# Evaluation of Plasticiser Levels, Phthalates and Bisphenols in Bahraini Subjects with and Without Type-2 Diabetes

## TL;DR

This study examines plasticiser exposure in Bahraini individuals with and without type-2 diabetes, finding differences in phthalate levels influenced by age and BMI.

## Contribution

The study is the first to evaluate plasticiser exposure in Bahrain and reveals altered exposure-response relationships in individuals with type-2 diabetes.

## Key findings

- Mono-n-butyl phthalate (MnBP) levels were higher in individuals with type-2 diabetes.
- Levels of MCPP, MECPP, MEP, and BPS were significantly lower in individuals with type-2 diabetes compared to controls.
- Age and BMI had reversed influences on plasticiser levels in individuals with type-2 diabetes compared to healthy controls.

## Abstract

Background: Plasticisers with endocrine-disrupting potential are ubiquitous and associate with obesity and type-2 diabetes (T2D), with higher levels reported in the Middle East. However, no data exist on plasticiser exposure in Bahrain where T2D affects 15% of the national population. Methods: An observational exploratory study in T2D (n = 60) and controls (n = 96), analysed for 24 h urinary plasticiser levels (liquid chromatography tandem mass spectrometry (LC-MS/MS)). Correlation and generalised linear model (GLM) analyses were employed to examine associations. Results: T2D were older (p < 0.001), had higher body mass index (BMI) (p < 0.001), body weight (p < 0.001) and glycosylated haemoglobin A1c (HbA1c) (p < 0.001). Correlation analysis revealed differences in inter-plasticiser, and plasticiser and biomarker relationships, with loss or reversal in T2D compared to controls. Mono-n-butyl phthalate (MnBP) levels were higher in T2D (p = 0.04); however, regression analysis revealed significant association with age. The GLM analyses demonstrated marked differences in the levels of mono(3-carboxypropyl) phthalate (MCPP), mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), monoethyl phthalate (MEP) and bisphenol S (BPS), with lower levels in T2D versus controls (B = −3.41, p = 0.01; B = −5.28, p < 0.001; B = −8.94, p < 0.001; B = −6.09, p = 0.006, respectively); however, these contrasts appeared to be substantially confounded by BMI and/or age. Positive influence of age and negative influence of BMI when observed across the full dataset were generally reversed in T2D. Levels were complementary to those previously reported for the Middle East. Conclusions: The study indicates the phthalate levels in Bahrain are elevated though complementary to studies of phthalates in the Middle East; within those levels, the study indicates differential exposure–response relationships with plasticisers, influenced by age and BMI, in those with T2D compared to healthy controls.