与男性相比，女性自身免疫性疾病和乳腺癌的发病率明显更高。之前的观察性研究尚未最终确定这两种情况之间的关系。本研究利用孟德尔随机化方法来研究自身免疫性疾病与乳腺癌之间的遗传关联。使用 GWAS 数据库对欧洲人群进行双样本孟德尔随机化。逆方差加权方法是主要的分析方法。应用MR-PRESSO测试来检测水平多效性。为了确保结果的稳健性，使用了FDR校正方法。研究表明，干燥综合征可降低患乳腺癌的总体风险（OR 0.96，95% CI [0.93-0.99]，p = 0.011）。特发性炎症性肌病对整体乳腺癌具有保护作用（OR 0.98，95% CI [0.97-0.99]，p = 0.035）。类风湿性关节炎与整体乳腺癌之间存在关联（OR 0.98，95% CI [0.96-1.00]，p = 0.050）。系统性红斑狼疮、系统性硬化症和整体乳腺癌之间没有发现因果关系。该研究还表明，干燥综合征、类风湿性关节炎和特发性炎症性肌病可能会降低患 HER  乳腺癌的风险。具体来说，干燥综合征（OR = 0.90，95% CI [0.83-0.98]，p = 0.02）、类风湿性关节炎（OR = 0.94，95% CI [0.91-0.98]，p = 0.006）和特发性炎症性肌病（OR = 0.96，95% CI [0.93-0.99]，p = 0.036）。此外，系统性红斑狼疮被发现可以降低 HER-乳腺癌的风险（OR = 0.95，95% CI [0.91-0.99]，p = 0.046）。该研究并未建立这五种自身免疫性疾病与 ER  或 ER-乳腺癌之间的因果关系。这项研究发现自身免疫性疾病可能作为预防乳腺癌风险的保护因素。© 2024。作者。

The incidence of autoimmune diseases and breast cancer is significantly higher in women compared to men. Previous observational studies have not conclusively determined the relationship between these two conditions. This study utilizes the Mendelian randomization approach to investigate the genetic association between autoimmune diseases and breast cancer.Two-sample Mendelian randomization was conducted on a European population using the GWAS database. The inverse variance-weighted method served as the primary analytical approach. The MR-PRESSO test was applied to detect horizontal pleiotropy. To ensure result robustness, the FDR correction method was used.The study revealed that Sjögren's syndrome lowers the overall risk of breast cancer (OR 0.96, 95% CI [0.93-0.99], p = 0.011). Idiopathic inflammatory myopathy shows a protective effect against overall breast cancer (OR 0.98, 95% CI [0.97-0.99], p = 0.035). An association was identified between rheumatoid arthritis and overall breast cancer (OR 0.98, 95% CI [0.96-1.00], p = 0.050). No causal link was found between systemic lupus erythematosus, systemic sclerosis, and overall breast cancer. The study also suggests that Sjögren's syndrome, rheumatoid arthritis, and idiopathic inflammatory myopathy might reduce the risk of developing HER + breast cancer. Specifically, Sjögren's syndrome (OR = 0.90, 95% CI [0.83-0.98], p = 0.02), rheumatoid arthritis (OR = 0.94, 95% CI [0.91-0.98], p = 0.006), and idiopathic inflammatory myopathy (OR = 0.96, 95% CI [0.93-0.99], p = 0.036). Additionally, systemic lupus erythematosus was found to lower the risk of HER- breast cancer (OR = 0.95, 95% CI [0.91-0.99], p = 0.046). The study did not establish a causal relationship between these five autoimmune diseases and ER + or ER- breast cancer.This study found that autoimmune diseases may act as protective factors against breast cancer risk.© 2024. The Author(s).