Farm Characteristics, Allergy Symptoms, and Risk of Non-Hodgkin Lymphoid Neoplasms in the Agricultural Health Study

Abstract

Background Because of unique exposures, studies among farmers may yield insights into the relationship between allergies and non-Hodgkin lymphoid neoplasms (NHL). We evaluated farm characteristics, allergic symptoms and conditions, and risk of NHL including specific subtypes in the Agricultural Health Study, a prospective cohort of farmers and spouses from North Carolina and Iowa. Methods We identified 710 incident cases of NHL (including chronic lymphocytic leukemia and multiple myeloma) among 82,370 participants with baseline data on crop and animal exposures, including 454 cases among 52,850 participants with baseline data on recent allergy symptoms (rhinitis) and living on a farm during childhood. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using multivariable-adjusted proportional hazards models. Results We observed reduced risks of NHL among farmers and spouses with rhinitis at baseline (HR=0.63, 95% CI=0.51–0.79), related to growing soybeans (HR=0.80, 95% CI=0.67–0.96), and among farmers who handled stored grains or hay (HR=0.66, 95% CI=0.52–0.82). Growing up on a farm was associated with increased NHL risk (HR=1.51, 95% CI=1.15–1.98). Results did not differ significantly by NHL subtype. Conclusions Both the reduced risk of NHL among those with allergy symptoms and specific farm exposures in adulthood, and the increased risk among those who grew up on a farm suggest that the host immune response to agricultural allergens may influence NHL development. Impact This prospective study is, to our knowledge, the first to investigate the relationship between allergy symptoms and NHL risk in farmers; confirmation of these findings in other farming populations is warranted.

Central nervous system tumors and agricultural exposures in the prospective cohort AGRICAN

“…which showed a 30% significant excess of brain cancers in farming . As suggested for non‐Hodgkin lymphoid neoplasms, a possible explanation of the observed increased in the CNS tumor risk is the lower prevalence of allergy conditions in farmers, related to the higher frequency of early exposures during childhood to various allergens in agriculture . Indeed, history of allergic conditions has been associated with a reduced risk of CNS tumors in several studies .…”

Systematic review and meta-analysis of glyphosate exposure and risk of lymphohematopoietic cancers

“…If glyphosate use was more common in such subjects, then RR estimates would have been biased upward if a childhood farm environment was inversely associated with NHL risk [53] and biased downward if the association was positive. [54] …”

Early-life farm exposures and adult asthma and atopy in the Agricultural Lung Health Study

“…25,37 In 2 reports from the ECRHS, the farming environment in the first year of life and growing up on a farm were strongly associated with a reduced risk of adult atopy (OR, 0.47; 95% CI, 0.24–0.93 and OR, 0.68; 95% CI, 0.50–0.94, respectively). 10,11 Similarly, a Danish study of young adults (mean age, 19), a German study of adults ages 18 to 44 years, and a Finnish study of adults age 31 years all reported reduced risk of atopic sensitization associated with early-life farming exposures.…”