Background Triple-negative breast cancer (TNBC) has a poor prognosis compared to other breast cancer subtypes. This systematic review and meta-analysis examines whether known risk factors for breast cancer are also associated with TNBC in adult females. Methods EMBASE, Medline, SCOPUS, and grey literature were queried with no limit on the date or language of publication. The exposures of interest included parity, breastfeeding, duration of breastfeeding, age at menarche, age at first live birth, oral contraceptive (OC) use, duration of OC use, use of menopausal hormone therapy (MHT), family history, body mass index (BMI), alcohol use, smoking and breast density. The main outcome of interest was TNBC. Study quality was determined using the Newcastle-Ottawa scale for case control studies and cohort studies. We estimated weighted odds ratios from random effects models to study the exposure-outcome associations. Protocol was registered under the number: PROSPERO 2021 CRD42021254594. Results Thirty-three studies were included. Family history, longer duration of oral contraceptive use, and higher breast density were significantly associated with increased risk for TNBC, whereas, later age at menarche, later age at first birth and breastfeeding were protective against TNBC. Parity, MHT, alcohol, smoking, and BMI were not significantly associated with TNBC overall, but higher parity was associated with higher risk among Black women. Conclusion Our findings highlight that TNBC has a distinct risk-factor profile compared to overall breast cancer. This can be the foundational work in identification of actionable TNBC risk factors to improve prevention and early detection of these poor prognosis breast tumors.

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三阴性乳腺癌的独特危险因素：综合荟萃分析

背景 与其他乳腺癌亚型相比，三阴性乳腺癌（TNBC）的预后较差。这项系统回顾和荟萃分析探讨了已知的乳腺癌危险因素是否也与成年女性的 TNBC 相关。方法 查询EMBASE、Medline、SCOPUS、灰色文献，发表日期、语言不限。感兴趣的暴露包括胎次、母乳喂养、母乳喂养持续时间、初潮年龄、首次活产年龄、口服避孕药 (OC) 使用、OC 使用持续时间、绝经激素治疗 (MHT) 的使用、家族史、体重指数(BMI)、饮酒、吸烟和乳房密度。人们感兴趣的主要成果是 TNBC。研究质量是使用纽卡斯尔-渥太华量表进行病例对照研究和队列研究来确定的。我们根据随机效应模型估计了加权优势比来研究暴露与结果之间的关联。协议注册号为：PROSPERO 2021 CRD42021254594。结果 纳入了 33 项研究。家族史、较长的口服避孕药使用时间和较高的乳房密度与 TNBC 风险增加显着相关，而初潮年龄较晚、初产年龄较晚和母乳喂养对 TNBC 具有保护作用。总体而言，胎次、MHT、酒精、吸烟和体重指数与 TNBC 没有显着相关，但胎次越高，黑人女性的风险越高。结论 我们的研究结果强调，与整体乳腺癌相比，TNBC 具有独特的危险因素特征。这可以成为识别可操作的 TNBC 危险因素的基础工作，以改善这些预后不良的乳腺肿瘤的预防和早期发现。