Previous epidemiological studies have revealed the anti-
cancer effect of dietary circulating
carotenoids. However, the protective role of specific individual circulating
carotenoids has not been elucidated. The purpose of this study was to examine whether serum
carotenoids, including α-
carotene, β-
carotene, β-
cryptoxanthin,
lycopene and
lutein/
zeaxanthin, could lower the risk for
breast cancer among Chinese women. A total of 521 women with
breast cancer and age-matched controls (5-year interval) were selected from three teaching hospitals in Guangzhou, China. Concentrations of α-
carotene, β-
carotene, β-
cryptoxanthin,
lycopene and
lutein/
zeaxanthin were measured using HPLC. Unconditional logistic regression models were used to calculate OR and 95% CI using quartiles defined in the control subjects. Significant inverse associations were observed between serum α-
carotene, β-
carotene,
lycopene,
lutein/
zeaxanthin and the risk for
breast cancer. The multivariate OR for the highest quartile of serum concentration compared with the lowest quartile were 0·44 (95% CI 0·30, 0·65) for α-
carotene, 0·27 (95% CI 0·18, 0·40) for β-
carotene, 0·41 (95% CI 0·28, 0·61) for
lycopene and 0·26 (95% CI 0·17, 0·38) for
lutein/
zeaxanthin. However, no significant association was found between serum β-
cryptoxanthin and the risk for
breast cancer. Stratified analysis by menopausal status and oestrogen receptor (ER)/
progesterone receptor (PR) showed that serum α-
carotene, β-
carotene,
lycopene and
lutein/
zeaxanthin were inversely associated with
breast cancer risk among premenopausal women and among all subtypes of ER or PR status. The results suggest a protective role of α-
carotene, β-
carotene,
lycopene and
lutein/
zeaxanthin, but not β-
cryptoxanthin, in
breast cancer risk.