Review : Parental Smoking and Risk of Childhood Cancer: A Review of the Evidence

Abstract

This paper reviews evidence relating parental smoking to risk of cancer in their offspring, based on English-language papers covering the period 1957- 1997. Forty-eight case-control and prospective studies provided suitable data. The studies mainly considered maternal smoking during pregnancy, but some studies provided data for maternal smoking before and after pregnancy or at conception, for paternal smoking at various times and/or for maternal expo sure to passive smoking. While some studies presented data for several tumour types, others considered one specific type only. Tables were constructed listing unadjusted and covariate-adjusted relative risk estimates for each exposure index and tumour site. A weak association between childhood cancer and maternal smoking prior to pregnancy was observed. The evidence for paternal smoking and for the various other exposure sources measured was slightly stronger, while that for maternal smoking during and after pregnancy was unconvincing. Only limited evidence of a dose response was found for any exposure index. Various limitations of the studies, including failure to control for confounding variables, mean that the quite weak associations observed between parental smoking and childhood cancer cannot be confidently inter preted as arising from a causal relationship.