Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25-29, 2009: Symposium Abstracts: Symposia Presentations
*National Cancer Institute, Bethesda, MD, United States; †University of California, Berkeley, CA, United States; ‡Northern California Cancer Center, Berkeley, CA, United States; §Children's Hospital of Central California, Madera, CA, United States; and ¶Battelle Memorial Institute, Columbus, OH, United States.
Abstracts published in Epidemiology have been reviewed by the organizations of Epidemiology. Affliate Societies at whose meetings the abstracts have been accepted for presentation. These abstracts have not undergone review by the Editorial Board of Epidemiology.
The etiologic role of persistent organochlorine chemicals in childhood cancer risk has not been evaluated in population-based studies. House dust is a reservoir for chemicals used in the home and nearby environment. Ingestion of house dust is an important route of chemical exposure for young children. We estimated the risk of childhood leukemia associated with persistent organochlorine chemicals using carpet dust as an exposure indicator.
We studied 184 acute lymphocytic leukemia (ALL) cases 0–7 years of age and 212 birth certificate controls from the Northern California Childhood Leukemia Study (2000–2006). Using a high volume surface sampler (HVS3) vacuum, we sampled carpets that were present in the home before the diagnosis/reference date. We measured concentrations (ng/g) of six polychlorinated biphenyl (PCB) congeners (105, 118, 138, 153, 170, 180) and the organochlorine pesticides chlordane, p,p'-DDT and its metabolite p,p'-DDE, methoxychlor, and pentachlorophenol. Odds ratios were calculated using unconditional logistic regression analysis adjusting for demographics, age of the home, sampling season (for organochlorine pesticides), and breastfeeding (PCBs).
Detection of any PCB congener in the dust conferred a two-fold increased risk of ALL (OR = 1.97, 95% Confidence Interval [CI] 1.22–3.17). Compared to those in the lowest quartile of total PCBs, the highest quartile was associated with about a three-fold risk (OR = 2.78, 95% CI 1.41–5.48; p trend = 0.02). We observed significant positive trends in risk associated with concentrations of the PCB congeners 118, 138, and 153 (P for trend = 0.02, 0.03, 0.02, respectively). The associations with PCBs were stronger among non-Hispanic Whites, despite a similar distribution of exposure among all ethnic/racial groups. We observed no significant association with concentrations of chlordane, p,p'-DDT, p,p'-DDE, methoxychlor, or pentachlorphenol.
Our findings suggest that PCBs, which are considered probable human carcinogens and cause perturbations of the immune system, may be a risk factor for childhood leukemia.