Abstract

It seems clear that parental smoking is harmful, although the magnitude of its effect may be smaller than sometimes suggested. However, smoking and other behaviours detrimental to health must be seen within a social and historical context. Individuals are not 'free choosing actors' and their behaviour is determined, at least in part, by their social and environmental circumstances. Smoking might better be regarded as a 'proximal' cause. 'Proximal' causes such as infectious or toxic agents are themselves subject to 'causes of causes' which are the determinants of exposure to these agents. Smoking may act as the 'proximal' cause, directly harming the fetus, but is itself caused by factors in the social and environmental circumstances. The complexity of the relationship between social and environmental circumstances, health related behaviours, and adverse outcomes cannot be resolved by the search for single causative agents. As Rutter points out, in order to begin to understand causal complexity 'it is necessary to examine distal causal relationships in the form of chains and of linked sequences involving several different, relatively short-term effects or operations' (p 2). Health promotion programmes sensitive to social context avoid 'victim blaming' and acknowledge that it is not enough to exhort mothers to 'stop smoking before and during pregnancy because this will harm your baby' (p 99). Mothers know that smoking can harm themselves and their babies and the vast majority want to give up. Their choice is limited by their social circumstances, and failure to recognise this has ensured the failure of health promotion initiatives aimed at smoking reduction during pregnancy. There are limitations in the techniques available to control for confounding in multivariate analysis and results must be interpreted with caution. Misinterpretation can lead to overemphasis of the role of single factors, diverting attention from complex pathways. While health related behaviours may be a 'proximal' cause of ill health, there is a duty on researchers, health promoters, and health policy makers to take account of the complex causal pathways in which these 'proximal' causes lie.