Mustafa EKİCİ, Fatmagül Gülbahçe İNCESU, Zehra ÖZSOY, Gizem AYAN, Erdinç ÜNALDI, Büşra FIRLATAN, Gözde Sevgi Kart BAYRAM, Buğu BULAT, Levent KILIÇ, Umut KALYONCU
Rheumatology Quarterly - 2026;4(3):148-154
Objective: The pathogenesis of ankylosing spondylitis (AS) involves both genetic and environmental factors. This study aimed to investigate whether shared living spaces increase the risk of AS development in the spouses of patients with AS. Methods: The study included consecutive AS patients from the Hacettepe University Rheumatology Clinic (November 2021-June 2022) diagnosed using the Assessment of SpondyloArthritis international Society (ASAS) criteria. This research was conducted using a cross-sectional design. Spouses with reported AS were evaluated to confirm diagnoses. Confirmed AS cases were included, while undiagnosed inflammatory low back pain cases were excluded. Two rheumatologists independently assessed the spouses using pelvic radiography and sacroiliac magnetic resonance imaging, if needed. Standardized incidence ratios (SIRs) were calculated by dividing the observed number of cases by the expected number of cases, derived from age- and sex-specific incidence rates applied to the person-years at risk. Results: Among the 680 patients, 582 (85.6%) had AS, 72 (10.6%) had non-radiographic axial spondyloarthritis, and 26 (3.8%) had peripheral spondyloarthritis. The mean follow-up was 10.6 (+/-7.9) years. Spouses of 7 patients (1.2%, 95% CI: 0.5-2.5) met the ASAS criteria for AS. Excluding 2 patients diagnosed before marriage, the prevalence of AS among spouses was 5/580 (0.86%, 95% CI: 0.3-2). Over 12 635 person-years of marriage, 5 new AS cases were observed vs. 0.82 expected (SIR: 6.1, 95% CI: 2.0-14.2). Among unrelated spouses, 3 post-marriage AS cases were observed over 12 613 person-years, yielding an SIR of 3.65 (95% CI: 0.75-10.68). Conclusion: Among spouses living in the same environment, the diagnosis of AS increased by approximately sixfold. Even after excluding consanguineous couples, the incidence of AS remained higher than expected among unrelated spouses, although the statistical significance was limited by the small number of observed cases. This observation may suggest a role for shared environmental factors in the development of AS.
