Purpose: Compared to medical treatment, bariatric surgery reduces long-term mortality in persons with obesity. Some studies indicate that the effect only applies to patients above median age of cohorts, not to younger patients. Our objective was to assess the role of age in the reduction of mortality (global mortality and mortality for specific causes) through bariatric surgery.

Materials and methods: Data sources: PubMed, Cochrane Library, MEDLINE, and Embase.

Study selection: studies reporting mortality in relation to median age of patients.

Data extraction and synthesis: pooled random effects of estimates of the risk of mortality in participants undergoing surgery compared with controls, as function of median age.

Results: Mortality was lower in patients undergoing surgery than in controls (OR = 0.29, 95% CI 0.17-0.49). Below median age, the difference between surgery patients and controls was nonsignificant (OR = 0.78, 95% CI 0.57-1.06). Above median age, the difference was significant (OR = 0.23, 95% CI 0.12-0.44). In a subset of 5 studies, deaths due to various causes were less, and external causes-related deaths were more frequent in surgery than in controls. Below median age, deaths due to CVD were less frequent in surgery than in controls. Above median age, total deaths and deaths due to various causes (cardiovascular, diabetes, cancer, and other causes) were less in surgery than in controls. Publication bias was absent.

Conclusion: Compared with controls, bariatric surgery reduces long-term global mortality only above median age, not below median age. Also mortality due to specific causes is mainly reduced in persons above median age.