Abstract 2572: Vitamin D intake and lung cancer risk in the Women's Health Initiative (WHI).

Abstract

Abstract Background: Prior research suggests that vitamin D protects against lung cancer with evidence only among subgroups including women and non-smokers. We investigated whether vitamin D intake was associated with lung cancer and explored whether vitamin A intake modified the association. Methods: Data from 128,779 postmenopausal women including 1,771 incident lung cancers in the Women's Health Initiative, 1993-2010, were analyzed. Twelve percent of women received active intervention (1 g calcium+400 IU vitamin D3 daily) in the Calcium/Vitamin D Trial. Baseline total intake was assessed by a food frequency questionnaire and supplement bottle labels. Hazard ratios (HR) were estimated by Cox proportional hazard models. Results: No association was observed overall. Among never smokers, vitamin D intake was inversely associated with total lung cancer (HR=0.37, 95% confidence interval [CI]=0.18-0.77, ≥800 vs. <100 IU/d; P-trend=0.01). The Calcium/Vitamin D Trial active intervention was not associated with a lower lung cancer risk among women with vitamin A intake ≥1,000 μg/d Retinol Activity Equivalent (RAE), but among those with vitamin A intake <1,000 μg/d RAE (HR=0.69, 95% CI=0.50-0.96; P-interaction=0.09). Among current smokers with excess vitamin A intake (≥3,000 μg/d RAE), the intervention was associated with a higher lung cancer risk (HR=2.26, 95% CI=1.02-5.01), as no association was observed among current smokers with vitamin A intake <3,000 μg/d RAE (P-interaction=0.01). Conclusion: Vitamin D intake was associated with a lower lung cancer risk in never-smoking, postmenopausal women. Lower vitamin A intake may be important for a beneficial association of 1 g calcium+400 IU vitamin D3 supplementation with lung cancer. Citation Format: Ting-Yuan David Cheng, Andrea Z. LaCroix, Shirley A.A. Beresford, Gary E. Goodman, Mark D. Thornquist, Yingye Zheng, Rowan T. Chlebowski, Gloria Y.F. Ho, Marian L. Neuhouser. Vitamin D intake and lung cancer risk in the Women's Health Initiative (WHI). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2572. doi:10.1158/1538-7445.AM2013-2572