Background Gambling behaviours have become of increased public health interest, but data on prevalence remain scarce. In this study, we aimed to estimate for adults and adolescents the prevalence of any gambling activity, the prevalence of engaging in specific gambling activities, the prevalence of any risk gambling and problematic gambling, and the prevalence of any risk and problematic gambling by gambling activity.

Methods We performed a systematic review and meta-analysis. We systematically searched for peer-reviewed literature (on MEDLINE, Embase, and PsycInfo) and grey literature to identify papers published between Jan 1, 2010, and March 4, 2024. We searched for any gambling, including engagement with individual gambling activities, and problematic gambling data among adults and adolescents. We included papers that reported the prevalence or proportion of a gambling outcome of interest. We excluded papers of non-original data or based on a biased sample. Data were extracted into a bespoke Microsoft Access database, with the Joanna Briggs Institute Critical Appraisal Tool used to identify the risk of bias for each sample. Representative population survey estimates were firstly meta-analysed into country-level prevalence estimates, using metaprop, of any gambling, any risk gambling, problematic gambling, and by gambling activity. Secondly, population-weighted regional-level and global estimates were generated for any gambling, any risk gambling, problematic gambling, and specific gambling activity. This review is registered on PROSPERO (CRD42021251835).

Findings We screened 3692 reports, with 380 representative unique samples, in 68 countries and territories. Overall, the included samples consisted of slightly more men or male individuals, with a mean age of 29·72 years, and most samples identified were from high-income countries. Of these samples, 366 were included in the meta-analysis. Globally, 46·2% (95% CI 41·7–50·8) of adults and 17·9% (14·8–21·2) of adolescents had gambled in the past 12 months. Rates of gambling were higher among men (49·1%; 45·5–52·6) than women (37·4%; 32·0–42·5). Among adults, 8·7% (6·6–11·3) were classified as engaging in any risk gambling, and 1·41% (1·06–1·84) were engaging in problematic gambling. Among adults, rates of problematic gambling were greatest among online casino or slots gambling (15·8%; 10·7–21·6). There were few data reported on any risk and problematic gambling among adolescent samples.