Substance use outcomes in first- and second- generation of immigrants: Systematic review and meta-analysis

Understanding substance use outcomes across different immigrant populations is critical for informing targeted public health interventions. This systematic review aims to consolidate current findings on the prevalence of substance use among immigrants, focusing on generational differences, to understand substance use trends and their evolution within immigrant communities.

We systematically searched PubMed, PsycINFO, Web of Science, Medline, Cochrane, and Embase for cross-sectional observational studies. We included studies published between 1990 and 2026, examining substance use prevalence among first generation immigrants and second-generation immigrants. Odds ratios were calculated using random-effects models. Heterogeneity was assessed through I², and potential publication bias was evaluated using Egger's test and funnel plots. Subgroup analyses and meta-regressions were performed to explore heterogeneity.

From a total of 157,426 screened articles, 51 studies were included in the final analysis, covering 4,933,781 individuals from more than 9 countries. For alcohol, the OR was 1.68 (95% CI: 1.38; 2.04) for consumption, 2.10 (95% CI: 1.68; 2.64) for dependence and 2.08 (95% CI: 1.83; 2.37) for abuse. Regarding drug use, overall OR was 2.18 (95% CI: 1.81; 2.63) for consumption, 4.32 (95% CI: 3.48; 5.37) for abuse and 4.21 (95% CI: 3.19; 5.55) for dependence. OR for cannabis use was 3.8 (95% CI: 2.12; 6.92) whereas for tobacco use, no significant difference was found (OR 1.61; 95% CI: 0.98; 2.64).

The findings highlight generational differences in substance use outcomes, with second-generation individuals often displaying higher usage rates compared to the first-generation. These results underscore the need for culturally tailored intervention and prevention strategies.