Estimated intake of vitamin D and its interaction with vitamin A on lung cancer risk among smokers.

Publication Type:

Journal Article

Source:

International journal of cancer. Journal international du cancer, Volume 135, Issue 9, p.2135-45 (2014)

Keywords:

2014, April 2014, Center-Authored Paper, Nutrition Assessment Core Facility, Public Health Sciences Division, Shared Resources

Abstract:

Data are very limited on vitamin D and lung cancer prevention in high-risk populations. The authors investigated whether estimated vitamin D intake was associated with lung cancer risk and whether effect modification by vitamin A existed among current/former heavy smokers and workers with occupational exposure to asbestos. A case-cohort study selected 749 incident lung cancers and 679 non-cases from the Carotene and Retinol Efficacy Trial (CARET), 1988-2005. The active intervention was supplementation of 30 mg β-carotene+25,000 IU retinyl palmitate/day. Baseline total intake including both diet (from food frequency questionnaire) and personal supplements (from brand names linked to the labeled potencies) was assessed. Hazard ratios (HR) were estimated by Cox proportional hazard models. No significant association of total vitamin D intake with lung cancer was observed overall. However, total vitamin D intake ≥600 versus <200 IU/d was associated with a lower risk of non-small cell lung cancer among former smokers (HR=0.36, 95% confidence interval [CI]=0.13-0.96). Total vitamin D intake ≥400 versus <400 IU/d was associated with a lower risk of total lung cancer among participants who received the CARET active intervention (HR=0.56, 95% CI=0.32-0.99) and among those who had total vitamin A intake ≥1,500 µg/d Retinol Activity Equivalent (RAE; HR=0.46, 95% CI=0.23-0.91). The beneficial associations were attenuated among those who did not receive the CARET active intervention or who had total vitamin A intake <1,500 µg/d RAE (P-interaction=0.02 for current smokers). Our observation suggests that vitamin A may assist vitamin D in preventing lung cancer among smokers. © 2014 Wiley Periodicals, Inc.