The University of Michigan Dioxin Exposure Study: Predictors of Human Serum Dioxin Concentrations in Midland and Saginaw, Michigan

Abstract

BackgroundWe conducted a population-based human exposure study in response to concerns among the population of Midland and Saginaw counties, Michigan, that discharges by the Dow Chemical Company of dioxin-like compounds into the nearby river and air had led to an increase in residents’ body burdens of polychlorinated dibenzofurans (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs), here collectively referred to as “dioxins.”ObjectivesWe sought to identify factors that explained variation in serum dioxin concentrations among the residents of Midland and Saginaw counties. Exposures to dioxins in soil, river sediments, household dust, historic emissions, and contaminated fish and game were of primary interest.MethodsWe studied 946 people in four populations in the contaminated area and in a referent population, by interview and by collection of serum, household dust, and residential soil. Linear regression was used to identify factors associated with serum dioxins.ResultsDemographic factors explained a large proportion of variation in serum dioxin concentrations. Historic exposures before 1980, including living in the Midland/Saginaw area, hunting and fishing in the contaminated areas, and working at Dow, contributed to serum dioxin levels. Exposures since 1980 in Midland and Saginaw counties contributed little to serum dioxins.ConclusionsThis study provides valuable insights into the relationships between serum dioxins and environmental factors, age, sex, body mass index, smoking, and breast-feeding. These factors together explain a substantial proportion of the variation in serum dioxin concentrations in the general population. Historic exposures to environmental contamination appeared to be of greater importance than recent exposures for dioxins.

Concentrations of persistent organic pollutants in California women's serum and residential dust

“…Serum lipid content and age were both positively related to serum concentrations of PCBs and OC pesticides, as has been noted in previous studies (Agudo, et al 2009; Bachelet, et al 2011; Garabrant, et al 2009; Glynn, et al 2007; Hardell, et al 2010; Ibarluzea, et al 2011; Laden, et al 1999; McGraw and Waller 2009a; Moysich, et al 2002; Schade and Heinzow 1998; Weiss, et al 2006; Wolff, et al 2005). In multivariable models, cumulative lactation time was associated with lower levels of several major legacy POPs, consistent with the hypothesis that mothers excrete POPs during lactation (Hardell, et al 2010; Ibarluzea, et al 2011; Laden, et al 1999; Moysich, et al 2002; Schade and Heinzow 1998; Wolff, et al 2005).…”

Sex, BMI and age in addition to dietary intakes influence blood concentrations and congener profiles of dioxins and PCBs

“…The higher concentration of CB-126 explains how total TEQ can be similar in blood from men and women when the dietary intake of total TEQ in women is lower. In contrast to our finding, the prediction model for CB-126 in the University of Michigan Dioxin Exposure Study did not show any association with female sex, but in agreement with our observations, significant association between total TEQ and increasing age and BMI was seen [24].…”

Estimation of Background Serum 2,3,7,8-TCDD Concentrations By Using Quantile Regression in the UMDES and NHANES Populations

“…Other covariates potentially associated with serum TCDD concentration were body mass index (BMI), recent BMI change, cigarette smoking, income, education, and breastfeeding history among women. 12 All of these covariates had less than 7.5% of data missing in both samples. They were imputed separately by using a sequential regression imputation method in both samples before the combination.…”