Abstract
BACKGROUND: Postprandial glucose (PPG) and insulin responses play a role in carcinogenesis. We evaluated the association between dietary glycemic index (GI) and glycemic load (GL), markers of carbohydrate intake and PPG, and lung cancer risk in non-Hispanic whites. METHODS: GL and GI were assessed among 1,905 newly diagnosed lung cancer cases recruited from the University of Texas MD Anderson Cancer Center (Houston, TX) and 2,413 healthy controls recruited at Kelsey-Seybold Clinics (Houston, TX). We assessed associations between quintiles of GI/GL and lung cancer risk and effect modification by various risk factors. ORs and 95% confidence intervals (CI) were estimated using multivariable logistic regression. RESULTS: We observed a significant association between GI [5th vs. 1st quintile (Q) OR = 1.49; 95% CI, 1.21-1.83; P(trend) <0.001] and lung cancer risk and GI(ac) (5th vs. 1st Q OR = 1.48; 95% CI, 1.20-1.81; P(trend) = 0.001) and lung cancer risk. We observed a more pronounced association between GI and lung cancer risk among never smokers (5th vs. 1st Q OR = 2.25; 95% CI, 1.42-3.57), squamous cell carcinomas (SCC; 5th vs. 1st Q OR = 1.92; 95% CI, 1.30-2.83), and those with less than 12 years of education (5th vs. 1st Q OR = 1.75; 95% CI, 1.19-2.58, P(interaction) = 0.02). CONCLUSION: This study suggests that dietary GI and other lung cancer risk factors may jointly and independently influence lung cancer etiology. IMPACT: Understanding the role of GI in lung cancer could inform prevention strategies and elucidate biologic pathways related to lung cancer risk.