To prospectively analyze seasonal distribution in the onset of symptoms of polymyalgia rheumatica (PMR) and its relationship to parvovirus B19 infection.
Over a 4-year period (September 1997 to September 2001), 68 patients were prospectively diagnosed with PMR in an outpatient rheumatology department, of which only 55 patients (38 women, 17 men) aged 50 to 90 years (mean 74.1 +/- 8.1) were able to specify the month of onset of symptoms. During the last year parvovirus B19 IgM serologies were determined in all new cases.
No significant seasonal variation in disease onset was observed during the 4-year period; 17 cases were observed in spring, 10 in summer, 15 in autumn, and 13 in winter (p = 0.625). Nevertheless, almost 50% of all cases of PMR were diagnosed in the months of May, February, and August. All of the evaluated patients (14 of 14) had negative parvovirus B19 IgM serologies.
Onset of symptoms in PMR is unrelated to seasonal pattern. Yet almost 50% of cases occurred in the months of May, February, and August. Parvovirus B19 infection was unrelated to the onset of PMR.