Evaluation of serum lipid concentrations among U.S. workers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin.
In an effort to clarify the effects of exposure to 2,3,7,8- tetrachlorodibenzo-p-dioxin (1746016) (TCDD) on lipid metabolism in humans a cross sectional medical study was conducted. Blood cholesterol and triglyceride levels were measured in 281 workers who had been exposed to TCDD more than 15 years earlier during work in the production of 2,4,5-trichlorophenol or its derivatives, and in unexposed referents. Exposed workers had a median whole weight serum TCDD concentration of 406.6 femtograms/gram. This was significantly increased compared with referents. Median lipid adjusted serum TCDD levels were 68 picograms/gram lipid for exposed workers and 6 picograms/gram lipid for referents. No significant differences between the groups were identified for mean levels of total serum cholesterol, triglycerides, high density lipoprotein cholesterol (HDL), or total cholesterol/HDL ratio. Associations between serum TCDD levels and risk for abnormal HDL levels approached statistical significance in logistic regression analysis. A small, but significant, association between triglyceride level and serum TCDD level was seen with linear regression analysis. Triglyceride level increased about 0.4 millimole/liter over the range of observed TCDD values; whereas cigarette smoking, race, gender, body weight index, and the use of beta blockers were found to have a much greater influence on triglyceride levels. Increased risks for abnormal HDL and elevated triglyceride levels were seen for workers in the quartile with the highest serum TCDD levels. A significant trend was also identified for mean triglyceride level and TCDD quartiles. The authors conclude that high serum TCDD levels appear to affect lipid metabolism; however, this effect was small compared to the contribution of other factors.