A meta-analysis of the incidence proportion of obesity and associated risk factors in patients with schizophrenia

Objective This meta-analysis aimed to investigate the incidence proportion of obesity and its influencing factors in patients with schizophrenia (SCH). Methods A comprehensive literature search was conducted using a combination of MeSH subject headings and free-text terms across multiple databases, including PubMed, Web of Science, Embase, Cochrane Library, CNKI, Wanfang Data, VIP Database, and SinoMed. The search covered all publications up to May 26, 2025. Meta-analyses were performed using RevMan 5.4 and Stata 18.0 software. Results A total of 18 studies involving 9, 351 patients with SCH were included in the analysis. This meta-analysis revealed that the incidence proportion of obesity in patients with SCH was 33.0%. Additionally, the following factors were significantly associated with an elevated risk of obesity in this population ( P < 0.05): female sex ( OR = 1.14, 95% CI = 1.10–1.20), elevated FG ( OR = 1.08, 95% CI = 1.04–1.12), diabetes ( OR = 2.36, 95% CI = 1.79–3.10), elevated TG ( OR = 1.13, 95% CI = 1.08–1.18), high LDL ( OR = 1.88, 95% CI = 1.45–2.44), olanzapine use ( OR = 7.40, 95% CI = 4.98–11.00), combined antipsychotic therapy ( OR = 3.19, 95% CI = 2.31–4.41), use of typical antipsychotics ( OR = 1.46, 95% CI = 1.18–1.82), use of atypical antipsychotics ( OR = 1.70, 95% CI = 1.42–2.03), high red blood cell count ( OR = 2.80, 95% CI = 1.60–4.90), and low HDL ( OR = 1.75, 95% CI = 1.41–2.16). Conclusion Current evidence indicates that the major risk factors for obesity in patients with SCH include female sex, elevated FG, diabetes, high TG levels, elevated LDL, use of olanzapine, combined antipsychotic treatment, use of typical antipsychotics, use of atypical antipsychotics, higher red blood cell count, and reduced HDL levels. Clinicians should implement early screening and targeted interventions to mitigate the development of obesity in this population, thereby improving their overall quality of life. Systematic Review Registration https://www.crd.york.ac.uk/PROSPERO/ , identifier CRD420251121298.