title: Farm and animal exposures and pediatric brain tumors: results from the United States West Coast Childhood Brain Tumor Study.
abstract: Nineteen counties from San Francisco and Los Angeles, California and Seattle, Washington were the United States sites for a large population-based case-control study of childhood brain tumors (CBTs), sponsored by the National Cancer Institute. CBT patients who were < 20 years of age and were diagnosed between 1984 and 1991 were reported to each region's cancer registry. The 801 control subjects were obtained by random digit dial and were frequency-matched to the 540 CBT patients in San Francisco and Seattle (one patient to two controls) and in Los Angeles (one patient to one control). Data collected by in-person interview with subjects' mothers were analyzed to investigate an association between risk for CBTs and life on a farm, exposure to farm animals (dairy cattle, beef cattle, pigs, sheep/goats, poultry, and horses), and some cat and non-farm horse exposures. Elevated risks for CBTs were observed in association with mothers' exposure to pigs [odds ratio (OR) = 3.8, 95% confidence interval (CI) = 1.2-12] and horses (OR = 2.2, 95% CI = 1.0-4.8) on a farm during the index pregnancy. Children diagnosed with primitive neuroectodermal tumors showed elevated risks for CBTs with personal and maternal prenatal exposure to pigs (child, OR = 4.0, 95% CI = 1.2-13; mother, OR = 11.9, 95% CI = 2.8-51) and poultry (child, OR = 3.0, 95% CI = 1.1-8.0; mother, OR = 4.0, 95% CI = 1.2-14). No other animal exposures of children or mothers were found to be consistently related to CBTs. Children diagnosed with primitive neuroectodermal tumors who were on a farm for > 1 year and were first on a farm when they were < 6 months of age also had increased risk for CBTs (OR = 3.9, 95% CI = 1.2-13). A somewhat increased risk for CBTs was found for children of mothers who ever had worked on livestock farms compared with mothers who never had worked on a farm (OR = 7.4, 95% CI = 0.86-64, based on five case mothers and one control mother who worked on livestock farms during the 5 years preceding the birth of the index child). The associations are consistent with those of two previous studies in Norway (P. Kristensen et al., Int. J. Cancer, 65: 39-50, 1996) and the United States and Canada (G. R. Bunin et al., Cancer Epidemiol. Biomark. Prev., 3: 197-204, 1994) that investigated the role of farm-related exposures in the etiology of CBTs.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Medicine, University of California at San Francisco, 94109, USA.
authors.forename: E A
authors.initials: EA
authors.lastname: Holly
authors.forename: P M
authors.initials: PM
authors.lastname: Bracci
authors.forename: B A
authors.initials: BA
authors.lastname: Mueller
authors.forename: S
authors.initials: S
authors.lastname: Preston-Martin
mesh_terms: D000293:Adolescent; D000328:Adult; D000383:Agriculture; D000818:Animals; D000829:Animals, Domestic; D001253:Astrocytes / Q000473:pathology; D001932:Brain Neoplasms / Q000453:epidemiology / Q000209:etiology*; D002415:Cats; D002417:Cattle; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure; D005260:Female; D006736:Horses; D006801:Humans; D007223:Infant; D008297:Male; D018242:Neuroectodermal Tumors, Primitive / Q000209:etiology; D016273:Occupational Exposure; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D014481:United States / Q000453:epidemiology