Epidemiological features of subjects with incident primary Sjögren syndrome (pSS) diagnosed in Olmsted County, Minnesota, USA, from 2000 to 2015, and age- and sex-matched controls without pSS.
| Baseline Characteristics | Cases, n = 106 | Controls, n = 318 | p |
|---|---|---|---|
| Age, yrs, mean (SD) | 59.7 (15.8) | 59.7 (15.7) | > 0.999 |
| Sex, female | 88 (83) | 264 (83) | > 0.999 |
| Ocular symptoms | 95/106 (90) | — | |
| Oral symptoms | 89/106 (84) | — | |
| Antinuclear antibody positivity | 77/104 (74) | — | |
| SSA (anti-La) positivity | 78/101 (77) | — | |
| SSB (anti-Ro) positivity | 61/100 (61) | — | |
| Rheumatoid factor positivity | 50/90 (56) | — | |
| Hypergammaglobulinemia present | 42/85 (49) | — | |
| Abnormal ocular staining† | 10/15 (67) | — | |
| Schirmer’s test ≤ 5/5 min | 7/9 (78) | — | |
| Abnormal salivary scintigraphy or parotid sialography | 7/9 (78) | — | |
| Unstimulated salivary flow ≤ 0.1 ml/min | 1/1 (100) | — | |
| Histopathology positivity$ | 9/14 (64) | — | |
| Met AECG criteria†† | 19 (18) | — | |
| Met 2012 ACR criteria†† | 18 (17) | — | |
| ESSDAI score | |||
| Low disease activity (≤ 5) | 42 (70) | — | |
| Moderate disease activity (5–13) | 13 (22) | — | |
| High disease activity (≥ 14) | 5 (8) | — | |
| Smoking status at index date* | 0.012 | ||
| Never smoker | 49 (46) | 140 (45) | |
| Former smoker | 51 (48) | 117 (38) | |
| Current smoker | 6 (6) | 51 (17) | |
| Smoking status 1 year prior to index date* | 0.005 | ||
| Never smoker | 48 (46) | 138 (45) | |
| Former smoker | 52 (50) | 116 (38) | |
| Current smoker | 5 (5) | 51 (17) | |
| BMI at index date, kg/m2**, mean (SD) | 27.9 (7.2) | 29.2 (7.4) | 0.062 |
| Obesity (BMI ≥ 30 kg/m2) at index date** | 33 (32) | 113 (37) | 0.318 |
Values are the number/total number (%) unless otherwise indicated.
↵† Van Bijsterveld score ≥ 4 or Rose Bengal test.
↵$ According to the report of the revising pathologist.
↵†† A minority of the patients fulfilled AECG (18%) and ACR (17%) classification criteria because the requisite tests were not performed, not because they were negative.
↵* Among cases, smoking status at date of diagnosis and 1 year prior to diagnosis date was available in all (100%) and in 105 (99%) of subjects, respectively, and among controls in 308 (97%) and 305 (96%) of subjects, respectively.
↵** BMI within 1 year before to 1 year after date of diagnosis was available for 104 cases (98%) and 304 controls (96%). AECG: American-European Consensus Group; ACR: American College of Rheumatology; ESSDAI: European League Against Rheumatism SS Disease Activity Index; BMI: body mass index.