DIETARY FACTORS AND RISK OF LUNG-CANCER IN NEVER-SMOKERS

We studied dietary risk factors for lung cancer among never-smokers in a population-based case-control study in Stockholm, 1989-1995, Study subjects weve older than 30 years of age and had never smoked regularl y. A total of 124 cases (35 men, 89 women) and 235 controls (72 men, 1 63 women) participated. Exposure information was obtained at interview with study subjects. The never-smoking status was validated by interv iews with next-of-kin. A protective effect was suggested for vegetable s, mediated primarily by carrots (relative risk [RR], 0.7; 95% confide nce interval [CI], 0.4-1.3, and 0.6, 0.3-1.1 for intermediate and high consumption of carrots, respectively). Non-citrus fruits appeared to lower the risk as well, with RR 0.6, 95% CI 0.3-1.3 and 0.5, 0.3-1.0 f or intermediate and high consumption, respectively. A protective effec t with dose-response was also seen for intake of beta-carotene and tot al carotenoids. Increased risks were seen for cultured milk products i n both genders (RR 2.0, 95% CI 1.1-3.4 for intermediate and 1.6, 0.9-2 .9 for high consumption), but for milk only among male high consumers. Our results support evidence linking a diet rich in vegetables and no n-citrus fruit with decreased lung cancer risk and suggests that among vegetables, carrot consumption is the most important component or mar ker for this effect in Sweden. The results regarding milk products cou ld be consistent with dietary fat as a risk factor for lung cancer, al though a move comprehensive assessment of fat intake is necessary to e xplore this relation. (C) 1998 Wiley-Liss, Inc.