Background Ankylosing spondylitis (AS) is a chronic inflammatory disease which mainly involves sacroiliac joints, resulting in pain, functionally limitation and even less life expectancy. Seasonal variation was found in rheumatoid arthritis and gout [1,2]. No reports had been focused on seasonal variation of AS onset or symptoms in AS patients.

Objectives Our study was to investigate the relationship of seasonal variation and the onset and symptoms of AS in Chinese patients.

Methods Adult AS patients diagnosed with the modified New York criteria for AS whose disease duration was over 2 years were enrolled from several provinces all over China. Participants were required to complete a set of questionnaires and examinations, including demographic and clinical information. Questions included “in which season(s) did you have the initial symptoms of AS”, and “in which season(s) were the symptoms aggravated/improved”. The Statistical Package for Social Sciences (SPSS) software version 21 was used for all data management and analysis.

Results Of all the 859 AS patients, 75.1% were male patients. 47.8% were married. Mean age was 30.60±9.50 years. Mean disease duration was 7.43±6.92 years. 27.7% of the patients had an onset of the disease in summer, while the lowest incidence happened in autumn (12.5%, p<0.05). 29.6% of the patients could not recall the exact season. 29.5% of the patients' symptoms got worse in winter, while only 2.6% of the patients felt worse in autumn, in comparison of 10.3% in spring and 6.0% in summer. 24.4% of the patients felt relieved in summer, while surprising, only 2.7% felt better in spring, with a lowest rate in the four season. However, 48.1% of the patients believed there were no seasonal differences.

Conclusions More patients had an onset of AS in summer, compared to other seasons. More patients felt worse in winter and better in summer. Nearly half of AS patients considered that there were no seasonal differences in the deterioration or improvement of the symptoms.

References

1. Karmacharya P, Pathak R, Aryal MR, Giri S, Donato AA (2016) Seasonal variation in acute gouty arthritis: data from Nationwide Inpatient Sample. Clin Rheumatol 35: 523–525.

2. Feldthusen C, Grimby-Ekman A, Forsblad-d'Elia H, Jacobsson L, Mannerkorpi K (2016) Seasonal variations in fatigue in persons with rheumatoid arthritis: a longitudinal study. BMC Musculoskelet Disord 17: 59.

References

Disclosure of Interest Y. Jiang: None declared, M. Yang: None declared, Z. Lin: None declared, Q. Wei: None declared, S. Cao: None declared, J. Gu Grant/research support from: Guangzhou Science and Technology Plan Projects [grant number 2006Z2-E0221] and 5010 Subject of Sun Yat-sen University (2009–2010)