RESUMO
BACKGROUND: Substance use among school-going adolescents increases the risk of developing mental disorders, addiction, and substance use disorders. These may lead to poor academic performance and reduced productivity, which affects adolescent lives. The study aimed to determine the prevalence of substance use and associated factors among secondary school adolescents in the Kilimanjaro region, northern Tanzania. METHODOLOGY: The study used secondary data from a cross-sectional survey of adolescents aged 10-19 years from public secondary schools in the Kilimanjaro Region, northern Tanzania. Substance use was measured using the Global School Health Survey (GSHS) questionnaire. Categorical variables were summarized using frequencies and percentages, while numerical variables used mean and standard deviation. Multivariable logistic regression models were used to obtain odds ratios (OR) and 95% confidence intervals (CI) to determine risk factors associated with lifetime and current (within the past 30 days preceding the survey) substance use. RESULTS: The lifetime and current prevalence of substance use among 3224 adolescents was 19.7% and 12.8%, respectively, while alcohol and cigarettes were commonly used. Female adolescents had lower odds of current substance use (OR = 0.63, 95%CI 0.50-0.80). Higher odds of current substance use were among adolescents who have ever had sex (OR = 4.31, 95%CI 3.25-5.71), ever engaged in a physical fight (OR = 2.19, 95%CI 1.73-2.78), ever been bullied (OR = 1.55, 95%CI 1.16-2.05), always seen alcohol advertisements (OR = 1.87, 95%CI 1.37-2.53), and adolescents whose parent/guardians rarely understood their problems (OR = 1.38, 95% CI = 1.03-1.85). Adolescents whose classmates always showed social support had lower odds of current substance use (AOR = 0.71, 95%CI 0.53-0.97). Similar factors were associated with lifetime substance users. CONCLUSION: The study reflects a high prevalence of substance use among adolescents in the Kilimanjaro region. Alcohol and cigarette are the most prevalent substances used. Regulatory measures are essential to limit alcohol advertisements that are media portrayed. Efforts are needed to reduce risk behaviors, such as physical violence and bullying, through peer support groups/clubs in school environments.