Passive smoking in relation to lung cancer incidence and histologic types in Norwegian adults: the HUNT study

Passive smoking has been proposed as a risk factor for lung cancer. The increased risks for lung cancer overall and different histologic types in relation to passive smoking were demonstrated in two meta-analytical studies [1, 2], in which the included studies were mostly case–control designs, which are subject to recall bias. To date, there have been a limited number of prospective studies on passive smoking in relation to lung cancer incidence, most of which included only never-smoking women [3–5]. There is also a lack of longitudinal investigations concerning the influence of passive smoking on different histologic types of lung cancer. We aimed to evaluate the influences of passive smoking during childhood and adulthood on the development of lung cancer and histologic types in a long-term follow-up cohort, and to assess possible sex-related differences in the association.