title: Farm residence and lymphohematopoietic cancers in the Iowa Women's Health Study.
abstract: BACKGROUND
  Cancer incidence in male farmers has been studied extensively; however, less is known about risk among women residing on farms or in agricultural areas, who may be exposed to pesticides by their proximity to crop fields. We extended a previous follow-up of the Iowa Women's Health Study cohort to examine farm residence and the incidence of lymphohematopoietic cancers. Further, we investigated crop acreage within 750 m of residences, which has been associated with higher herbicide levels in Iowa homes.
  
  
  METHODS
  We analyzed data for a cohort of 37,099 Iowa women aged 55-69 years who reported their residence location (farm, rural (not a farm), town size based on population) at enrollment in 1986. We identified incident lymphohematopoietic cancers (1986-2009) by linkage with the Iowa Cancer Registry. Using a geographic information system, we geocoded addresses and calculated acreage of pasture and row crops within 750 m of homes using the 1992 National Land Cover Database. Cox regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) in multivariate analyses of cancer risk in relation to both residence location and crop acreage.
  
  
  RESULTS
  As found in an earlier analysis of residence location, risk of acute myeloid leukemia (AML) was higher among women living on farms (HR=2.23, 95%CI: 1.25-3.99) or rural areas (but not on a farm) (HR=1.95, 95%CI: 0.89-4.29) compared with women living in towns of >10,000 population. We observed no association between farm or rural residence and non-Hodgkin lymphoma (NHL; overall or for major subtypes) or multiple myeloma. In analyses of crop acreage, we observed no association between pasture or row crop acreage within 750 m of homes and risk of leukemia overall or for the AML subtype. Chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) risk was nonsignificantly elevated among women with pasture acreage within 750 m of their home (HRs for increasing tertiles=1.8, 1.8 and 1.5) and with row crop acreage within 750 m (HRs for increasing tertiles of acreage=1.4, 1.5 and 1.6) compared to women with no pasture or row crop acreage, respectively.
  
  
  CONCLUSIONS
  Iowa women living on a farm or in a rural area were at increased risk of developing AML, which was not related to crop acreage near the home. Living near pasture or row crops may confer an increased risk of CLL/SLL regardless of residence location. Further investigation of specific farm-related exposures and these cancers among women living on farms and in agricultural areas is warranted.
authors.affiliation: Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA.
authors.forename: Rena R
authors.initials: RR
authors.lastname: Jones
authors.affiliation: Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA; Mid-Atlantic Permanente Research Institute, Kaiser Permanente, Rockville, MD, USA.
authors.forename: Chu-Ling
authors.initials: CL
authors.lastname: Yu
authors.affiliation: Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA; JRN-Environmental Health Sciences, Ltd. North Bethesda, Maryland, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Nuckols
authors.affiliation: Department of Health Sciences Research, Mayo Clinic, Rochester, MN, USA.
authors.forename: James R
authors.initials: JR
authors.lastname: Cerhan
authors.affiliation: Westat Inc., Rockville, MD, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Airola
authors.affiliation: Division of Epidemiology & Clinical Research, Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Ross
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health and Health Services, George Washington University, USA.
authors.forename: Kim
authors.initials: K
authors.lastname: Robien
authors.affiliation: Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA.
authors.forename: Mary H
authors.initials: MH
authors.lastname: Ward
mesh_terms: D000368:Aged; D000383:Agriculture; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007484:Iowa / Q000453:epidemiology; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000139:chemically induced / Q000453:epidemiology*; D008875:Middle Aged; D010575:Pesticides / Q000506:poisoning*; D017698:Postmenopause / Q000187:drug effects; D012111:Residence Characteristics
chemical_list: D010575:Pesticides
keywords: Farm residence; GIS; Iowa Women׳s Health Study; Land use; Pesticides