Using the theory of triadic influence to establish the trend in tobacco use and its correlates among in-school adolescents in Tanzania (2003–2016): findings from the global youth tobacco survey

Smoking among adolescents in schools is a major global public health concern. The prevalence and factors associated with cigarette smoking in Tanzania have not been studied over time. Therefore, this study aims to explore trends and correlates associated with tobacco use among in-school adolescents in Tanzania, guided by the Theory of Triadic Influence (TTI). This study utilized a pooled weighted sample of 13,610 adolescents, derived from three rounds of the 2003, 2008, and 2016 Global Youth Tobacco Surveys. Given the complex survey design, weighted binary logistic regression was employed for the analysis, using STATA version 18.5. Statistical significance at a p-value of < 0.05. The prevalence of tobacco use was 3.3%, and the trend was 8.3% in 2003, 9.3% in 2008, and 2% in 2016. Compared to adolescents aged 11 years and younger, those aged 12–13 (AOR:0.47, [95% CI: 0.26–0.83]) and 14–15 (AOR:0.46, [95% CI: 0.26–0.85]) had lower odds of tobacco use. Males had 2 times higher odds of using tobacco (AOR:2.03, [95% CI: 1.43–2.87]) compared to females. Adolescents in class 7 (AOR:0.65, [95% CI: 0.44–0.96]) had lower odds of using tobacco compared to other classes. In social situation or context stream factors, adolescents whose parents’ smoking status was unknown had 3 times (AOR:3.36, [95% CI: 2.02–5.62]) higher odds of tobacco use compared to those with non-smoking parents. Adolescents with close friends who smoke had significantly higher odds of tobacco use compared to adolescents with no smoking friends. Compared to adolescents whose best friends did not offer cigarettes, those who responded probably not (AOR:2.48 [95% CI: 1.16–5.30]), probably yes (AOR:2.70, [95% CI: 1.57–4.64]), and definitely yes (AOR:3.49, [95% CI: 1.54–7.92]) had significantly higher odds of tobacco use in adjusted analysis. Regarding environmental stream factors, compared to the counterpart, both adolescents who were refused cigarettes due to age (AOR:4.11, [95% CI: 2.47–6.86]) and those who were sold cigarettes regardless of age (AOR:3.36, [95% CI: 2.02–5.62]) had higher odds of tobacco use. Those with no exposure had higher odds of tobacco use (AOR:2.32, [95% CI: 1.45–3.98]). Adolescents who were not sure of being taught the dangers of smoking at school had higher odds of tobacco use compared to those who were taught (AOR:2.41, [95% CI: 1.45–3.98]). This study established the prevalence, trends, and correlates of tobacco use which underscore the importance of early interventions, the influence of peers and family, and the need for comprehensive tobacco control strategies that address individual, social, and environmental factors. Recommendations include strengthening school-based education, enforcing age restrictions, and designing targeted media campaigns.