Channing Division of Network Medicine, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, 181 Longwood Ave, Boston, MA 02115, USA.
J Natl Cancer Inst. 2012 Dec 19;104(24):1905-16. doi: 10.1093/jnci/djs461. Epub 2012 Dec 6.
Carotenoids, micronutrients in fruits and vegetables, may reduce breast cancer risk. Most, but not all, past studies of circulating carotenoids and breast cancer have found an inverse association with at least one carotenoid, although the specific carotenoid has varied across studies.
We conducted a pooled analysis of eight cohort studies comprising more than 80% of the world's published prospective data on plasma or serum carotenoids and breast cancer, including 3055 case subjects and 3956 matched control subjects. To account for laboratory differences and examine population differences across studies, we recalibrated participant carotenoid levels to a common standard by reassaying 20 plasma or serum samples from each cohort together at the same laboratory. Using conditional logistic regression, adjusting for several breast cancer risk factors, we calculated relative risks (RRs) and 95% confidence intervals (CIs) using quintiles defined among the control subjects from all studies. All P values are two-sided.
Statistically significant inverse associations with breast cancer were observed for α-carotene (top vs bottom quintile RR = 0.87, 95% CI = 0.71 to 1.05, P(trend) = .04), β-carotene (RR = 0.83, 95% CI = 0.70 to 0.98, P(trend) = .02), lutein+zeaxanthin (RR = 0.84, 95% CI = 0.70 to 1.01, P(trend) = .05), lycopene (RR = 0.78, 95% CI = 0.62 to 0.99, P(trend) = .02), and total carotenoids (RR = 0.81, 95% CI = 0.68 to 0.96, P(trend) = .01). β-Cryptoxanthin was not statistically significantly associated with risk. Tests for heterogeneity across studies were not statistically significant. For several carotenoids, associations appeared stronger for estrogen receptor negative (ER(-)) than for ER(+) tumors (eg, β-carotene: ER(-): top vs bottom quintile RR = 0.52, 95% CI = 0.36 to 0.77, P(trend) = .001; ER(+): RR = 0.83, 95% CI = 0.66 to 1.04, P(trend) = .06; P(heterogeneity) = .01).
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.
类胡萝卜素是水果和蔬菜中的微量营养素，可能降低乳腺癌风险。尽管具体的类胡萝卜素在不同的研究中有所不同，但大多数（但不是全部）过去关于循环类胡萝卜素与乳腺癌的研究发现，至少有一种类胡萝卜素与乳腺癌呈负相关。
我们对 8 项队列研究进行了汇总分析，这些研究包含了全球已发表的关于血浆或血清类胡萝卜素与乳腺癌的前瞻性数据的 80%以上，包括 3055 例病例和 3956 例匹配的对照。为了考虑实验室差异并研究不同研究人群的差异，我们通过在同一家实验室重新检测每个队列的 20 个血浆或血清样本，将参与者的类胡萝卜素水平重新校准到一个共同的标准。我们使用条件逻辑回归，根据乳腺癌的几个风险因素进行调整，使用所有研究中所有对照对象的五分位数来计算相对风险（RR）和 95%置信区间（CI）。所有 P 值均为双侧。
与乳腺癌呈统计学显著负相关的有α-胡萝卜素（最高五分位数与最低五分位数 RR=0.87，95%CI=0.71 至 1.05，P（趋势）=0.04）、β-胡萝卜素（RR=0.83，95%CI=0.70 至 0.98，P（趋势）=0.02）、叶黄素+玉米黄质（RR=0.84，95%CI=0.70 至 1.01，P（趋势）=0.05）、番茄红素（RR=0.78，95%CI=0.62 至 0.99，P（趋势）=0.02）和总类胡萝卜素（RR=0.81，95%CI=0.68 至 0.96，P（趋势）=0.01）。β-隐黄质与风险无统计学显著相关性。各研究间的异质性检验无统计学意义。对于几种类胡萝卜素，与雌激素受体阴性（ER（-））相比，与 ER（+）肿瘤的相关性似乎更强（例如，β-胡萝卜素：ER（-）：最高五分位数与最低五分位数 RR=0.52，95%CI=0.36 至 0.77，P（趋势）=0.001；ER（+）：RR=0.83，95%CI=0.66 至 1.04，P（趋势）=0.06；P（异质性）=0.01）。
这项全面的前瞻性分析表明，循环α-胡萝卜素、β-胡萝卜素、叶黄素+玉米黄质、番茄红素和总类胡萝卜素水平较高的女性患乳腺癌的风险可能较低。
