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

SIMPLE SUMMARY: Lung cancer is the second most common cancer and the leading cause of cancer death in the U.S. It is critical to identify the risk factors for lung cancer. However, previous results on the associations of dietary carotenoids and vitamin A intakes with lung cancer risk were inconclusive, and the study populations were mainly European descendants and Asians. This study aimed to prospectively investigate the associations among low-income African Americans and European Americans using resources from the Southern Community Cohort Study. Our findings suggested positive associations between dietary vitamin A intake and lung cancer risk among current smokers and racial-specific associations between dietary vitamin A intake and adenocarcinoma risk. Our study may contribute to understanding the role of nutrient intakes and lung cancer associations among the underrepresented study populations and improving the risk assessment of lung cancer risk. ABSTRACT: 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.