CORRELATIONS AMONG HUMAN BLOOD-LEVELS OF SPECIFIC PCB CONGENERS AND IMPLICATIONS FOR EPIDEMIOLOGIC STUDIES

Specific congeners of PCBs may differ with respect to their human heal th risks. For epidemiologic studies, however, measuring levels of spec ific congeners-as compared with estimating the concentration of total PCBs present, may be of limited value if levels of specific congeners are highly correlated. We examined the correlations among levels of sp ecific congeners in three groups: controls from a case-control study o f breast cancer in North Carolina and two groups from Wisconsin with e xposure to fish from contaminated waters. Levels of specific congener were, in general, highly correlated (Pearson r > 0.80). However, the l evel of congener 180, a heptachlorobiphenyl, tended to be less correla ted with levels of lower-chlorinated biphenyls. Among the implications of these findings are that measurement of a select group of congeners may yield essentially the same information as measurement of a large panel, and may be more cost efficient. (C) 1997 Wiley-Liss, Inc.