[Relation between waist circumference and risk of male lung cancer incidence: a prospective cohort study].

To investigate the association between waist circumference and risk of male lung cancer incidence. Since May 1, 2006, all the male employees including the retirees in Kailuan Group had been recruited into a Chinese Kailuan Male Cohort study. Information on anthropometries including body weight, height and waist circumference were collected at the baseline investigation, as well as information on newly-diagnosed lung cancer cases during the follow-up period. Waist circumference was grouped by quintiles of the population waist circumference distribution and categorized into the following five groups: <80, 80-, 85-, 90- and ≥95 cm, with the relevant normal group, the second quintile group (80-cm), serving as the referent category. Multivariable Cox proportional hazards regression models were used to evaluate the association between levels of waist circumference and risk of lung cancer. A total of 105 386 males were recruited in the study, with 739 651.13 person-years of follow-up and an average follow-up period of 7.00 years. By the end of 2014, a total of 707 lung cancer cases were identified in the cohort study. Compared with males having the 80-cm of waist circumference, the hazard ratio () and 95% confidence intervals () of lung cancer were 1.17(0.90-1.52), 0.96(0.74-1.23), 0.94(0.72-1.21) and 0.80(0.63-1.03) for the <80, 85-, 90- and ≥95 cm of waist circumference, after adjustment for potential confounding factors including age, education level, smoking status and pack-year amount, alcohol consumption, physical activities, environment for working place and the prevalence on diabetes. The inverse association existed in smokers (≥95 cm compared to 80-cm of waist circumference: =0.69, 95: 0.48-0.99) and alcohol drinkers (≥95 cm compared to 80-cm of waist circumference: =0.65, 95: 0.45-0.94) when analysis was conducted in subgroups stratified by smoking or alcohol drinking status. Waist circumference might be inversely associated with male lung cancer risk.