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.

Insecticide exposure and farm history in relation to risk of lymphomas and leukemias in the Women's Health Initiative observational study cohort

“…In a case-control study in New York state, women who worked for 10+ years on a farm where pesticides were used had 2.12 times the odds of NHL compared to women who never worked on a farm (95% CI: 1.21–3.71) [20]. In Iowa, women living on a farm had a more than 2-fold higher risk of acute myeloid leukemia (AML) compared to women living in a city of 10,000+ residents (95% CI: 1.25–3.99, 30 exposed cases) [28]. Due to small numbers, we did not report results for AML only.…”

Allergic Diseases and Risk of Hematopoietic Malignancies in a Cohort of Postmenopausal Women: A Report from the Iowa Women's Health Study

“…(38,41,42) Briefly, 98,030 women aged 55–69 years randomly identified through the 1985 Iowa driver’s license records were contacted via mail in 1986 and asked to participate in a study of women’s health. The 41,836 women who responded to the baseline questionnaire (42.7%) constituted the cohort.…”

“…Importantly, a sizable proportion of Iowa residents live in rural areas (39% in 1990(30)) or specifically on farms (9.2% versus 1.6% nationally in 1990(31)). Given the previously observed links between agricultural exposures and both allergies(32–37) and hematopoietic malignancies,(38–40) respectively, we examined possible differences in susceptibility for those with rural versus urban residences.…”

Personal samplers of bioavailable pesticides integrated with a hair follicle assay of DNA damage to assess environmental exposures and their associated risks in children

“…Pesticides, including the widely used organophosphate insecticides, induce DNA damage [9, 10], which is a common pathological characteristic of neurological disorders [11–13] and which increases cancer risk. Pesticide exposures are indeed associated with increased prevalence of multiple malignancies including lung [14], bladder [15, 16], non-Hodgkin lymphoma [17, 18], multiple myeloma [19] and acute myeloid leukemia [20] in adults. Although the effects of chronic pesticide exposure in children and adolescents remain poorly understood, increased childhood leukemia and brain tumors have been reported in rural areas or in association with parental and household pesticide exposures [21–24].…”