The relationship between sexual function and body mass index in postmenopausal women: a systematic review and meta-analysis

Background Female sexual dysfunction (FSD) is a common and multifactorial problem in postmenopausal women that affects their quality of life. Given the increasing global prevalence of obesity and the potential role of body mass index (BMI) as a contributing factor, this systematic review and meta-analysis was conducted to determine the relationship between BMI and sexual function in postmenopausal women. Methods This systematic review and meta-analysis were performed according to PRISMA guidelines by searching international (PubMed, Scopus, Web of Science, ScienceDirect, Embase, Cochrane) and Iranian (IranMedex, Magiran, IranDoc, SID) databases up to August 2026. Inclusion criteria consisted of observational studies (cross section, cohort, and case–control) examining the association between BMI and sexual function in postmenopausal women. No restrictions were applied regarding language or publication date. Study quality was assessed using Joanna Briggs Institute (JBI) checklists. Meta-analysis was performed using a random-effects model with restricted maximum likelihood (REML), and between-study heterogeneity was assessed using Cochran’s Q test and the I2 statistic; publication bias was evaluated using Egger’s regression test. Results Following an updated search, 25 studies met the eligibility criteria and were included in the qualitative synthesis. Of these, 13 studies (52.0%) exclusively enrolled postmenopausal women, while the remaining studies included mixed menopausal populations. These studies were conducted across 14 different countries between 1996 and 2026. The main instrument for assessing sexual function was the FSFI questionnaire, which was used in ten studies. Other studies utilized instruments, including Cervantes, MHR–QOL, McCoy, CSFQ-14, SAQ, Modified Kupperman Menopausal Index (mKI), or researcher-designed questionnaires. The systematic review of 25 studies showed that 19 studies (76.0%) reported a statistically significant inverse association between BMI and sexual function, particularly in domains of satisfaction, desire, and arousal. However, three studies (12.0%) reported no significant relationship, and three studies (12.0%) found a positive relationship. The meta-analysis of four studies showed no significant pooled association between overweight BMI and sexual dysfunction (OR = 1.00, 95% CI 0.81–1.24). Conclusions The findings of this systematic review indicate that most studies reported a negative association between higher BMI and reduced sexual function in postmenopausal women. However, the meta-analysis—based on a limited number of eligible studies—did not show a significant pooled effect. These results suggest that although elevated BMI is frequently correlated with poorer sexual function, the current evidence is insufficient to support BMI as an independent causal factor. Additional high-quality longitudinal studies are needed to clarify the nature and direction of this relationship.