Short birth intervals and early menopause in sub-Saharan Africa: a multicountry analysis of physiological and psychosocial pathways in reproductive aging

Background Early menopause (before age 45) significantly elevates risks for cardiovascular disease, osteoporosis, diabetes, cognitive decline, and overall mortality. While previous research predominantly focused on genetic and socioeconomic determinants in high-income countries, reproductive factors such as birth spacing remain understudied, especially in resource-limited regions like sub-Saharan Africa (SSA), where short birth intervals (SBIs) are prevalent. Methods This study utilized pooled data from Demographic and Health Surveys (DHS) across 26 SSA countries (2015–2022), involving 120,912 women aged 30–49 years. Multilevel logistic regression models assessed associations between birth intervals and early menopause. Country-specific analyses and quantile regressions further evaluated the dose-response relationship and effects on age at menopause, respectively. Mediation analysis using the Karlson–Holm–Breen (KHB) method explored pathological, metabolic, nutritional, and psychological pathways. Findings Compared to intervals of ≥ 60 months, birth intervals ≤ 17 months and 18–23 months increased early menopause odds by 33% (AOR = 1·33, 95% CI: 1·18–1·49) and 22% (AOR = 1·22, 95% CI: 1·09–1·37), respectively. A dose-response relationship emerged: multiple very short intervals (< 18 months) substantially heightened risk. Quantile regression confirmed SBIs significantly lowered menopause age, particularly at lower quantiles. Pathological (pregnancy loss), metabolic (obesity), nutritional (underweight), and psychological (Mental Disease) factors significantly mediated this association. Interpretation Our findings identify SBIs as a modifiable reproductive risk factor for early menopause in SSA, underscoring the necessity of integrating optimal birth spacing into lifelong women’s health strategies. Enhancing access to family planning, nutritional support, and psychosocial interventions could mitigate associated chronic disease risks and safeguard women’s long-term well-being. Funding None