Long-term effects of gestational diabetes on bone mineral density and fracture risk: Analysis of the Norfolk cohort of the European Prospective Investigation into Cancer (EPIC-Norfolk) population-based study

Objectives: Gestational diabetes mellitus (GDM) is a common pregnancy complication. This study aims to investigate the association between a history of GDM and bone mineral density (BMD), fractures, and falls in later life. Study design: We used data from the Norfolk cohort of the European Prospective Investigation into Cancer (EPIC-Norfolk) where BMD at calcaneum was measured at second health check (1997-2000) using broadband ultrasound attenuation (BUA) and velocity of sound (VOS) in 7,515 women. Fractures and falls were documented from hospital admissions data via linkage with ENCORE (East Norfolk Commission Record) and history of GDM from health questionnaires at baseline. We examined the relationship between GDM and BUA/VOS using linear regression. Cox regression was used to estimate hazard ratios (HRs) for incident fractures and falls, controlling for age, BMI, smoking status, physical activity, area deprivation, self-reported stroke, use of diuretics, calcium and vitamin D supplements, social class and education, statin and total blood cholesterol, prevalent diabetes, hormone therapy and menopausal status. Results: History of GDM (n = 183) was not statistically significantly associated with BUA/VOS in fully adjusted linear regression models with unstandardised beta coefficients (standard error):-0.37 (1.40) and-5.41 (3.48). GDM was significantly (p < 0.05) associated with risk of hip and all fractures, fully adjusted HRs(95 %CI) 2.46 (1.54-3.92) and 1.60(1.09-2.35), respectively. Median follow-up from first live birth to date of admission was 53 and 52 years, respectively Conclusion: There was an association between history of GDM and risk of any fracture as well as hip fracture specifically. Further research is required to confirm this.