A two-year cohort study
Dorleijn DM, et al.
Pain. 2014 Jan 22. pii: S0304-3959(14)00026-8. doi: 10.1016/j.pain.2014.01.018. [Epub ahead of print]
Abstract
The goal was to assess whether there is an association between ambient weather conditions and patients’ clinical symptoms in patients with hip osteoarthritis (OA). The design was a cohort study with a 2-year follow-up and 3-monthly measurements and prospectively collected data of weather variables. The study population consisted of 222 primary care patients with hip OA. Weather variables included temperature, wind speed, total amount of sun hours, precipitation, barometric pressure, and relative humidity. The primary outcomes were severity of hip pain and hip disability measured with the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) pain and function subscales. Associations between hip pain and hip disability and the weather variables were assessed using crude and multivariate adjusted linear mixed-model analysis for repeated measurements. On the day of questionnaire completion, mean relative humidity was associated with WOMAC pain (estimate 0.1; 95%CI 0.0-0.2; p 0.02). Relative humidity contributed ⩽1% to the explained within-patient variance and between-patient variance of the WOMAC pain score. Mean barometric pressure was associated with WOMAC function (estimate 0.1; 95%CI 0.0-0.1; p 0.02). Barometric pressure contributed ⩽1% to the explained within-patient variance and between-patient variance of the WOMAC function score. The other weather variables were not associated with the WOMAC pain or function score. Our results support the general opinion of OA patients that barometric pressure and relative humidity influences perceived OA symptoms. However, the contribution of these weather variables (⩽1%) to the severity of OA symptoms is not considered to be clinically relevant.