C-reactive protein and tumor necrosis factor-α in gestational hyperglycemia

Objectives and study design: Increasing evidences support an inflammatory origin for gestational hyperglycemia. This paper aims at investigating, cross-sectionally and prospectively, the relationships between tumor necrosis factor-alpha (TNF-alpha) and C-reactive protein (CRP) levels in normoglycemic and hyperglycemic pregnancies of women with and without conventional risk factors for gestational diabetes (GDM). Results: Both at simple and multiple correlations TNF-alpha levels are associated to fasting insulin, homeostasis model assessment-insulin resistance (HOMA-IR) values and gestational hyperglycemia, while high sensitivity CRP (hsCRP) levels to body mass index (BMI). Furthermore, the TNF-alpha levels of the second trimester and their increments in the third trimester are significant predictors of insulin levels measured at 32-36 weeks in the subgroup of hyperglycemic women with <= 35 yr, BMI <25 kg/m(2) and the absence of a first-degree relative with Type 2 diabetes (respectively, beta=1.1; 95%Cl 0.66-1.48; p=0.002 and beta=11.0; 95%Cl 0.36-1.66; p=0.02), in a multiple regression model, after multiple adjustments. In a second cohort of women at low risk for GDM (<25 yr, BMI <25 kg/m(2) and absence of a first-degree relative with Type 2 diabetes), 24-28 weeks TNF-alpha levels are highly associated with corresponding insulin and HOMA values in the same model (respectively, beta=0.27; 95%Cl 0.11-0.43; p=0.001 and beta=0.30; 95%Cl 0.14-0.46; p<0.001). Conclusions: the data support the developing hypothesis that low-grade systemic inflammation is associated to GDM, in particular for pregnant women without conventional risk factors for gestational hyperglycemia, whose insulin resistance seems less explainable.