RESUMO
INTRODUCTION: Wilms' tumor (WT) is the most frequent embryonic renal neoplasia in children. OBJECTIVE: This study was carried out to investigate risk factors in the development of WT. MATERIAL AND METHODS: A design of cases and controls, proactive, of incident cases, with four controls per case. The study population of cases were children of two oncologic reference Center of the Mexican Institute of Social Security (IMSS) in the Mexican Federal District during 5-year period. For the control group, children were frequency matched by age and sex at with cases from the same clinic. A questionnaire, previously validated, was applied to determine risk factors in both groups. RESULTS: During the period of study, 34 cases and 136 controls were revised. Significant risk factors were: antecedent of a relative with Down syndrome (OR = 7.6, 95%CI 1.4-51.1, p = 0.008), eczema (OR = 3.7, 95%Cl 1.1-12, p = 0.01); having been conceived in autumn (OR = 5.4, 95%CI 1.3-31.6, p = 0.007) or winter (OR = 4.9, 95%Cl 1.1-29.9, p = 0.01), and beet ingestion (OR = S. 7, 95%Cl 1.7-19.4, p = 0.0007). CONCLUSIONS: In this study, influence of prenatal factors are shown and we attempt to explain the etiology of WT, the important of beet ingestion, and conclusions suggest that that more epidemiologic studies are necessary to determine the chain of events that causes Wilms' tumor.