Original Article

Journal of Exposure Science and Environmental Epidemiology (2013) 23, 363–370; doi:10.1038/jes.2012.115; published online 16 January 2013

Exposure to herbicides in house dust and risk of childhood acute lymphoblastic leukemia

Catherine Metayer1, Joanne S Colt2, Patricia A Buffler1, Helen D Reed3, Steve Selvin1, Vonda Crouse4 and Mary H Ward2

  1. 1School of Public Health, University of California, Berkeley, California, USA
  2. 2Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, Department of Health and Human Services, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
  3. 3Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, Department of Health and Human Services, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
  4. 4Department of Pediatric Oncology, Children’s Hospital Central California, Madera, California, USA

Correspondence: Dr. Catherine Metayer, School of Public Health, University of California, Berkeley, 1995 University Avenue, Suite 460, Berkeley, CA 94704-7392, USA. Tel.: +1 510 643 1156. Fax: +1 510 642 9319. E-mail: cmetayer@berkeley.edu

Received 7 May 2012; Revised 12 October 2012; Accepted 14 November 2012
Advance online publication 16 January 2013

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Abstract

We examine the association between exposure to herbicides and childhood acute lymphoblastic leukemia (ALL). Dust samples were collected from homes of 269 ALL cases and 333 healthy controls (<8 years of age at diagnosis/reference date and residing in same home since diagnosis/reference date) in California, using a high-volume surface sampler or household vacuum bags. Amounts of agricultural or professional herbicides (alachlor, metolachlor, bromoxynil, bromoxynil octanoate, pebulate, butylate, prometryn, simazine, ethalfluralin, and pendimethalin) and residential herbicides (cyanazine, trifluralin, 2-methyl-4-chlorophenoxyacetic acid (MCPA), mecoprop, 2,4-dichlorophenoxyacetic acid (2,4-D), chlorthal, and dicamba) were measured. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by logistic regression. Models included the herbicide of interest, age, sex, race/ethnicity, household income, year and season of dust sampling, neighborhood type, and residence type. The risk of childhood ALL was associated with dust levels of chlorthal; compared to homes with no detections, ORs for the first, second, and third tertiles were 1.49 (95% CI: 0.82–2.72), 1.49 (95% CI: 0.83–2.67), and 1.57 (95% CI: 0.90–2.73), respectively (P-value for linear trend=0.05). The magnitude of this association appeared to be higher in the presence of alachlor. No other herbicides were identified as risk factors of childhood ALL. The data suggest that home dust levels of chlorthal, and possibly alachlor, are associated with increased risks of childhood ALL.

Keywords:

childhood leukemia; herbicides; pesticides; dust

Abbreviations:

AHS, Agricultural Health Study; ALL, acute lymphoblastic leukemia; CI, confidence interval; 2,4-D, 2,4-dichlorophenoxyacetic acid; DCPA, dimethyl tetrachloroterephthalate; IARC, International Agency for Research on Cancer; MCPA, 2-methyl-4-chlorophenoxyacetic acid; MCPP, methylchlorophenoxypropionic acid; NCCLS, Northern California Childhood Leukemia Study; OR, odds ratio; USEPA, United States Environmental Protection Agency; 2,3,7,8-TCDD, 2,3,7,8-tetrachlorodibenzo-p-dioxin