Pre-pregnancy inflammatory and insulinemic dietary patterns and risk of gestational diabetes mellitus: a prospective cohort study of 14,674 women

Abstract

Backgroud: Gestational diabetes mellitus (GDM) is associated with various short-term and long-term adverse health outcomes for both mothers and offspring. It is critical to identify modifiable factors that may inform the prevention of GDM. We, therefore, examined whether pre-pregnancy pro-inflammatory and hyperinsulinemic dietary patterns are associated with increased risk of GDM. Methods: We included 14,674 women in the Nurses’ Health Study II who reported at least one singleton pregnancy between 1991 and 2001. We derived pre-pregnancy dietary pattern scores for empirical dietary inflammatory pattern (EDIP) and empirical dietary index for hyperinsulinemia (EDIH) from validated food frequency questionnaires collected before pregnancy. Incident first-time GDM was ascertained from self-report of a physician diagnosis with high validity. We used log-binomial models with generalized estimating equations to estimate the relative risks (RRs) and 95% confidence intervals (CIs) for the associations of pre-pregnancy EDIP and EDIH scores with GDM risk, adjusting for pre-pregnancy body mass index and other potential confounders. Results: Participants reported 20,337 pregnancies over 10 years of follow-up, with 831 complicated by GDM. Women with higher pre-pregnancy EDIP and EDIH scores had a greater risk of GDM: adjusted RRs (95% CIs) for EDIP increasing quintiles were 1.00 (reference), 1.22 (0.97, 1.53), 1.19 (0.94, 1.49), 1.40 (1.13, 1.75), and 1.41 (1.13, 1.75); for EDIH were 1.00, 1.19 (0.94, 1.52), 1.21 (0.95, 1.54), 1.29 (1.02, 1.64), and 1.58 (1.26, 1.98) (both P-trend: <0.001). The observed associations were generally consistent across stratum of major risk factors of GDM such as pre-pregnancy overweight or obesity status, family history of diabetes, and genetic susceptibility of GDM. Conclusions: In a large US cohort of predominantly White women, higher intake of pro-inflammatory and hyperinsulinemic diets was associated with increased risk of GDM. Further studies are warranted to confirm our findings, to provide evidence promoting anti-inflammatory and anti-hyperinsulinemic diets as a preventive measure for gestational diabetes in women planning pregnancy.