RESUMO
Background: Cigarette and alcohol use are the most common causes of noncommunicable diseases. Studies related to cigarette and alcohol use among Nigerian adolescents have shown increases in the habits and require urgent intervention. Nationally representative data is needed to develop effective national policies and interventions, but this is lacking. Hence, this study aimed to provide nationally representative empiric information about cigarette and alcohol use prevalence and predictors among Nigerian secondary school students. Methods: This study included 2,530 Nigerian students in Nigeria from five of the six geopolitical zones in Nigeria. A self-administered questionnaire was used to obtain information about the participants' sociodemographic and school-based characteristics, cigarette and alcohol use status, and harm perception of tobacco and alcohol use. Data were analysed with SPSS version 25 at p<0.05. Results: Participants' mean age (±SD) was 16.34 (±2.0) years. The prevalences (95%CI) for ever-cigarette and current-cigarette smoking were 11.1% (95%CI:9.9-12.4) and 8.4% (95%CI:7.3-9.5), respectively. While 21.0% (95%CI:19.4-22.7) and 15.6% (14.2-17.1) were the prevalences for lifetime and current alcohol use, respectively. The predictors of current cigarette smoking were studying in northern-Nigeria (aOR:1.94;95%CI:1.10-3.44), attending private-schools (aOR:1.56;95%CI:1.03-2.38), boarding-student (aOR:1.75;95% CI:1.15-2.69), male-gender (aOR:3.03; 95%CI:1.80-5.10), current alcohol use (aOR:12.50;95%CI:8.70-18.18), having no (aOR:2.59;95%CI:1.58-4.26) or low tobacco harm perception (aOR:2.04;95%CI:1.18-3.53). The predictors of current alcohol use were male (aOR:1.32; 95%CI:1.01-1.72) and current cigarette smoking (aOR:12.5;95%CI:8.77-17.86). Conclusion: The prevalences of cigarette and alcohol use were high among Nigerian secondary school students, and both habits were strongly associated. Their predictors were school-related factors, sociocultural characteristics, and tobacco harm perception.