Abstract
Introduction:
Reasons for using and stopping the use of e-cigarettes and their associations with transitions in nicotine product use are relatively unknown in countries with e-cigarette bans, as in Mexico.
Methods:
Data comes from an open cohort of people who smoke in Mexico, surveyed every 4 months from November 2018 to November 2021. Those who smoked and used e-cigarettes at time t (n=904 individuals, 1653 observations) were categorized at 4-month follow-up (t+1): a) continued “dual use,” b) exclusive smoking, c) exclusive use of e-cigarettes or neither product. For people who formerly used e-cigarettes at time t (n=332 individuals, 372 observations), follow-up categories were: a) continued exclusive smoking; b) re-initiated e-cigarette use. Multinomial and logistic models regressed follow-up status (ref=status at time t) on reasons for using or stopping e-cigarette use, respectively, at time t, adjusting for covariates.
Results:
The most prevalent reasons for current e-cigarette use were “they were less harmful to others” (40.5%) and “enjoyable” (39.0%). Those who reported using e-cigarettes because they were less harmful to others (ARRR=0.68), more enjoyable (ARRR=0.52), could help them to quit smoking (ARRR=0.65), or to control weight (ARRR=0.46) were less likely to return to exclusively smoking. Among people who formerly used e-cigarettes, lack of satisfaction was the primary reason for stopping e-cigarette use (32%), and those who reported this were less likely to start using e-cigarettes again at follow-up (AOR=0.58).
Conclusions:
Specific reasons for using and stopping e-cigarettes predict changes in smoking and e-cigarette use, and targeting these beliefs could promote desired behavior changes.
Introduction
E-cigarettes are electronic devices that aerosolize a solution (e-liquid) that delivers nicotine, additives, propylene glycol, glycerin and flavorings to the mouth and lungs of the user.1 Though they are not harmless, e-cigarettes deliver lower levels of carcinogens than combustible cigarettes,2 potentially serving as a less harmful substitute for combustible cigarettes. As e-cigarette use has grown exponentially over the past decade,3–7 uncertainties around their ability to help people who smoke to quit smoking, coupled with rising use among youth,8 have made their regulation one of the main challenges in tobacco control.9
Most studies assessing reasons to use e-cigarettes have been conducted amongst adults who smoke or formerly smoked and live in the US, where e-cigarettes are legal. In the US, the most common reasons for using e-cigarettes were perceived lower harm to others and oneself than smoking,10,11 for smoking cessation,12 to cut down on smoking,13 and enjoyment.13 The most prevalent reasons for discontinuing e-cigarette use were dissatisfaction with its use, being unhelpful reducing smoking cravings or quitting smoking,10 and concerns about their harms.13 One study compared reasons for use among people who smoke and use e-cigarettes across countries with contrasting regulatory contexts.10 In Australia, where e-cigarettes are banned but with poor enforcement, the relatively high e-cigarette affordability was the only reason that differed with the US and Canada, Also, citing helpfulness with quitting and enjoyment was higher in Australia than in England. This study also evaluated reasons for stopping e-cigarette use among people who smoke, finding that more of those in England than Australia cited a lack of satisfaction for why the stopped use.10 Finally, those from the US and England were less likely than those in Australia to report that feeling uncomfortable while using e-cigarettes in public was a reason for stopping use. Overall, this study suggests that reasons for use and stopping use are generally similar across regulatory environments, although this latter finding regarding discomfort with using e-cigarettes in public aligns with expectations around whether e-cigarettes are legal or banned.
To our knowledge, only one longitudinal study in the US examined how the motivations for using e-cigarettes were associated with product transitions among people who smoke and use e-cigarettes.11 Most continued using both products over time (88.4%), and 11.6% stopped smoking. Of 13 reasons queried for using e-cigarettes, only those who did not indicate they used e-cigarettes because they could do so where smoking is not allowed were more likely to stop smoking. Among those who smoked and formerly used e-cigarettes, 27.2% re-initiated e-cigarette use, although associations with reasons for use or stopping use were not assessed. 11
Mexico has banned e-cigarette sales since 2008 14 and their importation since 2020.15 In Mexico, current e-cigarette use is substantially higher among adults who currently smoke combustible cigarettes (9.7%) than those who do not (1.1%).16 A longitudinal study found that people who smoke and use e-cigarettes were just as likely as those who exclusively smoked to either quit or change their smoking frequency.17 More recent data (2018–2020) suggest that Mexican adults who smoke and use e-cigarettes use are no more likely to quit smoking than those who exclusively smoke.17, 18 It is unclear whether the reasons for using or stopping use of e-cigarettes may be different in Mexico or other contexts outside high-income countries or where e-cigarettes are illegal.
The purpose of this study was to explore the prevalence of different self-reported reasons for using and stopping the use of e-cigarettes among Mexicans adults who smoke and either currently or formerly used e-cigarettes. We also evaluated whether these reasons were associated with changes in smoking and/or e-cigarettes use at four-month follow-up, to identify potential target beliefs for future interventions.
Methods
Sample
An open cohort of Mexican adults who smoke and/or use e-cigarettes was recruited from an online commercial research panel through a non-probability sample, with 8 surveys conducted every four months from November 2018 to March 2021. The study included male and female adults (≥ 18 years) who reported smoking or using e-cigarettes within the last 30 days. Approximately 1500 people participated in each survey, with quotas used for education (i.e., at least 500 with high school or lower attainment) to help offset under-representation of lower SES populations in online samples in Mexico, and for e-cigarette use in the prior month (i.e., at least 500 participants who used e-cigarettes) to have enough sample size to evaluate transitions in product use within these groups. During data collection, those lost to follow-up were replenished with new participants to maintain the sample size of 1,500 at each survey. The retention rate among surveys was from wave 1 to 2 (30.1%), wave 2 to 3 (44.5%), wave 3 to 4 (36.1%), wave 4 to 5 (53%), wave 5 to 6 (46.7%), wave 6 to 7 (48.5%) and wave 7 to 8 (42.1%). Surveys were administered in Spanish using questions from the International Tobacco Control (ITC) survey.19 Participants provided consent prior to completing the survey, and all study procedures were approved by the Institutional Review Board and Ethics Committee of the National Institute of Public Health of Mexico (CI 1572).
We analyzed data from all of those who had at least two consecutive surveys, followed from one survey wave (time “t”) to the next wave (time “t + 1”). As we used time “t” data to predict time “t+1” outcomes, the number of observations any individual could contribute was 1 less than the number of consecutive surveys in which they participated. The analytic sample to explore reasons to use e-cigarettes included 1,653 observations from 904 individuals who reported using cigarettes and e-cigarettes in the prior 30 days. While the sample to explore the reasons to stop using e-cigarettes comprised 372 observations from 332 people who, at time “t” currently smoked and had previously used e-cigarettes, but not in the last 30 days. Participants who were exclusive e-cigarettes users at time “t” were excluded from the analysis due the irrelevance of some questions and to small sample size (n=100).
Measurements
Primary outcome: changes in smoking and e-cigarette use status at time “t + 1”.
Information of cigarette and e-cigarette use was collected in every wave. Transition outcomes for participants who used both products (dual use) at time “t” were calculated as follows: (a) participants who used (time “t”) and continued using e-cigarettes and smoking cigarettes at time “t + 1”, were categorized as “continued dual use”; (b) changed to exclusive smoking at time “t + 1“; (c) changed to exclusive e-cigarette use or no use of either e-cigarettes or cigarettes at time “t + 1”. The latter group combined these two types of changes due to low sample sizes.
The second transition outcomes for those who had formerly used e-cigarettes but currently only smoked at time “t” were set as follows: (a) continued exclusive smoking at time “t + 1”; (b) change to currently using e-cigarette (any use in the prior 30 days) at time “t + 1”. In this latter sample, participants who quit smoking during follow-up (n=9) were excluded from analyses due to their small sample size.
Reasons for e-cigarette use at time t.
Participants who reported using e-cigarettes in last 4 months, were asked to select all the reasons for using e-cigarettes, options included: 10 a) e-cigarettes are less harmful than smoking for the people around me; b) e-cigarettes are more acceptable than smoking to the people around me; c) I enjoy using e-cigarettes; d) I can use e-cigarettes in places where I cańt smoke; e) eventually, e-cigarettes will help me quit smoking; f) I save money by using e-cigarettes instead of smoking; g) e-cigarettes will help me to stay quit from smoking; h) e-cigarettes help me control my appetite or weight; and i) e-cigarettes help me decrease the number of cigarettes I smoke.
Reasons for stopping e-cigarette use among people who formerly used e-cigarettes at time t.
Participants who had previously used e-cigarettes, but not during the prior 4 months, were asked to select from a list all reasons they had for having stopped e-cigarette use: 10 a) I felt like I was getting addicted to e-cigarettes; b) e-cigarettes are very expensive; c) e-liquids are very expensive; d) I had negative experiences using them; e) I feel uncomfortable using e-cigarettes in public; f) I am concerned about how safe they are to use (overheating, e-liquid leakage, etc.); g) I do not find them satisfactory enough; h) I found out that using e-cigarettes requires too much effort; i) I decided they weren’t going to help me quit smoking; j) it didn’t stop the urge for smoking; k) I no longer need them to continue without smoking; and l) I was worried that e-cigarettes would harm my health.
Smoking- and e-cigarette related variables at time t.
Frequency of smoking and e-cigarette use was queried and recoded as: a) occasional dual use (i.e., those who smoke and use e-cigarettes < 3 times a week) (1–2 days per week), and b) frequent dual use (i.e., those who smoke and use e-cigarettes ≥3 times a week to daily). Participants also reported how often they smoked, from which we derived three categories of smoking frequency, considering the median frequency of smoking among Mexican adults: 20 non-daily, daily light (≤ 5 cigarettes per day), and daily heavy (>5 cigarettes per day). Participants were also asked about any attempts to quit smoking in the prior 4 months (No [reference] vs. yes), and intentions to quit smoking (recoded: No plan/plan to quit after 6 months [reference] vs. plan to quit smoking next month/1–6 months).
Covariates at time “t”
Participants reported their age (i.e., 18–29 [re; 30–39; 40–49; 50+ years old), gender (female [reference]; male), educational attainment; high school or less, technical studies or some college; university or more [reference], and monthly household income in Mexican pesos ($20.00 pesos was approximately equal to $1.00 U.S. dollar), which was recoded to: a) less than 8,000 MX monthly [reference]; b) 8,001 to 15,000 MX monthly; c) 15,001 to 20,000 MX monthly; d) >20,000 MX monthly; and e) I don’t know. Finally, a “time in sample” variable was derived to reflect the number of at least two consecutive surveys each participant answered, having as time frame from “t” to time “t + 1”, to adjust for the conditioning effects from prior survey participation.
Statistical analysis
We first estimated the prevalence of each reason for using and stopping use of e-cigarettes at time “t” for people who exclusively smoked and who also used e-cigarettes, respectively. These estimates integrated post-stratification weights, as the non-probability sample was not representative of the Mexican population. Cross-sectional weights were developed considering gender, age, and educational attainment among adults who exclusively smoked or smoked and used e-cigarettes based on the 2018 National Survey on Nutrition and Health (ENSANUT) in Mexico,21 with weights rescaled to the sample size. 22
Among those who used both products at time t, unadjusted and adjusted random-effects multinomial logit model regressed at time “t + 1” product use status (reference group=user) on the reasons for using e-cigarettes as reported at time “t”, among participants who contributed more than one observation. In the adjusted model, all reasons for using e-cigarettes were assessed in the same model while adjusting for time t covariates, including smoking- and e-cigarette-related other covariates as gender, age, educational attainment, household income, smoking frequency, quit attempts, quit intentions, and the number of surveys to which participants had responded. For people who currently smoked and had formerly used e-cigarettes at time “t”, unadjusted and adjusted logistic models under a Generalized Estimating Equations (GEE) approach with robust standard errors, regressed time “t + 1” product use status (reference=remained exclusively smoking) on reasons for stopping e-cigarettes, model considered repeated measures from participants who contributed more than one observation. All reasons to have stopped the use of e-cigarettes were included in the adjusted model, along with time t smoking- and e-cigarette-related variables, as well as sociodemographic covariates and “time in sample”. All analyses were conducted using Stata v.16 (Stata Corp, TX, USA).
Results
Characteristics of the analytic samples are in Table 1. Among those who used both cigarettes and e-cigarettes at time “t”, the most prevalent reasons for e-cigarette use (Figure 1) were: “less harmful than smoking for the people around me” (40.5%), “enjoyment” (39.0%), and “more acceptable than smoking to the people around me” (37.7%). The least prevalent reasons were: “to help me control my appetite or weight” (8.5%) and “I save money by using e-cigarettes instead of smoking” (17%).
Table 1.
Sample characteristics of adults who smoke and either use e-cigarettes (dual use) and who formerly used e-cigarettes at time “t”, Mexico 2018–2021
| Variables | Dual use (n=1,653) | Former e-cigarette use (n=372) | |||||
|---|---|---|---|---|---|---|---|
|
|
|
||||||
| n | % | Weighted* % |
n | % | Weighted* % |
||
|
|
|
||||||
| Age group | |||||||
| 18–29 | 563 | 34.1 | 53.8 | 95 | 25.5 | 36.4 | |
| 30–39 | 607 | 36.7 | 30.3 | 111 | 29.8 | 38.3 | |
| 40–49 | 337 | 20.4 | 10.8 | 90 | 24.2 | 13.1 | |
| 50 + | 146 | 8.8 | 5.2 | 76 | 20.4 | 12.3 | |
| Gender | |||||||
| Female | 758 | 45.9 | 20.5 | 197 | 53.0 | 28.0 | |
| Male | 895 | 54.1 | 79.5 | 175 | 47.0 | 72.1 | |
| Educational attainment | |||||||
| High school and less | 427 | 25.8 | 26.2 | 137 | 36.8 | 74.0 | |
| Technical/some college | 335 | 20.3 | 19.8 | 99 | 26.6 | 12.1 | |
| University and more | 891 | 53.9 | 54.0 | 136 | 36.6 | 13.8 | |
| Monthly household income (pesos ** ) | |||||||
| <$8,000 | 209 | 12.6 | 13.8 | 68 | 18.3 | 30.9 | |
| $8,001 - $15,000 | 466 | 28.2 | 30.7 | 122 | 32.8 | 36.2 | |
| $15,001 - $20,000 | 354 | 21.4 | 22.5 | 60 | 16.1 | 16.6 | |
| >$20,000 | 596 | 36.1 | 31.2 | 105 | 28.2 | 12.2 | |
| Donť know | 28 | 1.7 | 1.9 | 17 | 4.6 | 4.1 | |
| Smoking frequency | |||||||
| Non-daily | 789 | 48.2 | 50.2 | 179 | 48.9 | 52.3 | |
| Daily <= 5 cigs | 407 | 24.9 | 24.7 | 81 | 22.1 | 17.6 | |
| Daily > 5 cigs | 441 | 26.9 | 25.1 | 106 | 29.0 | 30.1 | |
| Smoking quit attempt in the last 4 months | |||||||
| No | 841 | 51.4 | 52.3 | 228 | 62.3 | 51.6 | |
| Yes | 796 | 48.6 | 47.7 | 138 | 37.7 | 48.4 | |
| Intention to quit smoking in next 6 months | |||||||
| No | 983 | 60.1 | 59.2 | 234 | 63.9 | 62.2 | |
| Yes | 654 | 40.0 | 40.8 | 132 | 36.1 | 37.8 | |
| E-cigarette frequency | |||||||
| Occasional e-cigarette use (<3 days/week) | 996 | 60.3 | 59.6 | N/A | N/A | ||
| Frequent e-cigarette use (3+days/week) | 657 | 39.8 | 40.5 | N/A | N/A | ||
| Time in sample *** | |||||||
| 2 waves | 726 | 43.9 | 46.2 | 170 | 45.7 | 56.6 | |
| 3 waves | 432 | 26.1 | 23.2 | 92 | 24.7 | 13.7 | |
| 4 waves | 209 | 12.6 | 17.4 | 61 | 16.4 | 16.7 | |
| 5 waves | 146 | 8.8 | 6.6 | 32 | 8.6 | 11.8 | |
| 6 waves | 83 | 5.0 | 4.6 | 9 | 2.4 | 0.52 | |
| 7 waves | 42 | 2.5 | 1.5 | 5 | 1.3 | 0.51 | |
| 8 waves | 15 | 0.9 | 0.5 | 3 | 0.8 | 0.12 | |
Weighted to 2018 national estimates of Mexican adults who exclusively smoke and who smoke and use e-cigarettes by age, education, and gender.
20 Mexican pesos=1 US dollar at time of data collection.
Time in sample: the number of consecutive surveys each participant completed, which reflects potential conditioning effects from prior survey participation and provides information on the number of observations each individual contributed to the analysis (i.e., 2 waves=1 observation; k waves=k-1 observations).
Figure 1. Prevalence of reasons to use or stop using e-cigarettes. Mexico 2018–2020. Weighted data for dual users and all participants. *.
* Weighted to 2018 national estimates of Mexican adults who exclusively smoke and who smoke and use e-cigarettes by age, education, and gender
Of those who used both cigarettes and e-cigarettes at time “t”, 74.9% still used both products at 4-month follow-up, 20.1% change to exclusively smoking, and 4.9% had quit smoking (i.e., exclusively using e-cigarettes=3.4%; using neither e-cigarettes nor cigarettes=1.5%). Those who reported using e-cigarettes because they were less harmful to people around them (ARRR=0.67, 95% C.I. 0.48, 0.93), for enjoyment (ARRR=0.52, 95% C.I. 0.36, 0.76), eventually e-cigarettes will help me quit smoking (ARRR=0.65, 95% C.I. 0.46, 0.93), or to control weight (ARRR=0.46, 95% C.I. 0.24, 0.86) were less likely to stop using e-cigarettes and exclusively smoke at 4-month follow-up (Table 2). Furthermore, those who reported using e-cigarettes because of enjoyment were less likely to quit smoking at follow-up (ARRR=0.42, 95% C.I. 0.21, 0.84).
Table 2.
Crude and adjusted relative risk ratios* for product use transitions at four-month follow-up by reasons for using e-cigarettes among adults who smoked and used e-cigarettes (“dual use”) in Mexico, 2018–2021 (n=1653)
| Product use status at 4 month follow-up |
|||||||||
|---|---|---|---|---|---|---|---|---|---|
| Reasons for using e-cigarettes at time "t" | Continued dual use (74.9%) |
Exclusive smoking (20.1%) |
Quit smoking (exclusive e-cigarette use or quit both products) (4.9%) |
||||||
| % | % | RRR (95% C.I.) | ARRR (95% C.I.) a | % | RRR (95% C.I.) | ARRR (95% C.I.) a | |||
|
| |||||||||
| Less harmful to others | |||||||||
| No (n=1015) | 72.3 | 21.8 | reference | reference | 5.9 | reference | Reference | ||
| Yes (n=638) | 76.3 | 16.8 | 0.68 (0.47, 0.98) * | 0.67 (0.48, 0.93) * | 6.9 | 1.08 (0.53, 2.18) | 1.22 (0.67, 2.23) | ||
| Enjoyment | |||||||||
| No (n=1072) | 70.1 | 22.7 | reference | reference | 7.3 | reference | Reference | ||
| Yes (n=581) | 80.9 | 14.6 | 0.49 (0.33, 0.71) ** | 0.52 (0.36, 0.76) * | 4.5 | 0.39 (0.17, 0.86) * | 0.42 (0.21, 0.84) * | ||
| More socially acceptable | |||||||||
| No (n=1004) | 72.3 | 20.5 | reference | reference | 7.2 | reference | Reference | ||
| Yes (n=649) | 76.3 | 18.8 | 0.87 (0.62, 1.24) | 0.89 (0.65, 1.21) | 4.9 | 0.62 (0.30, 1.25) | 0.64 (0.35, 1.17) | ||
| Eventually, e-cigarettes will help me quit smoking | |||||||||
| No (n=1136) | 71.6 | 21.7 | reference | reference | 6.7 | reference | Reference | ||
| Yes (n=517) | 78.9 | 15.7 | 0.61 (0.41, 0.91) * | 0.65 (0.46, 0.93) * | 5.4 | 0.56 (0.27, 1.16) | 0.85 (0.46, 1.55) | ||
| Use in smokefree areas | |||||||||
| No (n=1170) | 72.9 | 20.5 | reference | reference | 6.6 | reference | Reference | ||
| Yes (n=483) | 76.2 | 18.2 | 1.01 (0.68, 1.50) | 1.07 (0.74, 1.54) | 5.6 | 1.11 (0.50, 2.45) | 1.48 (0.78, 2.81) | ||
| Helps cut down number of cigarettes | |||||||||
| No (n=1328) | 73.8 | 19.4 | reference | reference | 6.9 | reference | Reference | ||
| Yes (n=322) | 74.2 | 21.9 | 1.04 (0.66, 1.62) | 1.18 (0.78, 1.77) | 4.0 | 0.41 (0.14, 1.18) | 0.54 (0.23, 1.26) | ||
| E-cigarettes will help me stay quit from smoking | |||||||||
| No (n=1379) | 73.5 | 20.0 | reference | reference | 6.5 | reference | Reference | ||
| Yes (n=274) | 75.9 | 19.0 | 0.94 (0.59, 1.51) | 1.14 (0.72, 1.80) | 5.1 | 0.76 (0.29, 1.96) | 0.63 (0.25, 1.53) | ||
| Save money | |||||||||
| No (n=1409) | 73.5 | 19.7 | reference | reference | 6.7 | reference | Reference | ||
| Yes (n=244) | 75.8 | 20.5 | 1.04 (0.64, 1.69) | 1.41 (0.90, 2.21) | 3.7 | 0.55 (0.17, 1.75) | 0.82 (0.33, 2.03) | ||
| Control weight | |||||||||
| No (n=1511) | 72.7 | 20.6 | reference | reference | 6.8 | reference | Reference | ||
| Yes (n=142) | 86.6 | 12.0 | 0.34 (0.16, 0.70) * | 0.46 (0.24, 0.86) * | 1.4 | 0.08 (0.00, 0.90) * | 0.19 (0.03, 1.14) | ||
Random-effects multinomial models with continued dual use (i.e., no change) as the base outcome (Observations: n= 1653 individuals: n=904).
AOR adjusted for all variables in the table, as well as gender, age, educational attainment, household income, smoking and e-cigarette frequency, quit attempts, quit intentions, and the number of surveys to which participants had responded prior to time “t” (i.e., time in sample).
Bold text indicates statistical significance * (p < 0.05), ** (p< 0.001). CI = confidence interval; OR = odds ratio.
The three most prevalent reasons participants reported for stopping e-cigarette use (Figure 1) were that e-cigarettes were not satisfying (31.9%), cost too much (27.7%), and were not useful for stopping cigarette cravings (19.2%). At 4-month follow-up, 62.9% continued exclusively smoking and 37.1% had started using e-cigarettes again. In adjusted logistic regression models, those who reported that they had stopped using e-cigarettes because they were not satisfying were less likely to start using e-cigarettes again (AOR=0.58, 95% C.I. 0.34, 0.97; Table 3).
Table 3.
Crude and adjusted odds ratios for re-initiating e-cigarette use at four month follow-up by reasons for stopping e-cigarette use among adults who smoke and formerly used e-cigarettes in Mexico, 2018–2021
| Product use status at 4-month follow-up | |||||
|---|---|---|---|---|---|
|
| |||||
| Reasons for stopping e-cigarette use in time "t" | Continued exclusive smoking (62.9%) |
Re-initiated e-cigarette use (37.1%) |
|||
| % | % | OR (95% C.I.) | AOR (95% C.I.) a | ||
|
| |||||
| Not satisfying | |||||
| No (n=255) | 59.3 | 40.7 | reference | reference | |
| Yes (n=117) | 70.9 | 29.1 | 0.60 (0.38, 0.95) * | 0.58 (0.34, 0.97) * | |
| Devices cost too much | |||||
| No (n=252) | 63.5 | 36.5 | reference | reference | |
| Yes (n=120) | 61.7 | 38.3 | 1.03 (0.67, 1.59) | 0.88 (0.53, 1.45) | |
| Not useful to stop cravings | |||||
| No (n=286) | 61.9 | 38.1 | reference | reference | |
| Yes (n=86) | 66.3 | 33.7 | 0.85 (0.52, 1.39) | 0.88 (0.51, 1.51) | |
| Safety concerns | |||||
| No (n=303) | 63.7 | 36.3 | reference | reference | |
| Yes (n=69) | 59.4 | 40.6 | 1.29 (0.75, 2.22) | 1.07 (0.58, 1.98) | |
| Not helpful for quitting smoking | |||||
| No (n=306) | 62.4 | 37.6 | reference | reference | |
| Yes (n=66) | 65.2 | 34.9 | 0.84 (0.47, 1.49) | 0.94 (0.50, 1.79) | |
| E-liquids cost too much | |||||
| No (n=309) | 63.8 | 36.3 | reference | reference | |
| Yes (n=63) | 58.7 | 41.3 | 1.26 (0.74, 2.13) | 1.17 (0.58, 198) | |
| Uncomfortable to use in public | |||||
| No (n=330) | 63.3 | 36.7 | reference | reference | |
| Yes (n=42) | 59.5 | 40.5 | 1.12 (0.58, 2.18) | 1.17 (0.58, 2.38) | |
| Do not need to stay quit | |||||
| No (n=356) | 62.6 | 37.4 | reference | reference | |
| Yes (n=16) | 68.8 | 31.3 | 0.77 (0.25, 2.32) | 0.84 (0.22, 3.25) | |
| Negative experiences | |||||
| No (n=356) | 62.9 | 37.1 | reference | reference | |
| Yes (n=16) | 62.5 | 37.5 | 1.13 (0.42, 3.03) | 1.09 (0.37, 3.20) | |
| Becoming addicted | |||||
| No (n=352) | 63.4 | 36.6 | reference | reference | |
| Yes (n=20) | 55.0 | 45.0 | 1.43 (0.61, 3.33) | 1.33 (0.54, 3.25) | |
| Use e-cigarettes requires too much effort | |||||
| No (n=367) | 63.0 | 37.0 | reference | reference | |
| Yes (n=5) | 60.0 | 40.0 | 1.09 (0.18, 6.67) | 1.90 (0.30, 11.93) | |
Logistic regression models adjusted for repeated measures and weights, with continued exclusive smoking (i.e., no change) as the base outcome (Observations: n= 372, individuals: n=332).
AOR adjusted for all variables in the table as well as gender, age, educational attainment, household income, smoking frequency, quit attempts, quit intentions, and the number of surveys to which participants had responded prior to time “t” (i.e., time in sample).
Bold text indicates significant
(p < 0.05).CI = confidence interval; OR = odds ratio
Discussion
This study of Mexicans who smoke found that social reasons, such as reduced harm to others and social acceptability, as well as enjoyment, are the dominant reasons for using e-cigarettes. The high relative prevalence of using e-cigarettes because of their lower harm to others and their social acceptability is similar to studies across countries with and without e-cigarette bans,10,11 suggesting that the relative importance of these rationales does not depend on the regulatory environment. Concerns about secondhand smoke dangers in Mexico likely reflect both broader normative shifts related to smokefree policy implementation,23, 24 as well as exposure to marketing about e-cigarettes being less harmful than smoking,23 despite the e-cigarette ban.25 Nevertheless, the prevalence of using e-cigarettes because of reduced harm to others (40%) and their social acceptability (38%) is about half of that observed in the US, Canada, Australia and England,10,11 perhaps due to the relatively low frequency of e-cigarette and cigarette use in Mexico. Despite the different use pattern in Mexico, the prevalence of using e-cigarettes because they are enjoyable (34.2%) was similar to the one US study (36%),13 though much lower than in the aforementioned multiple country study.10 In the end, none of the reasons listed in our study reached a prevalence for above 40% among our participants. To better understand what drives Mexicans who smoke to use e-cigarettes, qualitative research may be necessary to explore in detail which other reasons that were not listed make e-cigarettes appealing to this population.
Social reasons for using e-cigarettes were unassociated with stopping either smoking or e-cigarette use, suggesting that such reasons may maintain concomitant use of both products. This contrasts with the one other longitudinal study, in the US, that found that citing the ability to use e-cigarettes in places where smoking is not allowed was inversely associated with stopping smoking.11 Is possible that the poor enforcement of smoke-free policies in Mexico 26 made this reason less important. Reviews find that people who smoke and start using e-cigarettes usually continue using both products.27 Indeed, our study suggests Mexicans are less likely to use e-cigarettes to reduce or quit smoking than because they enjoy using them. Furthermore, our sample used e-cigarettes infrequently, suggesting that they may not use them to replace cigarettes, perhaps because most Mexicans who smoke, including in our sample, do so less than daily. 28 As such, the distinctive pattern of cigarette and e-cigarette use in Mexico, along with weak enforcement of the e-cigarette ban, make it challenging to draw clear conclusions about any impacts of the regulatory context on our findings.
Among people who smoke and had formerly used e-cigarettes, the primary reason for discontinuing their use was because they did not find them satisfactory, suggesting that they were not good substitutes for cigarettes. Reporting that e-cigarettes were unsatisfactory was associated with lower likelihood of returning to use e-cigarettes at follow-up, consistent with a previous study.29 Research in other countries found that some people who smoke reported that e-cigarettes lack the same satisfaction29, 30 and stimulating sensorial characteristics (e.g., smell, flavor) of combustible cigarettes.31 Such concerns may be particularly prevalent in Mexico due to the illegal nature of the e-cigarette market, 32 which may result in lower quality devices and e-liquids, as well as mislabeled nicotine levels that could affect satisfaction and substitutability with cigarettes.
Our study found that the high perceived cost of e-cigarettes was the second most prevalent reason for stopping their use, although this reason was less prevalent in other studies.10 No systematic research has been conducted on e-cigarette prices in Mexico, though the ban could contribute to relatively high prices. For a first-time buyer or those who smoke less frequently, as is the dominant smoking pattern in Mexico, 21 purchasing an e-cigarette could be perceived as a relatively big expense for a product they are not sure they will enjoy or find satisfying enough to relieve their cravings. Studies of pricing are needed to provide more insights into these issues, especially as relatively cheap disposable e-cigarettes have come onto the market and appear to be displacing the mods, pens, and pod systems that were dominant during data collection for this study. 33
The prevalence of people who reported that they used e-cigarettes to control their weight was low (i.e., 9%), but they were less likely to return to exclusively smoking than those who did not use e-cigarettes to control their weight. Indeed, stronger expectancies that e-cigarettes help with weight control has been associated with dual use of both e-cigarettes and cigarettes.34 Prior research with the Mexican cohort on which the present study is based found that those who preferred cigarettes with flavor capsules (vs not) were more likely to believe that their cigarettes helped them to control their weight. 35 Indeed, the great range of flavors in the capsules that consumers can crush to flavor the smoke almost rivals the array of flavors for e-cigarettes. 36 While nicotine is a well-known appetite suppressor 37 more research is needed on the use of e-cigarettes – including the role of flavors – for weight control in adults, including whether this rationale for use influences transitions in smoking status.
This study has some limitations. Our study sample was recruited from an online panel for market research in Mexico with an over-representation of people in higher socioeconomic status groups, and people who smoke and use e-cigarettes, which tends to be younger, compared to people who exclusively smokes. 38 Population is not representative and a potential selection bias might had been introduced. To help reduce biases, our analyses integrated population weights, and prior research with this same population found that age and educational attainment were unassociated with smoking transitions, 17 suggesting that our results may not be seriously biased. Due to small sample sizes, our outcome of having stopped smoking combined those who, at follow-up, had transitioned to exclusively using e-cigarettes and to stopping use of cigarettes and e-cigarettes. As the reasons for using e-cigarettes may differ for these two groups, future research with larger sample sizes should evaluate these transitions separately. Nevertheless, our focus on stopping smoking is meaningful given greater, established harms for smoking.
Our assessment of changes in cigarette and e-cigarette use behaviors was limited to a 4-month follow-up period, which limited our ability to determine stable consumption patterns, as well as relapse or re-uptake of e-cigarettes and cigarettes. Indeed, 37% of our sample of people who smoke and formerly used e-cigarettes had returned to using e-cigarettes at follow-up, suggesting substantial instability to patterns of use. Studies with longer follow-up are needed, particularly for detecting predictors of smoking cessation. Furthermore, more in-depth research is needed to better understand the reasons for using or stopping use of e-cigarettes, especially the most dominant reasons for use (e.g., social reasons for use; unsatisfactory experiences with use), as this understanding could inform future intervention development. Finally, despite oversampling people who use e-cigarettes, our sample of people who formerly used e-cigarettes was relatively small, possibly impacting our results. Nevertheless, a major strength of the study is its longitudinal design for exploring how stated reasons for using or stopping use of e-cigarettes are associated with changes in product use.
What is already known on this topic
People who smoke have various reasons for using e-cigarettes, some of which are associated with changes in their nicotine product use behaviors.
The reasons for using or stopping use of e-cigarettes may differ across contexts where e-cigarettes are legal compared to illegal, as in Mexico.
What this study adds
In our sample, people who smoke and use e-cigarettes are less likely to return to exclusively smoking if they use e-cigarettes because they are less harmful to others, and if they believe e-cigarettes are helpful for quitting smoking or controlling weight.
People who smoke and use e-cigarettes because they find them enjoyable were less likely to either return to exclusively smoking or to quit smoking.
People who smoke and formerly used e-cigarettes but who stopped using them because they were not satisfactory were less likely to use e-cigarette again at follow-up.
How this study might affect research, practice, or policy
Future research should evaluate whether the characteristics of the products available in the illegal Mexican e-cigarette market – as well as in other illegal markets – help account for the reasons why people use e-cigarettes and trajectories of nicotine product use.
Funding
This study was supported by Fogarty International Center of the National Institutes of Health under award number R01 TW010652. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Footnotes
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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