[Association between dietary vitamin A intake and gestational diabetes mellitus in the first trimester]

Objective: To investigate the relationship between dietary vitamin A intake and its sources in the first trimester and gestational diabetes mellitus (GDM). Methods: A prospective study was conducted to select women at 6-14 weeks of gestation in an obstetric clinic of a maternal and child health care medical institution in Chengdu in 2017. The types and quantities of food during the first trimester were collected by 3-day 24-hour dietary recalls. Dietary vitamin A intake was calculated based on the Chinese Food Composition Table (2018), and it was divided into animal and plant vitamin A intakes according to its food sources. An oral glucose tolerance test was performed at 24-28 weeks of gestation to diagnose GDM according to the Chinese guidelines for diagnosis and treatment of gestational diabetes mellitus (2014). According to the estimated average requirement (EAR) and recommended nutrient intake (RNI), dietary vitamin A intake was divided into low-level group (RNI). Animal and plant vitamin A intakes were divided into four groups (Q1-Q4) according to the quartile method, respectively. The association between dietary vitamin A intake, its different sources of vitamin A intake and GDM in the first trimester was analyzed by log-binomial regression models. Results: A total of 1 298 valid samples were finally included. The average dietary vitamin A intake, animal and plant vitamin A intakes in the first trimester were 341.1 (227.8-501.0) μgRAE/d, 139.3 (69.6-195.3) μgRAE/d and 184.2 (99.4-301.1) μgRAE/d, respectively. After adjusting for confounding factors, log-binomial regression analysis showed that the risk of GDM in high-level group of dietary vitamin A intake was lower than that in low-level group [RR (95%CI):0.53 (0.36-0.80)]. Pregnant women in the highest quartile of animal vitamin A intake had a lower risk of GDM than those in the lowest quartile [RR (95%CI):0.66 (0.47-0.95)]. No relationship between plant vitamin A intake and GDM was found. Conclusion: Dietary vitamin A intake in the first trimester is associated with the occurrence of GDM, and higher intake than RNI may reduce the risk of GDM. Higher vitamin A intake from animal-derived food is associated with decreased risk of GDM.