Exposure to phenols mixture, oxidative stress, and fasting blood glucose: Association and potential mediation analyses

Abstract

Phenols exposure may affect glucose metabolism and increase the risk of type 2 diabetes (T2D). However, the underlying biological mechanisms were poorly understood. In this longitudinal panel study of 122 Chinese adults with three repeated measurements, we aimed to evaluate the associations of multiple phenols exposure with fasting blood glucose (FBG), odds of impaired fasting glucose (IFG) and T2D, and further assess the mediating role of oxidative stress in the above associations. FBG and urinary concentrations of 6 phenols and 3 oxidative stress biomarkers were repeatedly measured for each participant. Linear mixed-effect (LME) models, generalized estimating equations (GEEs), quantile g-computation models, and structural equation models (SEM) were employed to estimate the associations. We observed that urinary methyl paraben (MeP), ethyl paraben (EtP), and propyl paraben (PrP) at multiple lag days were independently associated with increased FBG (all P-FDR <0.05). Exposure to phenols mixture at lag 0 day was positively correlated with FBG, and urinary PrP was the predominant contributor. Meanwhile, exposure to phenols mixture at lag 1 day or at lag 3 day was marginally linked to increased FBG. No significant relationships of phenols exposure at different lag days with risk of IFG and T2D were observed. In addition, we found that 8-hydroxy-deoxyguanosine (8-OHdG) mediated 35.7 % of the association of urinary phenols mixture at lag 1 day with FBG. Our study revealed that phenols exposure, either separately or as a mixture, was related to increased FBG, and oxidative stress is a potential mediating mechanism.