Parental occupation and Ewing's sarcoma: pooled and meta-analysis.
Etiologic data on Ewing's sarcoma family of tumors (ESFT) are limited, with only 5 case-control studies reported. Interesting associations, particularly related to parental occupation, have been noted, but results are somewhat inconsistent. We conducted a pooled analysis of 3 case-control studies to assess the overall associations between parental occupation and ESFT. The pooled analysis provided data on parental occupational exposure on 199 cases of ESFT and 1,451 controls. The pooled odds ratio for the periconception and gestation periods were 2.3 (95% CI = 1.3-4.1) for children whose fathers had worked on farms and 3.9 (95% CI = 1.6-9.9) for those whose mothers had farmed. For the periconception and gestation periods, there was a 3.5-fold increased risk for those with both parents having farmed and a doubling of risk for those with at least one parent having farmed; pattern of increasing risk with increasing number of years of postnatal parental exposure to farms was seen. No other occupational group (or more narrowly defined occupations) had other than minor inconsistent associations with the occurrence of ESFT. In addition, we conducted a meta-analysis of farm occupation (a main risk factor) including all 4 case-control studies that collected required information to consider parental occupation. Results of the meta-analysis were consistent with those from the pooled analysis. This collaborative analysis of available individual data on parental occupation and ESFT in the offspring provides evidence supporting the hypothesis of an association between ESFT and parental occupation in farming.