Environmental Tobacco Smoke and Heart Disease

To the Editor. —Dr Steenland¹ estimates more than 35000 deaths from ischemic heart disease occur annually in the United States from exposure to environmental tobacco smoke (ETS), a number similar to previous estimates by Wells² and Glantz and Parmley.³ These estimates conflict with overviews of the evidence prepared under the auspices of a number of national authorities, none of which considered a causal relationship demonstrated.⁴ The estimates take the epidemiological evidence essentially at face value, making adjustments only for a limited number of sources of bias, and failing to reflect the fragility of the data.

Steenland does not even mention publication bias, although a number of prospective studies presented data on lung cancer but not on heart disease. Nor does he mention the general paucity of available data. Only three studies^5-7 with more than 120 cases have been published despite the relatively high incidence of