio (OR) was used to evaluate the magnitude of the associations between exposures of interest (beliefs that smoking or SHS causes illness, stroke, lung cancer, or heart attack; noticed smoking warnings in newspapers, television, billboards, posters, public transportation, or elsewhere; noticed signs promoting cigarettes; the rule about smoking at home; doctor visits; gender; age; education; employment; residence; and region) and outcomes (intention to quit, attempts to quit, and quitting smoking).
Statistical significance was evaluated through the Wald chi-square test. Variables found to be significant at p<0.10 from bivariate analyses were included in step-wise multivariable logistic regression models to evaluate associations with the outcomes of interest (intention to quit, attempts to quit, and quitting smoking). Variables associated with outcomes at p<0.05, as well as the main exposure, the belief that SHS causes serious illness, were retained in the final models. The order of variables included in models was determined by significance. After significant variables were entered into the models from bivariate analyses, interaction terms cited in the literature were assessed, including the belief that SHS causes serious illness by gender, education, and home smoking rules2,16,17. Pairwise correlation coefficients, tolerance values, and the condition number (CN) were examined to assess interrelationships among covariates similar in construct for collinearity18. Adjusted ORs and 95% Confidence Intervals (CIs) are reported. All analyses were calculated using SAS V.9.4 (SAS Institute, Inc., Cary, North Carolina). The surveyfreq and surveylogistic procedures were used to account for cluster, strata, and weight factors.
RESULTS
Of the nationally representative sample of 13 354 men and women in China in 2010, current smokers were 4010 and former smokers were 856. After accounting for cluster, strata, and weight factors, this represents 28.1% as current smokers and 5.4% as former smokers (Table 1). Correlation matrices revealed no highly correlated interrelationships among any of the covariates examined, the tolerance values were well above 0.10, and the CN=3.36 was far below the rule-of-thumb of 30 (not tabulated)18. Therefore, there was no evidence of collinearity.
Table 1.
Descriptive statisticsa of current and former smokers, 2010 China Global Adult Tobacco Survey
| Characteristic | Current smokers Proportion % (Std Err %) | Former smokers Proportion % (Std Err %) |
|---|---|---|
| Believe SHS causes illness | ||
| Yes | 59.4 (2.3) | 67.0 (2.7) |
| No | 40.6 (2.3) | 33.0 (2.7) |
| Believe smoking causes Serious illness | ||
| Yes | 79.7 (1.6) | 86.7 (2.0) |
| No | 20.3 (1.6) | 13.3 (2.0) |
| Lung cancer | ||
| Yes | 81.8 (1.6) | 82.0 (2.2) |
| No | 18.2 (1.6) | 18.0 (2.2) |
| Stroke | ||
| Yes | 32.2 (1.9) | 36.4 (2.7) |
| No | 67.8 (1.9) | 63.6 (2.7) |
| Heart attacks | ||
| Yes | 42.5 (1.8) | 48.7 (3.0) |
| No | 57.5 (1.8) | 51.3 (3.0) |
| Rule about smoking at home | ||
| Not allowed | 12.7 (1.4) | 27.2 (3.5) |
| Allowed | 87.3 (1.4) | 72.8 (3.5) |
| Noticed smoking warnings (ref: no) In newspapers | ||
| Yes | 22.1 (2.0) | 23.4 (2.6) |
| No | 77.9 (2.0) | 76.6 (2.6) |
| On billboards | ||
| Yes | 20.6 (2.2) | 19.8 (2.3) |
| No | 79.4 (2.2) | 80.2 (2.3) |
| On television | ||
| Yes | 46.8 (2.9) | 47.9 (2.9) |
| No | 53.2 (2.9) | 52.1 (2.9) |
| On posters | ||
| Yes | 9.7 (1.5) | 8.8 (1.5) |
| No | 90.3 (1.5) | 91.2 (1.5) |
| On vehicles | ||
| Yes | 21.0 (2.4) | 17.9 (2.3) |
| No | 79.0 (2.4) | 82.1 (2.3) |
| Elsewhere | ||
| Yes | 15.6 (1.7) | 15.0 (2.5) |
| No | 84.4 (1.7) | 85.0 (2.5) |
| Noticed cigarette promotions | ||
| Yes | 19.1 (2.0) | 12.8 (1.8) |
| No | 80.9 (2.0) | 87.2 (1.8) |
| Visited a doctor in past yearb | ||
| Yes | 29.2 (1.8) | - |
| No | 70.8 (1.8) | - |
| Gender | ||
| Male | 95.8 (0.5) | 93.4 (1.0) |
| Female | 4.2 (0.5) | 6.6 (1.0) |
| Age | ||
| 15-24 | 10.9 (1.4) | 5.8 (1.9) |
| 25-44 | 42.4 (1.7) | 24.3 (2.3) |
| 45-64 | 37.6 (1.3) | 41.7 (3.0) |
| 65+ | 9.1 (0.6) | 28.2 (2.6) |
| Education | ||
| <Primary | 11.8 (1.1) | 17.8 (2.0) |
| <Secondary | 18.6 (1.6) | 23.7 (2.2) |
| Secondary | 59.8 (2.0) | 49.4 (2.7) |
| College | 9.8 (1.2) | 9.1 (1.6) |
| Employment | ||
| Unemployed | 12.0 (1.3) | 32.5 (3.4) |
| AFF | 34.5 (4.0) | 31.0 (4.2) |
| Transportation | 19.6 (1.9) | 8.9 (1.7) |
| Business/service | 16.5 (1.6) | 10.2 (1.5) |
| Other | 17.4 (1.7) | 17.4 (3.1) |
| Residence | ||
| Rural | 57.2 (5.5) | 54.6 (5.5) |
| Urban | 42.8 (5.5) | 45.4 (5.5) |
| Region | ||
| North | 13.1 (2.0) | 8.4 (1.5) |
| North-East | 10.7 (0.9) | 19.0 (2.9) |
| East | 28.0 (3.0) | 32.2 (4.1) |
| Mid-South | 17.8 (1.7) | 17.1 (2.1) |
| South-West | 23.7 (2.3) | 17.7 (4.2) |
| North-West | 6.7 (1.6) | 5.6 (1.8) |
SHS: secondhand smoke; AFF: agriculture, forestry, fishing
Sample weights were used to account for clustering and stratification factors
Collected for current smokers only
Intended to quit
Variables associated with intention to quit from bivariate analyses at p<0.10 included the belief that: SHS causes serious illness (p<0.001); the belief that smoking causes serious illness (p<0.001) or lung cancer (p=0.001); home smoking rules (p=0.005); noticed information about the dangers of smoking on billboards (p=0.022), on television (p=0.020), or on public vehicles (p<0.001); noticed signs promoting cigarettes (p=0.018); age (p<0.001); and education (p=0.001) (Table 2).
Table 2.
Intended to quit smoking: unadjusted and adjusted associationsa with the belief that secondhand smoke causes serious illness among current smokers, 2010 China Global Adult Tobacco Survey
| Characteristic | Intended to quit prevalence % (Std Err %) | Unadjusted OR ( 95% CI) | p-value | Adjustedb OR ( 95% CI) | p-value |
|---|---|---|---|---|---|
| Believe SHS causes illness (ref: no) | 46.8 (2.9) | 1.79 (1.40, 2.29) | <0.001 | 1.62 (1.24, 2.12) | <0.001 |
| Believe smoking causes (ref: no) | |||||
| Serious illness | 45.6 (2.6) | 2.67 (2.07, 3.45) | <0.001 | - | - |
| Lung cancer | 43.3 (2.6) | 1.65 (1.23, 2.20) | 0.001 | 1.36 (1.00, 1.83) | 0.044 |
| Stroke | 41.6 (3.6) | 1.02 (0.75, 1.41) | 0.882 | - | - |
| Heart attacks | 43.2 (3.2) | 1.15 (0.89, 1.49) | 0.283 | - | - |
| Smoking not allowed at home (ref: allowed) | 53.2 (4.2) | 1.74 (1.18, 2.57) | 0.005 | 1.59 (1.10, 2.31) | 0.013 |
| Noticed smoking warnings (ref: no) | |||||
| In newspapers | 45.5 (3.7) | 1.25 (0.92, 1.70) | 0.149 | - | - |
| On billboards | 48.1 (4.2) | 1.43 (1.05, 1.94) | 0.022 | - | - |
| On television | 44.6 (2.6) | 1.30 (1.04, 1.62) | 0.020 | - | - |
| On posters | 45.4 (5.9) | 1.21 (0.78, 1.87) | 0.388 | - | - |
| On vehicles | 49.6 (3.1) | 1.54 (1.23, 1.93) | <0.001 | - | - |
| Elsewhere | 48.2 (6.5) | 1.40 (0.89, 2.21) | 0.140 | - | - |
| Noticed cigarette promotions (ref: no) | 48.2 (4.5) | 1.42 (1.06, 1.91) | 0.018 | - | - |
| Visited a doctor in past year (ref: no) | 43.6 (2.1) | 1.15 (0.92, 1.44) | 0.225 | - | - |
| Male (ref: female) | 41.5 (2.3) | 1.39 (0.90, 2.17) | 0.136 | - | - |
| Age (ref: 15-24) | <0.001 | - | |||
| 25-44 | 44.4 (3.2) | 1.32 (0.75, 2.30) | - | ||
| 45-64 | 41.3 (2.6) | 1.16 (0.72, 1.88) | - | ||
| 65+ | 30.2 (2.9) | 0.71 (0.41, 1.25) | - | ||
| Education (ref: <primary) | 0.001 | - | |||
| <Secondary | 38.3 (2.4) | 1.32 (0.97, 1.80) | - | ||
| Secondary | 44.5 (3.0) | 1.71 (1.31, 2.24) | - | ||
| College | 37.8 (3.8) | 1.29 (0.89, 1.88) | - | ||
| Employment (ref: unemployed) | 0.144 | - | |||
| AFF | 43.0 (4.7) | 1.10 (0.76, 1.60) | - | ||
| Transportation | 38.4 (2.2) | 0.91 (0.66, 1.26) | - | ||
| Business/service | 49.1 (4.7) | 1.41 (1.00, 1.98) | - | ||
| Other | 37.0 (3.4) | 0.86 (0.61, 1.21) | - | ||
| Rural residence (ref: urban) | 41.1 (2.5) | 0.99 (0.68, 1.42) | 0.941 | - | - |
| Region (ref: South-West) | 0.954 | - | |||
| North | 43.2 (4.7) | 0.84 (0.45, 1.57) | - | ||
| North-East | 39.0 (4.3) | 0.90 (0.53, 1.53) | - | ||
| East | 38.9 (5.6) | 1.00 (0.57, 1.76) | - | ||
| Mid-South | 40.7 (3.9) | 0.84 (0.48, 1.46) | - | ||
| North-West | 44.5 (5.8) | 1.06 (0.56, 1.97) | - | ||
CI: confidence interval; OR: odds ratio; SHS: secondhand smoke; AFF: agriculture, forestry, fishing
Sample weights were used to account for clustering and stratification factors
Adjusted for all of the other variables listed in the model
The final model for current smokers intending to quit smoking included the belief that SHS causes serious illness (AOR: 1.62; 95% CI: 1.24, 2.12, Table 2), the belief that smoking causes lung cancer (AOR: 1.36, 95% CI: 1.00, 1.83), and rules not allowing smoking at home (AOR: 1.59, 95% CI: 1.10, 2.31). Interaction terms were not significant at p<0.05.
Attempted to quit
Variables associated with attempts to quit from bivariate analyses at p<0.10 included the belief that smoking causes serious illness (p=0.004) and heart attacks (p=0.092), home smoking rules (p<0.001), noticed information about the dangers of smoking in newspapers (p=0.016) or on billboards (p=0.001), visited a doctor (p=0.010), and age (p=0.065) (Table 3).
Table 3.
Attempted to quit smoking: unadjusted and adjusted associationsa with the belief that secondhand smoke causes serious illness among current smokers, 2010 China Global Adult Tobacco Survey
| Characteristic | Attempted to quit prevalence % (Std Err %) | Unadjusted OR ( 95% CI) | p-value | Adjustedb OR ( 95% CI) | p-value |
|---|---|---|---|---|---|
| Believe SHS causes illness (ref: no) | 38.0 (2.7) | 1.05 (0.79, 1.40) | 0.745 | 0.84 (0.60, 1.16) | 0.282 |
| Believe smoking causes (ref: no) | |||||
| Serious illness | 39.6 (2.3) | 1.58 (1.15, 2.16) | 0.004 | 1.63 (1.14, 2.33) | 0.007 |
| Lung cancer | 38.0 (2.2) | 1.13 (0.85, 1.52) | 0.398 | - | - |
| Stroke | 38.8 (2.6) | 1.09 (0.84, 1.40) | 0.522 | - | - |
| Heart attacks | 40.0 (2.7) | 1.20 (0.97, 1.49) | 0.092 | - | - |
| Smoking not allowed at home (ref: allowed) | 50.2 (3.5) | 1.82 (1.32, 2.50) | <0.001 | 1.73 (1.25, 2.40) | 0.001 |
| Noticed smoking warnings (ref: no) | |||||
| In newspapers | 42.8 (2.5) | 1.33 (1.05, 1.68) | 0.016 | - | - |
| On billboards | 44.6 (2.8) | 1.45 (1.15, 1.83) | 0.001 | 1.34 (1.03, 1.75) | 0.026 |
| On television | 39.7 (1.9) | 1.19 (0.90, 1.57) | 0.225 | - | - |
| On posters | 40.8 (4.1) | 1.16 (0.82, 1.64) | 0.387 | - | - |
| On vehicles | 37.0 (3.4) | 0.97 (0.72, 1.31) | 0.860 | - | - |
| Elsewhere | 38.9 (4.0) | 1.07 (0.77, 1.50) | 0.675 | - | - |
| Noticed cigarette promotions (ref: no) | 35.7 (3.2) | 0.91 (0.68, 1.22) | 0.515 | - | - |
| Visited a doctor in past year (ref: no) | 43.6 (2.6) | 1.43 (1.09, 1.88) | 0.010 | 1.46 (1.12, 1.90) | 0.005 |
| Male (ref: female) | 37.6 (2.0) | 1.06 (0.71, 1.59) | 0.759 | - | - |
| Age (ref: 15-24) | 0.065 | - | |||
| 25-44 | 35.8 (2.4) | 1.48 (0.88, 2.49) | - | ||
| 45-64 | 42.2 (2.5) | 1.94 (1.08, 3.49) | - | ||
| 65+ | 38.4 (3.0) | 1.65 (0.84, 3.24) | - | ||
| Education (ref: <primary) | 0.128 | - | |||
| <Secondary | 40.2 (2.8) | 1.30 (1.04, 1.63) | - | ||
| Secondary | 37.6 (2.5) | 1.17 (0.89, 1.53) | - | ||
| College | 36.2 (3.4) | 1.10 (0.79, 1.53) | - | ||
| Employment (ref: unemployed) | 0.616 | - | |||
| AFF | 37.6 (3.6) | 0.80 (0.54, 1.19) | - | ||
| Transportation | 35.2 (4.0) | 0.73 (0.48, 1.11) | - | ||
| Business/service | 37.1 (3.1) | 0.79 (0.51, 1.21) | - | ||
| Other | 36.7 (2.8) | 0.77 (0.52, 1.16) | - | ||
| Rural residence (ref: urban) | 38.6 (2.7) | 1.12 (0.83, 1.50) | 0.463 | - | - |
| Region (ref: South-West) | 0.188 | - | |||
| North | 37.6 (2.5) | 1.31 (0.81, 2.12) | - | ||
| North-East | 44.5 (4.4) | 1.75 (1.00, 3.06) | - | ||
| East | 34.5 (3.8) | 1.15 (0.66, 1.98) | - | ||
| Mid-South | 44.6 (4.3) | 1.75 (1.01, 3.04) | - | ||
| North-West | 41.3 (5.5) | 1.53 (0.82, 2.85) | - | ||
CI: confidence interval; OR: odds ratio; SHS: secondhand smoke; AFF: agriculture, forestry, fishing
Sample weights were used to account for clustering and stratification factors
Adjusted for all of the other variables listed in the model
The final model for current smokers attempting to quit smoking included the belief that SHS causes serious illness (AOR 0.84, 95% CI: 0.60, 1.16, Table 3), the belief that smoking causes serious illness (AOR: 1.63, 95% CI: 1.14, 2.33), rules not allowing smoking at home (AOR: 1.73, 95% CI: 1.25, 2.40), noticed smoking warnings on billboards (AOR: 1.43, 95% CI: 1.03, 1.75), and visited a doctor within the past year (AOR: 1.46, 95% CI: 1.12, 1.90). Interaction terms were not significant at p<0.05.
Quit smoking
Variables associated with quitting smoking from bivariate analyses at p<0.10 included the belief that SHS causes serious illness (p=0.004), the belief that smoking causes serious illness (p=0.001) or heart attacks (p=0.006), home smoking rules (p<0.001), noticed signs promoting cigarettes (p=0.004), gender (p=0.005), age (p<0.001), education (p=0.001), employment (p<0.001), and region (p<0.001) (Table 4).
Table 4.
Quit smoking: unadjusted and adjusted associationsa with the belief that secondhand smoke causes serious illness among ever-smokersb, 2010 China Global Adult Tobacco Survey
| Characteristic | Prevalence % among former smokers (Std Err %) | Unadjusted OR ( 95% CI) | p-value | Adjustedb OR ( 95% CI) | p-value |
|---|---|---|---|---|---|
| Believe SHS causes illness (ref: no) | 17.7 (1.5) | 1.38 (1.10, 1.73) | 0.004 | 1.44 (1.15, 1.81) | 0.002 |
| Believe smoking causes (ref: no) | |||||
| Serious illness | 17.2 (1.3) | 1.66 (1.21, 2.27) | 0.001 | 1.66 (1.21, 2.28) | 0.002 |
| Lung cancer | 16.1 (1.2) | 1.01 (0.77, 1.32) | 0.946 | - | - |
| Stroke | 17.8 (1.9) | 1.21 (0.93, 1.56) | 0.148 | - | - |
| Heart attacks | 18.8 (1.7) | 1.43 (1.10, 1.85) | 0.006 | - | - |
| Smoking not allowed at home (ref: allowed) | 29.1 (3.5) | 2.57 (1.86, 3.56) | <0.001 | 2.71 (1.90, 3.89) | <0.001 |
| Noticed smoking warnings (ref: no) | |||||
| In newspapers | 16.8 (2.1) | 1.08 (0.78, 1.49) | 0.661 | - | - |
| On billboards | 15.5 (2.0) | 0.95 (0.69, 1.30) | 0.732 | - | - |
| On television | 16.4 (1.3) | 1.04 (0.78, 1.41) | 0.774 | - | - |
| On posters | 14.8 (2.3) | 0.90 (0.62, 1.33) | 0.599 | - | - |
| On vehicles | 14.0 (2.0) | 0.82 (0.59, 1.16) | 0.255 | - | - |
| Elsewhere | 15.5 (2.7) | 0.96 (0.65, 1.41) | 0.817 | - | - |
| Noticed cigarette promotions (ref: no) | 11.4 (1.7) | 0.62 (0.45, 0.86) | 0.004 | - | - |
| Male (ref: female) | 15.7 (1.1) | 0.62 (0.44, 0.87) | 0.005 | - | - |
| Age (ref: 15-24) | <0.001 | <0.001 | |||
| 25-44 | 9.9 (1.5) | 1.06 (0.54, 2.08) | 1.02 (0.54, 1.92) | ||
| 45-64 | 17.5 (1.2) | 2.06 (0.97, 4.38) | 1.92 (0.97, 3.80) | ||
| 65+ | 37.2 (2.5) | 5.76 (3.01, 11.03) | 4.72 (2.68, 8.32) | ||
| Education (ref: <primary) | 0.001 | - | |||
| <Secondary | 19.5 (1.9) | 0.84 (0.60, 1.19) | - | ||
| Secondary | 13.6 (1.4) | 0.55 (0.41, 0.74) | - | ||
| College | 15.1 (2.0) | 0.62 (0.41, 0.93) | - | ||
| Employment (ref: unemployed) | <0.001 | <0.001 | |||
| AFF | 14.7 (1.6) | 0.33 (0.24, 0.46) | 0.60 (0.44, 0.82) | ||
| Transportation | 8.0 (1.5) | 0.17 (0.10, 0.27) | 0.29 (0.17, 0.49) | ||
| Business/service | 10.5 (1.7) | 0.23 (0.16, 0.33) | 0.39 (0.27, 0.57) | ||
| Other | 16.0 (2.8) | 0.37 (0.24, 0.58) | 0.56 (0.36, 0.89) | ||
| Rural residence (ref: urban) | 15.4 (1.3) | 0.90 (0.67, 1.20) | 0.468 | - | - |
| Region (ref: South-West) | <0.001 | 0.001 | |||
| North | 10.9 (1.5) | 0.86 (0.47, 1.56) | 1.62 (0.87, 3.02) | ||
| North-East | 25.4 (3.1) | 2.39 (1.31, 4.36) | 1.52 (0.85, 2.72) | ||
| East | 18.0 (2.4) | 1.54 (0.84, 2.82) | 0.76 (0.38, 1.49) | ||
| Mid-South | 15.5 (2.0) | 1.29 (0.71, 2.33) | 2.23 (1.23, 4.05) | ||
| North-West | 13.8 (3.0) | 1.13 (0.55, 2.31) | 0.88 (0.39, 1.99) |
CI: confidence interval; OR: odds ratio; SHS: secondhand smoke; AFF: agriculture, forestry, fishing
Sample weights were used to account for clustering and stratification factors
Ever-smokers include current and former smokers
c Adjusted for all of the other variables listed in the model
The final model for ever-smokers quitting smoking included the belief that SHS causes serious illness (AOR: 1.44; 95% CI: 1.15, 1.81, Table 4), the belief that smoking causes serious illness (AOR: 1.66, 95% CI: 1.21, 2.28), and rules not allowing smoking at home (AOR: 2.71, 95% CI: 1.90, 3.89). The final model also included age (p<0.001), employment (p<0.001), and region (p=0.001) (Table 4). Interaction terms were not significant at p<0.05.
DISCUSSION
The results of this study demonstrate that current smokers’ attitudes about exposure to SHS could play an important role in the overall strategy to reduce tobacco use in China. The aim of this study was to ascertain whether the belief that SHS causes serious illness was associated with intention to quit, attempts to quit, and quitting smoking among Chinese adult smokers. After adjusting for covariates, there was a significant association between the belief that SHS causes serious illness and intention to quit and quitting smoking. But the association between the belief that SHS causes serious illness and attempting to quit smoking did not reach statistical significance. Analyses also indicated significant associations with several covariates: rules about smoking at home, noticed information on billboards about the dangers of smoking, noticed signs promoting cigarettes, visited a doctor within the past year, and the belief that smoking causes lung cancer. The belief that exposure to SHS causes serious illness is an additional element to include in a comprehensive tobacco-control strategy.
The finding that smokers who believe SHS exposure causes serious illness were more likely to intend to quit smoking or quit smoking is consistent with other studies6,19. Concern about exposing others, particularly children, to SHS has been cited as one of the strongest indicators for quitting smoking19,20. Increasing knowledge of the dangers of SHS also decreases tolerance for smoking at home6,19,20. This finding may in part be explained by Chinese culture, which values responsibility to one’s family and filial piety respect for one’s parents and ancestors11,13. China has a highly collectivistic culture in which the needs of the group come before the needs of the individual21. If smoking is perceived as a threat to the health of one’s family, collectivism may explain a willingness among Chinese smokers to quit smoking in order to protect members of their in-group21,22. Social disapproval of smoking is a more significant predictor of regretting smoking in China than in Western countries, which may induce quitting smoking behavior22,23. Strong family relationships are also associated with abstaining from smoking in China25. Future anti-tobacco campaigns should focus on education about the dangers of exposures to SHS in the context of one’s in-group and family25,26.
Although only 2.4% of women smoke in China, 72.4% are exposed to SHS, with 38.0% exposed on a daily basis, many of whom do not recognize the dangers of SHS exposure27. Consequently, women bear nearly 80% of the burden of disease due to SHS exposure28. Children in China with chronic exposure to SHS have respiratory problems that continue into adulthood, including impaired lung function, coughing, sneezing, and phlegm29. Smoke-free laws that are strictly enforced have resulted in a significant reduction in SHS exposure in the public places of Guangzhou, Harbin, Shanghai, Shenzhen, and Tiajin30. Greater efforts are required to promote smoke-free environments that weaken smoking customs30.
After adjusting for covariates, the belief that SHS causes serious illness did not reach statistical significance for attempting to quit smoking. Previous research has demonstrated that health concerns for friends and family are among the primary reasons Chinese adult smokers attempt to quit smoking11,12. However, quit attempts are less successful in China among smokers without firsthand experiences of the adverse health effects of smoking tobacco, personally or within the family11,12. Education must also include outreach to smokers living alone and who may not feel the onus of protecting family and friends.
The finding that adult smokers who did not allow smoking at home were 2.46 times more likely to quit smoking is in accord with published data31,32. Home-smoking bans have proven to be powerful smoking interventions: they reduce the likelihood of being a current smoker, reduce the number of cigarettes consumed per day, and increase the number of quit attempts31. In China, concern regarding the health effects of SHS exposure was the greatest reason for not allowing smoking at home, but most families still allow smoking in at least one room2,32. Current laws in China ban smoking in selected outdoor locations and all indoor public places, including gymnasiums, libraries, museums, trains, classrooms, dorms, and schools2. There is a paucity of information about penalties for violations of these regulations however, and there is no national ban on smoking in the workplace in China2.
The result that smokers who noticed information about the dangers of smoking on billboards were more likely to have attempted to quit also aligns with the literature, which demonstrates that mass media campaigns are effective tobacco-control methods33,34. Of the media analyzed that displayed smoking, only billboards reached statistical significance for attempted to quit. Visually explicit advertisements are particularly successful for increasing quit attempts34. Billboards displaying adverse health outcomes of smoking increase public awareness of smoking dangers and decrease smoking prevalence33. Billboards may also include Quitline service information, which has shown promise as a smoking cessation service in Hong Kong35.
The results further suggest that adult smokers who believe smoking causes serious illness were more likely to have intended or attempted to quit, which is in accord with other studies25,26. Most former smokers cite health concerns as the primary motivation for quitting smoking, but the perceived risks and harms of smoking are low in China compared to other countries25,26. Among Chinese smokers, the greatest factor for attempting and intending to quit is knowledge of the adverse health effects of smoking, but misconceptions regarding health consequences of smoking remain pervasive among Chinese smokers11,12. Educational campaigns to improve public perceptions of smoking risks, combined with social support and accessible smoking cessation clinics, are effective strategies to increase quit attempts11,12,36.
Noticing signs promoting cigarettes was not significantly associated in this study with quitting smoking behavior, and numerous studies have demonstrated that tobacco advertisements foster positive attitudes about tobacco use37,38. At the time GATS was conducted in 2010, China did not have laws or regulations for restricting the advertising or promoting of tobacco products2,38. Since GATS was conducted, a subsequent law banned the use of signs and mass media to advertise or promote cigarettes2. The challenge is to ensure that these new regulations are enforced2.
Smokers who attempted to quit smoking were more likely to have visited a doctor within the past year, which also agrees with the literature20,39. Simple advice or brief interventions from nonsmoking physicians have been shown to be a cost-effective means to increase quit attempts and quit rates20,39. Larger interventions and pharmacotherapy are even more successful for smokers with high nicotine dependence in China39,40. However, this message may be muted by virtue of the fact that 46.7% of male physicians in China have been reported as active smokers41.
Limitations
The findings of this study are subject to limitations. The use of cross-sectional survey data limits our ability to make causal inferences between the exposure variables and quitting smoking behavior. Furthermore, the overall prevalence of smoking has likely been under represented as roughly 200 million Chinese workers, who are known to have a disproportionately high number of smokers compared to the rest of the country, work and live in temporary accommodation away from their registered household2. Another limitation is that GATS data include only one smoker per household, which precludes the analysis of the influence of other smokers on smoking proclivity2. Other survey limitations include self-reporting and recall biases2.
CONCLUSIONS
The results of this study contribute an additional significant tenet to a comprehensive tobacco-control strategy, namely, the belief that exposure to SHS causes serious illness. This message can be incorporated into the other, established control methods like explicit warning labels, high taxes, physician advice, and mass media campaigns, to help decrease the overall burden of tobacco use.
ACKNOWLEDGEMENTS
The author appreciates the encouragement, assistance and advice from Dr. Thomas Novotny, MD, MPH, Deputy Assistant Secretary for Health (Science and Medicine), U.S. Department of Health & Human Services.
CONFICT OF INTEREST
Author has completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none was reported.
FUNDING
There was no source of funding for this research.
PROVENANCE AND PEER REVIEW
Not commissioned; externally peer reviewed
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