Exposure to pesticides and risk of childhood cancer: a meta-analysis of recent epidemiological studies

A meta-analysis of case-control and cohort studies was done to clarify possible relationships between pesticide exposure and childhood cancer. Two cohort and 38 case-control studies were selected for the first meta-anal. After evaluating homogeneity among studies using the Cochran Q test, a pooled meta-odds ratio (OR), stratified for each cancer site, was calculated. Then a list of variables believed to play an important role in explaining the relation between parental pesticide exposure to pesticide and childhood cancer was developed and series of meta-analyses were performed. In addition a distinct meta-analysis for 3 cohort studies using relative risk (RR) data was done. The meta-analyses of the 3 cohort studies did not display any positive links between parental pesticide exposure and childhood cancer incidence; however, a meta-analysis of 40 studies with OR values showed lymphoma and leukaemia risks increased significantly in exposed children when their mother was exposed in the prenatal period (OR) 1.53; 95% confidence interval [CI], 1.22-1.91 and OR) 1.48; 95% CI, 1.26-1.75). The brain cancer risk was correlated with paternal exposure before or after birth (OR) 1.49; 95% CI, 1.23-1.79 and OR) 1.66; 95% CI, 1.11-2.49). The OR for leukaemia and lymphoma were higher when mothers were exposed to pesticides (via household use or professional exposure). Brain cancer incidence was affected by father exposure (occupational or household or garden pesticide use). Despite some limitations, the incidence of childhood cancer appeared to be associated with parental exposure during the prenatal period.

Authors: Vinson Florence, Merhi Maysaloun, Baldi Isabelle, Raynal Helene, Gamet-Payrastre Laurence (INRA, TOXALIM, Toulouse, Fr.). ;Full Source: Occupational and Environmental Medicine 2011, 68(9), 694-702 (Eng) ;