Risk factors of osteoporosis in post-gastrectomy gastric cancer patients: a systematic review and meta-analysis

Osteoporosis is a highly prevalent and serious complication among long-term survivors of gastric cancer (GC) after gastrectomy. However, the key risk factors predisposing patients to this condition have not been systematically assessed. PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched for observational studies from inception until July 21, 2025, to collect data on the risk factors for osteoporosis. Two independent reviewers appraised the methodological quality using the Newcastle-Ottawa Scale. Fixed-effects and random-effects models were used to calculate the odds ratio (OR) and 95% confidence interval (CI) for each factor. Eleven studies (covering 232,814 subjects) that reported clear associations were included in the analysis, the following risk factors were associated with osteoporosis in post-gastrectomy GC patients: female sex (number of studies [n] = 6; OR: 2.30, 95% CI: 1.50-3.51, p < 0.001), older age (n = 4; OR: 1.06, 95% CI: 1.03-1.09, p < 0.001), diabetes mellitus (n = 5; OR: 1.16, 95% CI: 1.07-1.25, p < 0.001), anemia (n = 2; OR: 2.20, 95% CI: 1.51-3.19, p < 0.001), elevated alkaline phosphatase (ALP) (n = 2; OR: 3.51, 95% CI: 1.35-9.12, p = 0.010), and Charlson Comorbidity Index score (CCI) > 3 (n = 2; OR: 1.24, 95% CI: 1.08-1.41, p = 0.002). Urban residence was associated with a modest protective effect (n = 2; HR: 0.87, 95% CI: 0.78-0.97, p = 0.013).