TY - JOUR
T1 - Carotenoids and the risk of developing lung cancer
T2 - A systematic review
AU - Gallicchio, Lisa
AU - Boyd, Kristina
AU - Matanoski, Genevieve
AU - Tao, Xuguang
AU - Chen, Liwei
AU - Lam, Tram K.
AU - Shiels, Meredith
AU - Hammond, Edward
AU - Robinson, Karen A.
AU - Caulfield, Laura E.
AU - Herman, James G.
AU - Guallar, Eliseo
AU - Alberg, Anthony J.
PY - 2008/8/1
Y1 - 2008/8/1
N2 - Background: Carotenoids are thought to have anti-cancer properties, but findings from population-based research have been inconsistent. Objective: We aimed to conduct a systematic review of the associations between carotenoids and lung cancer. Design: We searched electronic databases for articles published through September 2007. Six randomized clinical trials examining the efficacy of β-carotene supplements and 25 prospective observational studies assessing the associations between carotenoids and lung cancer were analyzed by using random-effects meta-analysis. Results: The pooled relative risk (RR) for the studies comparing β-carotene supplements with placebo was 1.10 (95% confidence limits: 0.89, 1.36; P = 0.39). Among the observational studies that adjusted for smoking, the pooled RRs comparing highest and lowest categories of total carotenoid intake and of total carotenoid serum concentrations were 0.79 (0.71, 0.87; P < 0.001) and 0.70 (0.44, 1.11; P = 0.14), respectively. For β-carotene, highest compared with lowest pooled RRs were 0.92 (0.83, 1.01; P = 0.09) for dietary intake and 0.84 (0.66, 1.07; P = 0.15) for serum concentrations. For other carotenoids, the RRs comparing highest and lowest categories of intake ranged from 0.80 for β-cryptoxanthin to 0.89 for α-carotene and lutein-zeaxanthin; for serum concentrations, the RRs ranged from 0.71 for lycopene to 0.95 for lutein-zeaxanthin. Conclusions: β-Carotene supplementation is not associated with a decrease in the risk of developing lung cancer. Findings from prospective cohort studies suggest inverse associations between carotenoids and lung cancer; however, the decreases in risk are generally small and not statistically significant. These inverse associations may be the result of carotenoid measurements' function as a marker of a healthier lifestyle (higher fruit and vegetable consumption) or of residual confounding by smoking.
AB - Background: Carotenoids are thought to have anti-cancer properties, but findings from population-based research have been inconsistent. Objective: We aimed to conduct a systematic review of the associations between carotenoids and lung cancer. Design: We searched electronic databases for articles published through September 2007. Six randomized clinical trials examining the efficacy of β-carotene supplements and 25 prospective observational studies assessing the associations between carotenoids and lung cancer were analyzed by using random-effects meta-analysis. Results: The pooled relative risk (RR) for the studies comparing β-carotene supplements with placebo was 1.10 (95% confidence limits: 0.89, 1.36; P = 0.39). Among the observational studies that adjusted for smoking, the pooled RRs comparing highest and lowest categories of total carotenoid intake and of total carotenoid serum concentrations were 0.79 (0.71, 0.87; P < 0.001) and 0.70 (0.44, 1.11; P = 0.14), respectively. For β-carotene, highest compared with lowest pooled RRs were 0.92 (0.83, 1.01; P = 0.09) for dietary intake and 0.84 (0.66, 1.07; P = 0.15) for serum concentrations. For other carotenoids, the RRs comparing highest and lowest categories of intake ranged from 0.80 for β-cryptoxanthin to 0.89 for α-carotene and lutein-zeaxanthin; for serum concentrations, the RRs ranged from 0.71 for lycopene to 0.95 for lutein-zeaxanthin. Conclusions: β-Carotene supplementation is not associated with a decrease in the risk of developing lung cancer. Findings from prospective cohort studies suggest inverse associations between carotenoids and lung cancer; however, the decreases in risk are generally small and not statistically significant. These inverse associations may be the result of carotenoid measurements' function as a marker of a healthier lifestyle (higher fruit and vegetable consumption) or of residual confounding by smoking.
UR - http://www.scopus.com/inward/record.url?scp=49449085278&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=49449085278&partnerID=8YFLogxK
U2 - 10.1093/ajcn/88.2.372
DO - 10.1093/ajcn/88.2.372
M3 - Article
C2 - 18689373
AN - SCOPUS:49449085278
SN - 0002-9165
VL - 88
SP - 372
EP - 383
JO - American Journal of Clinical Nutrition
JF - American Journal of Clinical Nutrition
IS - 2
ER -