Meta-analysis of leukemia and farming.

A series of meta-analyses of peer-reviewed studies of leukemia and farming were performed and examined in the context of what is currently known about risk factors for leukemia. The analyses yielded inconsistent results; however, the preponderance of positive studies and lack of apparent publication bias suggests a weak association between farming and the disease. Reported excesses of all major subtypes of leukemia in farmers suggest that the association between farming and disease is due to a variety of exposures, which result in an overall excess of leukemia. Reported associations with specific subtypes of the disease are based on low numbers of cases and inconsistent due to the lack of exposures to strong risk factors universally experienced by farmers.