Meta-analyses of brain cancer and farming.
BACKGROUND
A series of meta-analyses of peer-reviewed studies of brain cancer and farming were performed, using 33 studies published between 1981 and 1996.


METHODS
Before the meta-analyses, all studies were reviewed and evaluated for heterogeneity and publication bias. A random-effect model was used to estimate the combined relative risk.


RESULTS
A meta-analysis including all the studies yielded an estimator of relative risk equal to 1.30, with a 95% confidence interval (95% CI) of 1.09, 1.56. The estimator of relative risk obtained from a meta-analysis restricted to female farmers was 1.04 (95% CI = 0.84, 1.29). A third meta-analysis restricted to studies of farmers residing in the central United States resulted in an estimator of relative risk equal 1.25 (95% CI = 1.09, 1.44). These findings were not influenced by either a publication bias or a specific study design.


CONCLUSIONS
The consistent significant positive findings suggests that there is a weak association between brain cancer and farming. Exposures commonly experienced by farmers including infectious microorganisms and pesticides may contribute to the increased risk of brain cancer.
Medical College of Ohio, Toledo 43699-0008, USA. skhuder@vortex.mco.edu
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D000382:Agricultural Workers' Diseases / Q000453:epidemiology*; D001932:Brain Neoplasms / Q000453:epidemiology*; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D008297:Male; D016273:Occupational Exposure; D018570:Risk Assessment