Aim: Human exposure to organic pollutants (some of them also called endocrine disruptors) can be associated with adverse metabolic health outcomes including type 2 diabetes. The goal of this study was to compare the urine levels of bisphenol A and phthalate metabolites in subgroups of patients with metabolic syndrome composed of patients with and without three important components of metabolic syndrome (hypertension, dyslipidemia and diabetes).
Methods: We have investigated 24 hr urine samples of 168 patients with metabolic syndrome from the Metabolic Outpatient Department of General University Hospital in Prague. Using standard metabolic syndrome criteria, we classified patients as dyslipidemic (n=87), hypertensive (n=96), and type 2 diabetic (n=58). Bisphenol A and 15 metabolites of phthalates were evaluated in relation to creatinine excretion. Samples were analysed with enzymatic cleavage of glucuronide using ultra-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry in one laboratory with external quality control.
Results: Four metabolites, mono-n-butyl phthalate, mono-(2-ethyl-5-hydroxyhexyl) phthalate, mono-(2-ethyl-5-oxohexyl) phthalate, and mono-(2-ethyl-5-carboxypentyl) phthalate showed significantly higher levels in diabetic compared to non-diabetic patients (p<0.001, p=0.002, p=0.002, and p=0.005, respectively). The differences remained significant after adjustment to hypertension, dyslipidemia, age, and BMI. No difference was found between either the hypertensive and non-hypertensive or dyslipidemic and non-dyslipidemic patients. There was no significant relation of bisphenol A level to diabetes, hypertension, dyslipidemia, age, and BMI.
Conclusions: Urine levels of four phthalate metabolites were significantly higher in type 2 diabetics independently on specified predictors. Phthalate levels can be in relation to beta cell dysfunction in type 2 diabetic patients but this study is not able to show if the relation is causal.
Keywords: bisphenol A; endocrine disruptors; metabolic syndrome; obesity; organic pollutants; phthalates; type 2 diabetes.
Copyright© by the National Institute of Public Health, Prague 2016