Association of altered serum acylcarnitine levels in early pregnancy and risk of gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a high-prevalence disease and diagnosed in middle pregnancy. Acylcarnitines are a series of fatty acid esters of carnitine and play important roles in fatty acid and carbohydrate metabolism. However, the role of acylcarnitine on the development of GDM remains unclear. This case-control study involving 214 study participants (107 GDM cases and 107 matched controls) was conducted in a cohort, in China, from 2013 to 2015. The levels of carnitine and 36 acylcarnitines in serum samples collected at the early stage of pregnancy were determined by using ultra-high performance liquid chromatography coupled with tandem mass spectrometry. The associations of the levels of the 37 targeted compounds with GDM risk were investigated by using binary conditional logistic regression models. Alterations in acylcarnitine levels were observed 9–17 weeks before GDM diagnosis. The increases in levels of propionyl-carnitine, malonyl-carnitine, isovaleryl-carnitine, palmitoyl-carnitine and linoleoyl-carnitine were associated with GDM risk with odds ratios (ORs) per standard deviation (SD) increment greater than 1 (p<0.05), after adjustment for potential confounding factors (pre-pregnancy body mass index and parity). On the contrary, the increases of decanoyl-carnitine, decenoyl-carnitine, tetradecenoyl-carnitine, tetradecandienoyl-carnitine levels were associated with the reduced risk for GDM (ORs per SD <1, p<0.05). To our knowledge, the present study is the largest case-control study to investigate the association between early-pregnancy acylcarnitine levels in serum and GDM risk. The findings add to the evidence for the association between acylcarnitine levels and GDM risk.