Background Alcohol use is often initiated during the adolescent years with significant health and economic consequences.

Objective We examined the prevalence and costs of of alcohol use and alcohol-related injuries among adolescents. Findings are part of a larger study on health-risk behaviours among adolescents in Oyo state Nigeria.

Methods In this cross-sectional study, 1142 adolescents were selected via multi-stage sampling. Information on socio-demographic characteristics, alcohol use, weekly expenditure on alcohol and costs of managing an alcohol-related injury within 12-months of the study were obtained. Costs are reported in 2020 prices in Nigerian Naira (NGN) and the US Dollar equivalent (Central Bank of Nigeria exchange rate in 2020 = NGN360.50: 1USD).

Results The adolescents’ mean age was 16±1.8 years, 56.0% were male and 51.1% were currently schooling. Almost a quarter (271), had ever taken more than a few sips of alcohol. The mean age when they had their first drink was 14.5±2.4 years; median:15 (range 5 -19) years. One hundred and thirty-seven (12.0%) adolescents had at least a drink of alcohol within 30 days of the study (current drinkers) of which 54 (39.4%) took 5 or more drinks per sitting. Males were three times more likely to be current consumers of alcohol than females (OR = 3.11; CI = 1.87 – 5.15). The mean amount spent purchasing alcohol per week was N1229.072±5.60 (US$3.41±0.02). Twenty-two of the 271 adolescents who had ever taken alcohol were involved in a physical fight while drunk at least once within 12-months of the study of whom 36.4% had been involved in 5 or more fights. Twelve (54.5%) adolescents sustained injuries requiring treatment while fighting. Mean cost of treatment was N4251.84±7.89 (US$11.79±0.02).

Conclusion Almost a quarter of the adolescents had ever taken alcohol with age at first consumption as low as five years. Costs of alcohol consumption and related injuries were substantial especially as these costs could have been put to more productive use. Further, treatment costs are frequently borne out-of-pocket. Interventions to prevent initiation of alcohol consumption in the study area can be useful in preventing alcohol use initiation, alcohol-related injuries and attendant economic costs.