Gestational diabetes mellitus in Sweden : screening, outcomes and consequences

Sammanfattning: Gestational diabetes mellitus (GDM) has been a controversial issue nationally and internationally for decades. In the studies presented in this thesis, different aspects of GDM were analysed, including screening methods, national outcomes in Sweden, the influence of ethnicity, and future morbidity for women with GDM.Paper I: In a population-based cross-sectional study (N = 3616) fasting capillary glucose was analysed as a screening test for GDM. For fasting capillary glucose levels between 4.0 and 5.0 mmol/l the sensitivity for detecting GDM ranged between 87% and 47% and the specificity ranged between 51% and 96%. Fasting capillary glucose can be used as a screening test for GDM, but the appropriate cut-off value to use depends upon clinical practice.Paper II: In a population-based cohort study using data from the SMBR from between 1991 and 2003 (N = 1 260 297) maternal and neonatal outcomes were significantly worse in the group of women with GDM than in the background population. Between the study periods 1991–1997 and 1998–2003 there was no significant improvement in outcomes.Paper III: Maternal and neo-natal outcomes for GDM in Nordic versus non-Nordic women were analysed in a population-based cohort study using data from the SMBR from 1998–2007 (N = 8560). The prevalence of GDM varied by country of birth (0.7% in women from Sweden; 2.9% in women from North Africa). Non-Nordic women had less preeclampsia and hypertension and fewer LGA babies. LGA is highly dependent on maternal height and individual growth curves are needed to correctly estimate birth weights.Paper IV: A population-based case-control study using data from health registers in Sweden for 2642 women diagnosed with CVD and 13316 controls. The OR for GDM as an independent risk factor for cardiovascular disease was 1.5 (1.01–2.11). The combination of overweight and GDM identifies a group with particular risk, with an OR of 2.35 (1.38-3.99). No association was seen for GDM with CVD in normal weight women.