ObjectivesTo study the clinical characteristics of primary Sjögren's syndrome (pSS) with different onset age, and perform a review of the literature to confirm if the clinical phenotypes are affected by onset age in patients with pSS.
MethodsData of 742 patients with pSS were retrospectively analysed. Patients were divided into three groups according to onset age: young-onset pSS (YopSS, <35 years), ≥35 and ≤65 years), and elderly-onset pSS (EopSS, >65 years). Clinical characteristics were compared among three groups and further multiple comparisons were conducted by Bonferroni adjustment. The Chi-squared test for linear-by-linear association was used to explore variation tendency.
ResultsThis study included 105 (14.2%), 533 (71.8%), and 104 (14.0%) cases of YopSS, AopSS, and EopSS, respectively. YopSS demonstrated lower prevalence of dry mouth, abnormal Schirmer I tests, and interstitial lung disease (ILD), but higher proportions of low C3 and C4 levels, and ANA, and rheumatoid factor (RF)
positivity than AopSS andEopSS. The proportions of dry mouth (p=0.004), abnormal Schirmer I tests (p=0.002), and ILD (p<0.001) tended to increase with the increase of onset age, while the prevalence of leukopenia (p=0.011), low C3 (p=0.001), low C4 (p=0.001), and ANA (p<0.001), and RF (p<0.001) positivity tended to decrease with an increase in onset age.
ConclusionsYopSS demonstrated less dryness and ILD, but more immunologic disorders. ILD prevalence were directly proportional to onset age of pSS; however, leukopenia, hypocomplementaemia, and autoantibody positivity showed opposite trends.