To examine the nature of seasonal symptoms, their prevalence, and differences among rheumatic disorders by examining longitudinal data over a period of up to 24 years.
We used a questionnaire assessment of seasonal symptoms using the Seasonal Pattern Assessment Questionnaire (SPAQ) in 1,424 patients with rheumatoid arthritis (RA), osteoarthritis (OA), and fibromyalgia (FM). Clinical status was evaluated with standard assessment measures, and reported symptoms were compared with actual seasonal differences measured for periods of up to 24 years.
About 50% of patients with rheumatic disease reported exacerbation of rheumatic symptoms (pain, global severity, and fatigue) by seasonal changes. The presence of seasonal symptoms was not related to diagnosis or to seasonal affective disorder (SAD) symptoms, and symptoms were less common in older patients and in men. The number of symptoms and the severity of allied factors (depression, anxiety, pain, global severity, number of months with seasonal symptoms) were increased in persons with FM and/or complete SAD symptoms. Using circular statistics, the modal months for worse symptoms were December and January, and for best symptoms was July. Bimodal patterns of seasonality were identified for global severity, joint pain, fatigue, and socialization. Seasonal symptoms differed as to the degree at which they were dispersed around the 12 month circle. When pain and global severity measurements obtained over a 24 year period were analyzed, pain was slightly increased in the summer and global severity was not related to season at all. Even when patients who specifically reported worse symptoms in winter and best symptoms in summer were examined, no effect of season could be found.
Seasonal rheumatic symptoms are commonly reported across all rheumatic diseases, but appear to reflect perception rather than reality since reported symptoms do not agree with measured clinical scores. In addition, regardless of seasonal complaints, measured pain and global severity scores are not worse in winter. Although patients with FM and Season (+) patients report more severe symptoms, their pattern of reporting and their actual scores do not differ according to season compared to persons without FM or positive seasonality.