Prospective cohort study of exposure to tobacco imagery in popular films and smoking uptake among children in southern India

BACKGROUND: Exposure to tobacco imagery in films causes young people to start smoking. Popular Indian films contain high levels of tobacco imagery, but those that do are required by law to display onscreen health warnings when smoking imagery occurs and to include other health promotion messaging before and during the film. We report a prospective cohort study of incident smoking in relation to exposure to film tobacco imagery and anti-tobacco messaging in a cohort of children in southern India. METHODS: We carried out a one-year longitudinal follow up questionnaire survey in 2018 of a cohort of 39,282 students in grades 6, 7 and 8 (aged between 10 and 15 years) in schools in the Udupi district of Karnataka State in India who participated in a 2017 cross-sectional study of exposure to smoking in films and ever smoking status. RESULTS: We obtained usable linked data in 2018 from 33,725 of the 39,282 (86%) participants with data from 2017. Incident smoking was reported by 382 (1.1%) participants. After adjusting for age, sex and common confounders significantly associated with incident smoking there was no significant independent effect of exposure to film smoking, either as a binary (Odds Ratio 1.6, 95% Confidence Interval (CI) 0.5 to 4.9) or as a graded variable, on smoking uptake. An exploratory analysis indicated that the presence of on-screen health warnings that complied fully with Indian law was associated with a significantly lower odds of smoking uptake (Odds Ratio 0.8 (0.6 to 1.0, p = 0.031) relative to the same exposure sustained in absence of compliant warnings. CONCLUSION: Exposure to tobacco imagery in Indian films was not associated with a significantly increased risk of incident smoking in South Indian children. While it is possible that this finding is a false negative, it is also possible that the effect of film exposure has been attenuated by the presence of on-screen health warnings or other Indian tobacco-free film rules. Our findings therefore support the wider implementation of similar tobacco-free film measures in other countries.