Data Sheet 1_Associations between serum persistent organic pollutants and type 2 diabetes in a multipollutant analysis using repeated measurements in the Tromsø Study.docx

We investigated associations between a mixture of POPs measured repeatedly before type 2 diabetes mellitus diagnosis (T2DM).</p>Material and methods<p>In a longitudinal nested case-control study within the Tromsø Study, serum concentrations of 19 chlorinated POPs were measured at three pre-diagnostic timepoints: T1 (1986/87; 15–21 years before diagnosis, n = 259), T2 (1994/95; 7–13 years before diagnosis, n = 257), and T3 (2001; 0–6 years before diagnosis, n = 260).

Lipid-adjusted POP concentrations were analyzed using positive-direction weighted quantile sum (WQS) logistic regression. Single-pollutant analyses were conducted for comparison.</p>Results<p>The POP mixture was positively associated with subsequent T2DM at T2 [odds ratio (OR) 2.14, 95% confidence interval (CI) 1.34–3.42] and T3 (OR 1.78, 95% CI 1.19–2.66), whereas no association was detected at T1. Cis-heptachlor epoxide and p,p'-DDT received the largest weights at T2.