A dose-response meta-analysis on the relationship between average amount of alcohol consumed and death by suicide

Background: To determine whether sub-clinical levels of drinking may contribute to suicide risk, and whether the risk differs by sex, we aimed to evaluate the relationship between average amount of alcohol consumed per day and death by suicide. Methods: A systematic literature search was performed in Embase, Medline, PsycINFO, PubMed, and Web of Science from database inception up to April 27, 2022. The search strategies incorporated a combination of medical subject headings and keywords for "alcohol use" and "suicide". One-stage dose-response meta-analyses using a restricted maximum likelihood random-effect estimator were conducted to explore the relationship between average alcohol volume consumed and suicide, by sex. Three different shapes of the dose-response relationship-linear (on the log-scale), quadratic, and restrictive cubic splines-were tested. Results: A total of eight studies were included (three studies for females (n=781,205), and eight studies for males (n=1,215,772)). A linear dose-response relationship between average alcohol volume consumed and the log-risk of suicide was identified for both males and females. For males and females, a relative risk (RR) of 1.11 (95% CI: 1.05, 1.18) and 1.64 (95% CI: 1.07, 2.51) for suicide when consuming an average of 10 g of pure alcohol per day compared to lifetime abstention, 1.38 (95% CI: 1.14, 1.66) and 4.39 (95% CI: 1.21, 15.88) for 30 g/day, and 1.71 (95% CI: 1.25, 2.33) and 11.75 (95% CI: 1.38, 100.33) for 50 g/day, respectively. Conclusions: As consumption increases, the risk of suicide increases proportionally. The risk of suicide associated with average daily alcohol consumption may be elevated for females, compared with males. Albeit, more research is needed, particularly among females.