Causal association between physical activity and sedentary behavior and gestational diabetes mellitus: A Mendelian randomization analysis

Abstract

Abstract Introduction Evidence of an association between physical activity (PA), sedentary behavior (SB) and gestational diabetes mellitus (GDM) remains controversial in observational studies, this study aimed to explore the causal association between PA, SB and GDM. MethodsOur study performed Mendelian randomization (MR) analysis to explore the effects of three types of PA (moderate physical activity (MPA), moderate to vigorous physical activity (MVPA), accelerometer-based physical activity (ABPA)), three types of SB (television watching (TV), leisure computer use (PC), driving (DR)) on GDM and the mediating effect of body mass index (BMI). The inverse variance weighted method was used for the major analysis. ResultsIn univariate MR analysis, we found that genetically predicted TV and PC among SB were associated with GDM (OR = 1.61, P = 0.001; OR = 0.71, P = 0.037), whereas, DR was not (OR = 1.68, P = 0.623). However, no association was found between physical activity and GDM: MPA (OR = 0.40, P= 0.273), MVPA (OR = 0.96, P = 0.861), and ABPA (OR = 0.99, P = 0.838). Multivariate MR analysis found that the causal effect of a 1 SD (1.5h) independently increase in the duration of TV was a 64% increase in the odds of GDM (OR = 1.64, P = 0.008) and that BMI was a mediating factor with a 62% mediating effect. ConclusionsThis study demonstrated an independently causal association between TV and GDM, which is mediated by BMI, providing evidence for reducing the risk of GDM during pregnancy by reducing television watching time.