Social inequalities in gestational diabetes prevalence and complication burden: a nationwide Swedish cohort study

CONTEXT: While studies from other settings have shown associations between social determinants of health (SDOH) and GDM, evidence remains limited in high-income, equity-oriented healthcare settings. OBJECTIVE: To examine the association between SDOH, GDM and GDM-related complications in Sweden. DESIGN: Retrospective cohort study. SETTING: Nationwide registry data linked across multiple population-based registries. PARTICIPANTS: 938,798 singleton pregnancies. EXPOSURES: GDM, with effect modification by region of birth, education and income. MAIN OUTCOMES: Number of pregnancy, obstetric, postpartum and neonatal complications. RESULTS: The prevalence of GDM increased from 1.5% to 6.6% between 2015-2023, with the steepest increases observed among individuals with foreign-born origin, lower education, and lower income. While income did not show evidence of interaction with GDM regarding the number of complications, the associations between GDM and both pregnancy-related and obstetric complications varied across educational attainment groups, with larger relative associations observed among women with lower education (pinteraction = 0.029 and 0.038, respectively).The associations between GDM and several adverse outcomes differed by nativity status. For example, GDM was associated with 71% higher odds of obstetric complications among Swedish-born women (OR, 1.71; 95% CI, 1.68-1.85), whereas the corresponding associations were significantly weaker among women born in Africa (1.34; 1.17-1.52) and the Eastern Mediterranean region (1.44; 1.34-1.56).However, absolute risks were not uniformly lower among foreign-born women with GDM. Notably, women born in Africa and South-East Asia had higher absolute risks of obstetric complications compared with Swedish-born without GDM. CONCLUSIONS: Disparities in GDM prevalence across all three SDOH indicators underscore the importance of considering sociodemographic factors in prevention efforts. Variation in GDM-associated risks by educational level and region of birth warrant further investigation to ensure equitable care.