Abstract
Low biodegradability and high lipophilicity of p,p’-dichlorodiphenyldichloroethylene (DDE), a metabolite of the insecticide DDT, leads to transport with lipids and accumulation in adipose tissue. This persistence allows for DDE to effect adipose tissue and lipid metabolism. A few small human studies have shown an association between DDE and blood lipids, although with some inconsistent conclusions. The aim of this study was to investigate the association between DDE exposure and altered levels of circulating lipids in a large human cohort. To evaluate the associations between DDE and human lipid profiles, plasma was collected from a subset of elderly Swedes in the Prospective Investigation of the Vasculature of Uppsala Seniors (PIVUS) cohort who were free from lipid lowering medication (n = 571). DDE concentrations in plasma were measured using high-throughput solid phase extraction and gas chromatography-high resolution mass spectrometry. Lipidomic analysis of plasma was performed with nuclear magnetic resonance spectroscopy. Linear models of lipids and DDE were statistically adjusted for sex and body mass index. Detectable levels of DDE were found in the plasma samples of all subjects. With elevated DDE levels, the comprehensive lipoprotein profile showed an elevation in total concentration of all diameters of very low density lipoprotein (VLDL) (p<0.001), low density lipoprotein (LDL) (p<0.008), intermediate density lipoprotein (IDL) (p<0.02), and in small high density lipoprotein (HDL) (p<0.05). Triglycerides and DDE were associated to varying degrees in lipoproteins (IDL > VLDL > LDL > HDL) and within total serum (p<0.005). DDE levels were positively associated with cholesterol and cholesterol ester levels only in VLDL and LDL (p<0.05) and with apolipoprotein B (p<0.0009). The positive associations observed between each lipoprotein class and elevated DDE support previous data suggesting that DDE interacts with lipoproteins within plasma. We speculate that both physio-chemical and biological mechanisms may explain why DDE does not uniformly associate with lipids across lipoproteins.