Context: Overweight is a strong risk factor for gestational diabetes (GDM), and both states indicate increased risk for subsequent metabolic syndrome. Data separating effects of overweight and GDM on risk for metabolic diseases are limited.
Objective: The aim of the study was to evaluate prepregnancy overweight and GDM as determinants of risk for subsequent diabetes and hypertension.
Design: Population-based data from the Northern Finland Birth Cohort 1986 were compounded with register-based data on diagnosis of diabetes and hypertension.
Setting: The study was conducted in Northern Finland.
Participants: We studied: 1) normal-weight women with GDM (n = 70); 2) overweight women with GDM (n = 54); 3) normal-weight (n = 768) and 4) overweight (n = 250) women with risk factors for GDM but normal oral glucose tolerance test results; and 5) women with no risk factors for GDM (n = 5341).
Main outcome measures: We measured cumulative incidence of diabetes and hypertension, hazard ratio (HR), and population-attributable fraction (PAF) for determinants of risk.
Results: The cumulative incidence of diagnosed diabetes and hypertension in the whole study population was 1.3 and 7.5%, respectively. Concomitant overweight and GDM indicated high risks for diabetes (HR, 47.24; PAF, 15.8%) and hypertension (HR, 9.16; PAF, 4.4%). Even when the OGTT in pregnancy was normal, prepregnancy overweight associated with risks for diabetes (HR, 12.63; PAF, 22.2%) and hypertension (HR, 2.86; PAF, 6.0%). In normal-weight women, GDM indicated risk for diabetes (HR, 10.61; PAF, 5.2%) but not for hypertension.
Conclusions: Prepregnancy overweight is an essential risk factor for subsequent diabetes and hypertension, especially when combined with GDM.