Gender-specific effects of dietary carotenoid intake on lung cancer risk

B64

Lung cancer is the leading cause of cancer deaths in the United States and worldwide. Smoking is a well-established risk factor. In contrast, intake of dietary carotenoids and lung cancer risk has been investigated with inconsistent findings; therefore further investigation is warranted. Using data from an ongoing case-control study of 1,088 newly diagnosed, histologically confirmed lung cancer cases atThe University of Texas M. D. Anderson Cancer Center in Houston,TX and 1,414 healthy controls who were matched on age, gender, ethnicity, and smoking status, we examined the associations between dietary carotenoid intake and lung cancer risk using multiple logistic regression analysis. All analyses were adjusted for covariates ( i.e., pack-years smoked, alcohol intake, total folate, BMI, family history of cancer, gender, and the other carotenoids examined). Five individual (i.e. α-carotene, β-carotene, β-cryptoxanthin, lutein+zeaxanthin, and lycopene) carotenoids plus total carotenoid intake, as well as retinol intake were examined. We also investigated whether the associations between carotenoid intake and lung cancer risk differed by demographic and lifestyle characteristics, such as BMI, the number of pack-years smoked, and vitamin-mineral supplement use. We found that the protective association for the carotenoids differed by gender: for men, protective trends (p < 0.05) against lung cancer were found with increased dietary intake of α-carotene, lutein+zeaxanthin, and lycopene, whereas protective trends were seen only with β-carotene in women. For example, the odds ratios (OR) and 95% confidence intervals (CI) of lung cancer for women by increasing quartiles of β-carotene intake were 1.0, 0.86 ( 0.52-1.41), 0.45 (0.23-0.88), 0.31 (0.12-0.76), (p trend = 0.005) and the ORs and 95% CI for lycopene intake in men were 1.0, 0.82 (0.57-1.17), 0.59 (0.40-0.86), 0.48 (0.33-0.72) (p trend < 0.0001). There were few notable differences based on the demographic and lifestyle characteristics; however in a limited sample of African Americans, there appeared to be greater protection against lung cancer with increasing intake of β-carotene. Overall, these results suggest that dietary intake of specific carotenoids may differentially protect men and women. Given the known limitations of case-control studies, these findings must be interpreted with caution, yet should be investigated further.