A. Heather Eliassen, Sc.D., from Brigham & Women's Hospital in Boston, and colleagues analyzed pooled data from eight cohort studies, comprising more than 80 percent of the world's published prospective data on plasma or serum carotenoids and breast cancer. The analysis included 3,055 case subjects and 3,956 matched controls. Participant carotenoid levels were recalibrated to a common standard by reassaying 20 plasma or serum samples from each cohort together at the same laboratory.

The researchers found significant inverse associations between breast cancer and α-carotene (top versus bottom quintile relative risk [RR], 0.87; P_trend = 0.04), β-carotene (RR, 0.83; P_trend = 0.02), lutein+zeaxanthin (RR, 0.84; P_trend = 0.05), lycopene (RR, 0.78; P_trend = 0.02), and total carotenoids (RR, 0.81; P_trend = 0.01). There was no significant association between β-cryptoxanthin and breast cancer risk. Stronger associations were found for several carotenoids and estrogen receptor negative (ER−) tumors than for ER+ tumors; for example, for the top versus the bottom quintile of β-carotene, the RR was 0.52 for ER− and 0.83 for ER+ tumors.

"This comprehensive prospective analysis suggests women with higher circulating levels of α-carotene, β-carotene, lutein+zeaxanthin, lycopene, and total carotenoids may be at reduced risk of breast cancer," the authors write.

The study was partially funded by DSM Nutritional Products (formerly Roche Vitamins).

Abstract
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