咖啡因摄入量与绝经后女性乳腺癌
咖啡因摄入量与预防和促进乳腺癌的机制都密切相关，而关于咖啡因摄入量对绝经后女性乳腺浸润癌发病率的影响，既往小样本短期随访研究结果又互相矛盾。
2021年8月21日，国际抗癌联盟《国际癌症杂志》在线发表美国纽约州立布法罗大学的大样本长期随访研究报告，分析了咖啡和茶的咖啡因摄入量对绝经后女性乳腺浸润癌发病率的影响。
该研究对1993～1998年参加女性健康倡议（WHI）时无癌症史且提供咖啡或茶摄入量的7万9871例绝经后女性随访至2015年9月30日。根据参与者自己报告每天杯数（在美国，传统1杯为8盎司约237毫升，法定1杯为240毫升）和每种饮料平均咖啡因含量估算每天来自咖啡（包括低咖啡因咖啡）或茶的咖啡因摄入量。利用多因素比例风险回归模型对年龄、种族和民族、学历、吸烟史、酒精摄入量、总能量摄入量、健康饮食替代指数、休闲体育运动、体重指数、睡眠时长、乳腺癌家族史、口服避孕药史、激素治疗用药史、初次月经年龄、首次足月分娩年龄、活产数量等其他影响因素进行校正后，推算不同咖啡因摄入量的乳腺浸润癌风险比和95%置信区间。根据亚组分析，探讨咖啡因摄入量与乳腺浸润癌的相关性是否因年龄、种族和民族、吸烟史、体重指数、激素治疗用药史、酒精摄入量和乳腺癌亚型而异。
结果，中位随访16.0年期间共确定新发乳腺浸润癌4719例。
对人口特征、生活方式和生育因素进行校正后，咖啡和茶的咖啡因摄入量与乳腺浸润癌发病率未见显著相关性（趋势P=0.54）。
与每天咖啡因摄入量≤5毫克相比：
每天咖啡因摄入量6～141毫克：乳腺浸润癌发病风险相似（风险比：1.03，95%置信区间：0.94～1.12）
每天咖啡因摄入量142～342毫克：乳腺浸润癌发病风险相似（风险比：1.04，95%置信区间：0.95～1.13）
每天咖啡因摄入量≥343毫克：乳腺浸润癌发病风险相似（风险比：1.03，95%置信区间：0.94～1.13）
每天普通咖啡、低咖啡因咖啡、茶的摄入杯数与乳腺浸润癌发病风险亦未见显著相关性。
因此，该大样本长期随访研究结果证实，咖啡因摄入量对绝经后女性乳腺浸润癌发病风险的影响不大。
Int J Cancer. 2021 Aug 21. Online ahead of print.
Caffeine Intake from Coffee and Tea and Invasive Breast Cancer Incidence among Postmenopausal Women in the Women's Health Initiative.
Zheng KH, Zhu K, Wactawski-Wende J, Freudenheim JL, LaMonte MJ, Hovey KM, Mu L.
University at Buffalo, The State University of New York, Buffalo, New York, USA.
Research findings remain inconsistent whether caffeine consumption is associated with invasive breast cancer. We aimed to examine the association between caffeine intake from coffee and tea and incident invasive breast cancer among postmenopausal women. We included 79 871 participants in the Women's Health Initiative Observational Study in the current analysis. Incident invasive breast cancers were identified through September 30, 2015. Caffeine intake (mg/day) from caffeinated and decaffeinated coffee and tea was estimated based on self-reported frequency (cups/day) and average caffeine amount in each beverage. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Subgroup analyses were conducted to explore whether associations of caffeine intake from coffee and tea with invasive breast cancer were different by age, race and ethnicity, smoking status, body mass index, history of hormone therapy use, alcohol intake, and subtypes of breast cancer. During a median follow-up of 16.0 years, 4719 incident invasive breast cancers were identified. No significant association was found between caffeine intake from coffee and tea and invasive breast cancer incidence after adjusting for demographic, lifestyle, and reproductive factors: HRs (95% CIs) for increasing quartiles of caffeine intake compared to the lowest were 1.03 (0.94, 1.12), 1.04 (0.95, 1.13), and 1.03 (0.94, 1.13), respectively (P-for-trend = 0.54). No significant associations of coffee and tea intake (cups/day) with overall breast cancer risk were found. Our findings are consistent with others showing no clear association of caffeine consumption with invasive breast cancer among postmenopausal women.
KEYWORDS: Caffeine; Coffee; Invasive Breast Cancer; Postmenopausal Women
PMID: 34418085
DOI: 10.1002/ijc.33771