Gender difference of primary Sjögren’s Syndrome in a Chinese cohort: Why do women suffer more?

Objective: T o analyze gender differences in clinical characteristics of patients with pSS and to identify potential influencing factors. Methods: We analyzed gender differences in clinical variables of 278 pSS patients diagnosed in the Department of Rheumatology and Immunology, Tongji Hospital from January 2010 to December 2020. Then Mendelian randomization (MR) analyses were conducted. Results: 92.1% of the 278 pSS patients were women. Women developed the disease earlier and were diagnosed at a younger age. The average age at which women first develop symptoms of pSS was 48.16 years, compared with 57.86 years for men ( P = 0.002). Men were diagnosed with pSS on average about 10 years later than women. Females showed a higher complement C3 ( P = 0.033), total cholesterol (TC) ( P = 0.003), low-density lipoprotein cholesterol (LDL-C) ( P = 0.013) and high-density lipoprotein cholesterol (HDL-C) ( P = 0.024), while male showed a higher fasting plasma glucose (FPG) ( P = 0.013). Females showed a lower incidence of hypertension ( P = 0.006), diabetes ( P = 0.019), coronary heart disease ( P = 0.038), cerebral infarction ( P = 0.005) and malignant cancer ( P < 0.01). MR-Egger method suggests that the decreased pSS risk was affected by TT (OR = 0.598, P = 0.048) and BT (OR = 0.471, P = 0.032). Conclusion: Females were more likely to develop pSS at an earlier age with fewer comorbidities, which might be closely related to lower levels of testosterone in women. Males showed a higher incidence of hypertension, diabetes, coronary heart disease, cerebral infarction, and malignant cancer.