Mortality among “never smokers” living with smokers: two cohort studies, 1981-4 and 1996-9

Few studies have examined the association between passive smoking and all cause mortality; most of these have had limited study power.1–4 We present results from two population cohorts of adults who had never smoked (“never smokers”), followed for three year mortality according to household exposure to secondhand smoke. The two cohorts comprised all New Zealand adults aged 45-74 years who responded to the 1981 and 1996 censuses and who identified themselves as never smokers, lived in a private dwelling (that is, not a prison, hospital, or other institution), and had provided data on smoking status for all household members aged 15 and over (87.0% of never smokers in 1981 and 85.3% in 1996). Never smokers living in households with one or more current smokers were regarded as being exposed to secondhand smoke in the home; those living in households with no current smokers were regarded as not exposed. Cohort members …