The impact of low tar cigarettes.

It seemed like a change for the best at the time. The change involved a progressive decrease, from the 1960s onwards, in the tar yield from cigarettes. The tar yield was readily measured using smoking machines. A firm basis existed for anticipating that a reduced yield of tar from cigarettes would result in a reduced incidence of lung cancer in people smoking them. So health authorities, including Cancer Councils in Australia, monitored the tar yield of cigarettes on the local market. In 1976, Wynder and Hoffman recorded that the average tar content of cigarettes in the United States fell from 31 to 24 mg per cigarette during the period 1958–1969. However the prediction that smoking cigarettes with a reduced tar yield would result in a lower rate of lung cancer has not occurred. What went wrong? This article examines the development of ‘low tar cigarettes’, the physiology of nicotine dependence, the carcinogenic compounds contained in tobacco smoke and how these factors combine to ensure that smoking ‘low tar cigarettes’ does not result in a reduced risk of lung cancer.