Association between early pregnancy vitamin D status and changes in serum lipid profiles throughout pregnancy.

Objective: To evaluate the associations between first trimester 25-hydroxyvitamin D [25(OH)D] status and changes in high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), total cholesterol (TC), triglyceride (TG) concentrations, TG/HDL-c, and TC/HDL-c ratios throughout pregnancy. We hypothesized that first trimester 25(OH)D inadequacy is associated with lower concentrations of HDL-c and higher LDL-c, TC, TG, TG/HDL-c, and TC/HDL-c ratios throughout pregnancy.

Methods: A prospective cohort study with 3 visits at 5-13 (baseline), 20-26, and 30-36 gestational weeks, recruited 194 pregnant women attending a public health care center in Rio de Janeiro, Brazil. Plasma 25(OH)D concentrations were measured in the first trimester using liquid chromatography-tandem mass spectrometry. 25(OH)D concentrations were classified as adequate (≥75nmol/L) or inadequate (<75nmol/L). Serum TC, HDL-c, and TG concentrations were measured enzymatically. Crude and adjusted longitudinal linear mixed-effects models were employed to evaluate the association between the first trimester 25(OH)D status and changes in serum lipid concentrations throughout pregnancy. Confounders adjusted for in the multiple analysis were age, homeostatic model assessment (HOMA), early pregnancy BMI, leisure time physical activity before pregnancy, energy intake, and gestational age.

Results: At baseline, 69% of the women had inadequate concentrations of 25(OH)D. Women with 25(OH)D inadequacy had higher mean LDL-c than those with adequate concentrations (91.3 vs. 97.5mg/dL; P=0.064) at baseline. TC, HDL-c, LDL-c TG, TG/HDL-c ratios, and TC/HDL-c ratios, increased throughout pregnancy independently of 25(OH)D concentrations (ANOVA for repeated measures P<0.001). The adjusted models showed direct associations between the first trimester 25(OH)D status and changes in TC (β=9.53; 95%CI=1.12-17.94), LDL-c (β=9.99; 95% CI=3.62-16.36) concentrations, and TC/HDL-c ratios (β=0.16; 95% CI=0.01-0.31) throughout pregnancy.

Conclusions: Inadequate plasma 25(OH)D concentrations during early pregnancy were associated with more pronounced changes of TC, LDL-c concentrations, and TC/HDL-c ratios throughout pregnancy. Changes in these cardiovascular markers suggest the importance of ensuring adequate vitamin D status at the beginning of pregnancy.