Role of dietary patterns for dioxin and PCB exposure

Dietary patterns were related to intake and blood concentrations of polychlorinated dibenzo‐p‐dioxins and dibenzofurans (PCDD/PCDFs), dioxin‐like polychlorinated biphenyls (dl‐PCBs) and selected non‐dioxin‐like‐PCBs (ndl‐PCBs). Intake calculations were based on an extensive food frequency questionnaire and a congener‐specific database on concentrations in Norwegian foods. The study (2003) applied a two‐step inclusion strategy recruiting representative (n=73) and high consumers (n=111) of seafood and game. Estimated median intakes of sum PCDD/PCDFs and dl‐PCBs of the representative and high consumers were 0.78 and 1.25 pg toxic equivalents (TEQ)/kg bw/day, respectively. Estimated median intakes of ndl‐PCBs (sum chlorinated biphenyl (CB)‐28, 52, 101, 138, 153, 180) were 4.26 and 6.40 ng/kg bw/day. The median blood concentrations of PCDD/PCDFs/dl‐PCBs were 28.7 and 35.1 pg TEQ/g lipid, and ndl‐PCBs (sum of CB‐101, 138, 153 and 180) 252 and 299 ng/g lipid. The Spearman correlations between dietary intake and serum concentration were r=0.34 (p=0.017) for dl‐compounds and r=0.37 (p<0.001) for ndl‐PCBs. Oily fish was the major source of dl‐compounds and ndl‐PCBs in high and representative consumers. Four dietary patterns were identified by principal component analysis. Two were related to high intakes, one dominated by oily fish ((Ω‐3)), the other by fish liver and seagull eggs (“northern coastal”). Only the latter was closely associated with high blood concentrations of dioxins and PCBs.