Meta-analyses of brain cancer and farming

Am J Ind Med. 1998 Sep;34(3):252-60. doi: 10.1002/(sici)1097-0274(199809)34:3<252::aid-ajim7>;2-x.


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.

Conclusion: 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.

Publication types

  • Meta-Analysis

MeSH terms

  • Agricultural Workers' Diseases / epidemiology*
  • Brain Neoplasms / epidemiology*
  • Confidence Intervals
  • Female
  • Humans
  • Male
  • Occupational Exposure
  • Risk Assessment