Campaigners and authorities including the TUC have attacked a report partly funded by the tobacco industry which concluded that passive smoking might not increase the risk of heart disease and lung cancer by as much as has been claimed. The study in the British Medical Journal said the link between these conditions and exposure to second-hand smoke could be much weaker than generally believed. Previous research has suggested that exposure to environmental tobacco smoke could increase the risk of heart disease by 30 per cent. The BMA criticised the study because it only re-analysed a small part of data from a study that was dropped by its original funders, the American Cancer Society.

JE Enstrom and GC Kabat. Environmental tobacco smoke and tobacco related mortality in a prospective study of Californians, 1960-98, British Medical Journal, volume 326, pages 1057-61, May 2003. EurekAlert, 15 May 2003. Risks 106.