Mediating effects of body composition at the first trimester on the occurrence of GDM at the early stage of the third trimester during the advanced maternal age

Objective To retrospectively analyze the mediating effects of body composition during the first trimester on the occurrence of gestational diabetes mellitus (GDM) in early third trimester in advanced maternal age (AMA). Methods From December 2017 to May 2018, 1635 singleton pregnant women who underwent delivery in the Guiyang Maternal and Child Health Hospital were selected. The body composition data was measured by using the INBODY770 body composition instrument in the first trimester (mainly at a gestational age of 10–12 weeks). The blood glucose levels at fasting for one night and the cutoff values for them at 1 and 2 h after administration during the 75 g oral glucose tolerance test at gestational age of 24–28 weeks (the early stage of the 3rd trimester) were also collected. According to the Baron and Kenny’s criteria (the basic principle of interpreting the intermediary role), multivariate logistic regression was used to analyze the mediating effects of body composition (body fat percentage and protein percentage) between AMA and GDM occurrence. Results In total, 1635 subjects aged 30.93 ± 4.80 years were selected, and there were 376 women with AMA (23%). There were 983 pregnant women (39.88%) with a body fat percentage greater than 30% and 1331 (81.71%) pregnant women with a protein percentage less than 15%. The results showed significant differences in height, weight, lean body weight, body fat, body fat percentage, and GDM prevalence between AMA and low-age groups ( p < 0.05). After adjusting height, parity, and AMA, the body fat percentage showed association with GDM (odds ratio, OR 1.85 (1.38 ~ 2.48); confidence interval, CI 95%, p < 0.05). After adjusting height, parity, and body weight percentage, the AMA showed association with GDM (OR (CI95%) 2.38 (1.68 ~ 3.37)). Similarly, the protein percentage showed association with GDM (OR (CI 95%) 0.50 (0.31 ~ 0.81), p < 0.05). Conclusion These results confirmed the mediating effects of body fat percentage and protein percentage on AMA and the occurrence of GDM. Advanced age is directly associated with increased risk of GDM, which in turn increases with higher percentage of body fat and lower percentage of protein.