Associations of Dietary Intakes of Carotenoids and Vitamin A with Lung Cancer Risk in a Low-Income Population in the Southeastern United States.

Observational studies found inverse associations of dietary carotenoids and vitamin A intakes with lung cancer risk. However, interventional trials among high-risk individuals showed that β-carotene supplements increased lung cancer risk. Most of the previous studies were conducted among European descendants or Asians. We prospectively examined the associations of lung cancer risk with dietary intakes of carotenoids and vitamin A in the Southern Community Cohort Study, including 65,550 participants with 1204 incident lung cancer cases. Multivariate Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Lung cancer cases had lower energy-adjusted dietary intakes of all carotenoids and vitamin A than non-cases. However, dietary intakes of carotenoids and vitamin A were not associated with overall lung cancer risk. A significant positive association of dietary vitamin A intake with lung cancer risk was observed among current smokers (HR Q4 vs. Q1 = 1.23; 95% CI: 1.02-1.49; P trend = 0.01). In addition, vitamin A intake was associated with an increased risk of adenocarcinoma among African Americans (HR Q4 vs. Q1 = 1.55; 95%CI: 1.08-2.21; P trend = 0.03). Dietary lycopene intake was associated with an increased risk of lung cancer among former smokers (HR Q4 vs. Q1 = 1.50; 95% CI: 1.04-2.17; P trend = 0.03). There are positive associations of dietary β-cryptoxanthin intake with squamous carcinoma risk (HR Q4 vs. Q1 = 1.49; 95% CI: 1.03-2.15; P trend = 0.03). Further studies are warranted to confirm our findings.