Meta-analysis of Hodgkin's disease among farmers.

Abstract

This study examined the association between Hodgkin's disease and farming. A series of meta-analyses of peer-reviewed studies was performed, using 30 studies published between 1981 and 1998. Prior to the meta-analyses, all the studies were reviewed and evaluated for heterogeneity and publication bias. Combined relative risks (RR) were calculated using the random effect model. The combined RR was 1.25 [95% confidence interval (95% CI) 1.11-1.42] for all the studies, and 1.08 (95% CI 0.91-1.29) for the studies involving female farmers. Significant heterogeneity among the studies was detected, and a stratified analysis was carried out by study design, country of study, and time of publication. Significantly elevated RR values were obtained for the case-referent studies (odds ratio 1.53, 95% CI 1.18-1.98) and proportionate mortality studies (PMR)(PMR 1.18, 95% CI 1.02-1.36). A decrease in risk was eminent in the more recent studies. The findings suggest that male farmers have a slightly elevated risk of developing Hodgkin's disease. No specific etiologic exposure was identified, but exposures commonly experienced by farmers (infectious microorganisms, herbicides and insecticides) may contribute to the occurrence of the disease.