Epidemiology

Breast Cancer Research and Treatment

, Volume 136, Issue 1, pp 267-275

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Exposure to polychlorinated biphenyl (PCB) congeners measured shortly after giving birth and subsequent risk of maternal breast cancer before age 50

  • Barbara A. CohnAffiliated withChild Health and Development Studies, Public Health Institute Email author 
  • , Mary Beth TerryAffiliated withDepartment of Epidemiology, Mailman School of Public Health of Columbia UniversityHerbert Irving Comprehensive Cancer Center, Columbia University Medical Center
  • , Marj PlumbAffiliated withPlumbline Coaching and Consulting, Inc.
  • , Piera M. CirilloAffiliated withChild Health and Development Studies, Public Health Institute

Abstract

Discrete windows of susceptibility to toxicants have been identified for the breast, including in utero, puberty, pregnancy, and postpartum. We tested the hypothesis that polychlorinated biphenyls (PCBs) measured during the early postpartum predict increased risk of maternal breast cancer diagnosed before age 50. We analyzed archived early postpartum serum samples collected from 1959 to 1967, an average of 17 years before diagnosis (mean diagnosis age 43 years) for 16 PCB congeners in a nested case–control study in the Child Health and Development Studies cohort (N = 112 cases matched to controls on birth year). We used conditional logistic regression to adjust for lipids, race, year, lactation, and body mass. We observed strong breast cancer associations with three congeners. PCB 167 was associated with a lower risk (odds ratio (OR), 75th vs. 25th percentile = 0.2, 95 % confidence interval (95 % CI) 0.1, 0.8) as was PCB 187 (OR, 75th vs. 25th percentile = 0.4, 95 % CI 0.1, 1.1). In contrast, PCB 203 was associated with a sixfold increased risk (OR, 75th vs. 25th percentile = 6.3, 95 % CI 1.9, 21.7). The net association of PCB exposure, estimated by a post-hoc score, was nearly a threefold increase in risk (OR, 75th vs. 25th percentile = 2.8, 95 % CI 1.1, 7.1) among women with a higher proportion of PCB 203 in relation to the sum of PCBs 167 and 187. Postpartum PCB exposure likely also represents pregnancy exposure, and may predict increased risk for early breast cancer depending on the mixture that represents internal dose. It remains unclear whether individual differences in exposure, response to exposure, or both explain risk patterns observed.

Keywords

PCBs Polychlorinated biphenyls Breast cancer Pregnancy Postpartum Prospective Human