Urinary bisphenol A is associated with insulin resistance and obesity in reproductive-aged women

The prevalence of obesity has markedly increased and is closely related to insulin resistance. Although lifestyle and genetic predisposition are significant factors influencing the pathophysiology within the body, endocrine-disrupting chemicals (EDCs) are also important triggers of metabolic disturbance. We investigated the relationship between exposure to EDCs and insulin resistance and obesity in healthy, reproductive-aged women.

This cross-sectional analysis included 296 healthy, reproductive-aged women between 30 and 49 years. Metabolically healthy was defined as an absence of the components of metabolic syndrome. Urinary levels of bisphenol A (BPA), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono-n-butyl phthalate (MnBP) were measured by high-performance liquid chromatography and tandem mass spectroscopy (LC-MS). Homoeostatic model analysis of insulin resistance (HOMA-IR) was utilized as an index of insulin resistance.

Urinary BPA levels were positively correlated with BMI, waist circumference, fasting serum insulin and HOMA-IR. MEHHP, MEOHP and MnBP were not associated with any of the above parameters. In the multiple regression analysis, the BPA levels were significantly associated with BMI and waist circumference after adjusting for age, smoking and alcohol consumption status, triglycerides (TG), total cholesterol (TC) and high-density lipoprotein (HDL). Fasting insulin and HOMA-IR values were also significantly related to urinary BPA concentration after adjusting for confounding variables. Metabolically unhealthy women exhibited significantly higher levels of urinary BPA (P = 0·01) compared to metabolically healthy women.

Higher urinary BPA levels are associated with obesity, insulin resistance and metabolic disruption in Korean reproductive-aged women. BPA could play an important role in the pathogenesis of metabolic abnormalities. Further studies are required to elucidate the relationship between EDCs and metabolic disturbances in various age and sex groups.