Tobacco is the single most common cause of preventable cancers, hypertension and chronic obstructive airways diseases However, we are unaware of any studies that have assessed predictors of ETS among adolescents in Mongolia.

In the present study we report the prevalence of ETS exposure and predictors of exposure among school going adolescents in Mongolia. We used the 2003 Global Youth Tobacco Survey data.

» Materials and Methods

This was a cross sectional study conducted among 13-15 yr old school-going adolescents in Mongolia in 2003. All students in the eligible classes were invited to participate regardless of their actual ages. A two-stage clustered sampling approach was used in which the primary sampling units were schools. In the second stage, eligible classes within the school were randomly selected. All students within the selected schools were eligible to participate in the study.

Study participants self-completed a modified GYTS questionnaire according to the procedures of the GYTS. The GYTS questionnaire comprises some standardized core questions. Country teams may also include a limited number of questions to collect information that may be specific to their area. Completion of the questionnaire is estimated to take about 40 minutes. The following questions were asked to collect information on parental smoking and exposure to ETS: Do your parents smoke? Do any of your closest friends smoke cigarettes? During the past 7 days, on how many days have people smoked in your home, in your presence? During the past 7 days on how many days have people smoked in your presence, in places other than in your home?

Permission to conduct the study was obtained from the Ministry of Education. Eligible students were informed that they were free not to participate. Questionnaires were filled in anonymously.

» Results

Socio-demographic characteristics of study participants

Of the 4105 adolescents who participated in the Mongolian GYTS in 2003, 3507 were nonsmokers. presents selected demographic characteristics of the 3507 nonsmoker Mongolian adolescents. Most of the sample (median age: 14 yr) was either female (58.2%), 14 yr old (30.3%), with a smoking father (48.0%), and with nonsmoking friends (52.5%).

Prevalence and predictors of exposure to environmental tobacco smoke

indicates that the prevalence of ETS exposure was similar at home for both males and females (62.3% and 62.0% respectively), but males had a higher prevalence of exposure to ETS outside of the home than females (50.7% and 42.4% respectively (p <0.001). The prevalence of ETS exposure increased with age (p-trend < 0.05).

. Having some smoking friends was associated with more than two times the odds of ETS exposure. The odds of ETS exposure increased with age (p-trend <0.001). Females aged 15 yr of age had a 61% increase in the odds of ETS exposure compared to those who were 11-12 yr old. Among males, those who were 16 year of age or older had 91% increase in the odds of ETS exposure compared to 11-12 year old boys. There was a positive correlation between the prevalence of active and passive smoking (r=0.9; p<0.05).

» Discussion

The present study found 73.9% prevalence of ETS among males and 71.7% among adolescent females in Mongolia. The small non-statistically different prevalence between males and females was largely contributed by difference in out-of-home exposures where males had significantly higher exposure than females. This could be explained by socio-cultural situations where males may be more likely to spend time than females outside of the home in places where smoking is likely to occur.

Li and Wang have reported that among adolescents in Taiwan, females were more likely to purposively avoid exposure to ETS than males. Negative attitudes towards smoking by females were thought to have contributed toward such behavior. We do not know to what extent and in what situations adolescents may purposively avoid being exposed to ETS.

Preston et al have reported that exposure to ETS by an adolescent depends on the identity of smoker and the relationship to the adolescent, age of the adolescent and parental smoking.

We also found that increasing age was associated with higher likelihood of being exposed to environmental tobacco smoke in both males and females. This situation could occur as a result of older children having greater opportunity to be outside home but in places where smoking is likely to occur.

The present study had several limitations. Firstly we did not assess biomarkers of tobacco smoke exposure such as cotinine levels in study participants who reported exposure to ETS. As the study participants were asked to report exposure in the past 7 day exposure this would have been possible to detect in urine. However, the present study used a standardized questionnaire that enables within country and cross-country comparisons of ETS exposure. Secondly, the sample was recruited from school-going adolescents and therefore may not be representative of all adolescents in the study area. Also data were collected from students who were available in school on the day of the survey. No attempt was made to have questionnaire completed by students who were absent. Finally, this was a self-completed questionnaire. There is therefore a potential for mis-reporting by study participants.

» Conclusion

The adverse effects of environmental tobacco smoking among adolescents have been described earlier. Public health interventions aimed to limit ETS exposure among adolescents should consider both the home and the out of home environment. Knowledge about who the smoker is, the relationship with the adolescents, where and when smoking occurs, are likely to facilitate planning and delivery of effective ETS prevention programs.

Acknowledgements

The GYTS is a collaborative project of WHO/CDC/participating countries. Analyses of GYTS data are not necessarily endorsed by the WHO/CDC/participating countries. We are thankful to the study participants and research assistants.