Hsin-Hua ChenHsian-Min ChenChing-Heng LinKuo-Tung TangDer-Yuan ChenJames Cheng-Chung WeiWen-Cheng Chao2026-01-302026-01-302021-07-0110.3389/fmed.2021.704593https://scholars.csmu.edu.tw/handle/123456789/4223<jats:p><jats:bold>Objective:</jats:bold> Primary Sjögren's syndrome (pSS) is characterized by exocrine glandular inflammation; however, the association between preceding mammary-gland-inflammation-related diseases and newly diagnosed pSS remains unexplored.</jats:p><jats:p><jats:bold>Methods:</jats:bold> We used the 2003–2013 data retrieved from Taiwan's National Health Insurance Research Database (NHIRD) to conduct the present population-based study. We identified newly diagnosed pSS female patients during the 2001–2013 period, as well as age-matched (1:20) and propensity-score-matched (1:2) non-SS individuals (as controls). We explored the associations between pSS and a history of mastitis and fibrocystic breast disease by determining adjusted odds ratios (aORs) with 95% confidence intervals (CIs) using a conditional logistical regression analysis after controlling for potential confounders.</jats:p><jats:p><jats:bold>Results:</jats:bold> We identified 9,665 patients with pSS and 193,300 age-matched non-SS controls, as well as 9,155 SS cases and 18,310 propensity-score-matched non-SS controls. We found that fibrocystic breast disease (aOR, 1.75; 95% CI, 1.63–1.88) were independently associated with incident SS, whereas mastitis and childbirth-associated breast infections were not associated with incident SS. We also found positive associations between SS and previously reported SS-associated diseases, including cardiovascular diseases, thyroid diseases, pancreatitis, bronchiectasis, infectious diseases, osteoporosis, and ankylosing spondylitis. In the propensity-score-matched populations, the associations between pSS and fibrocystic breast disease (aOR, 1.74; 95% CI, 1.58–1.91) remained consistent.</jats:p><jats:p><jats:bold>Conclusion:</jats:bold> The present population-based study revealed a previously unexplored association between pSS and history of fibrocystic breast disease, and the finding highlights the need to survey pSS in patients with mammary-gland-inflammation-associated diseases.</jats:p>[SDGs]SDG3[SDGs]SDG5journal-article