Weather and the pain in fibromyalgia: are they related?

OBJECTIVES To examine the association between fibromyalgic pain and weather to determine the nature of their interrelationship. METHODS The daily pain ratings of 55 female patients previously diagnosed with fibromyalgia were recorded on visual analogue scales (VAS) over 28 days. These ratings were then related to the official weather parameters and a composite weather variable using time series methodology. Effect sizes r were calculated from the t values and df. RESULTS A composite weather variable did not significantly predict changes in pain, either the same day (t=-1.15, df=1483, p=0.25) or on the next day (t=-1.55, df=1483, p=0.12)-that is, the weather was not a factor for changes in the subjective pain of FM. Patients' pain did not predict weather change in this sample, and neither same day (t=-0. 69, df=1483, p<0.49) nor previous day pain (t=-1.31, df=1483, p<0.19) predicted weather changes. A post hoc exploratory analysis showed that those with <10 years of fibromyalgia experienced significantly greater weather sensitivity to pain (t=- 2.73, df=389, p<0.006) than those with longer illness. CONCLUSION A statistically significant relationship between fibromyalgic pain and the weather was not found in this sample, although it is possible that a group of patients with less chronic fibromyalgia might be weather sensitive.