Abstract and Introduction
Many people believe that weather influences chronic musculoskeletal pain. Previous studies on this association are narratively reviewed, with particular focus on comparing methodologies and summarising study findings in light of study quality. We searched 5 databases (Medline, Embase, Web of Science, PsycINFO, and Scopus) for observational studies on the association between weather variables and self-reported musculoskeletal pain severity. Of 4707 located articles, 43 were eligible for inclusion. The majority (67%) found some association between pain and a weather variable. Temperature, atmospheric pressure, relative humidity, and precipitation were most often investigated. For each weather variable, some studies found an association with pain (in either direction), and others did not. Most studies (86%) had a longitudinal study design, usually collecting outcome data for less than a month, from fewer than 100 participants. Most studies blinded participants to study aims but were at a high risk of misclassification of exposure and did not meet reporting requirements. Pain severity was most often self-reported (84%) on a numeric rating scale or visual analog scale. Weather data were collected from local weather stations, usually on the assumption that participants stayed in their home city. Analysis methods, preparation of weather data, and adjustment for covariates varied widely between studies. The association between weather and pain has been difficult to characterise. To obtain more clarity, future studies should address 3 main limitations of the previous literature: small sample sizes and short study durations, misclassification of exposure, and approach to statistical analysis (specifically, multiple comparisons and adjusting for covariates).
"Doctor, can you give me a prescription to move to Spain?" Rheumatic patients in colder midlatitude climates have received arthritis treatment in subtropical climates for centuries.[8,30,43] Between 62% and 97% of people with musculoskeletal conditions believe that the weather influences their pain.[31,58,70] Despite this belief among patients, there is no scientific consensus on the association between weather and musculoskeletal pain. Previous literature reviews on this topic have usually focused on research of 1[21,54,65] or 2 musculoskeletal conditions. Some reviews state that current evidence does not support an association between weather and pain,[39,65] whereas others show an association, although generally small and of debatable statistical and/or clinical significance.[21,46,48,54,62]
In previous reviews, aggregating study results was hampered by methodological heterogeneity.[48,54,65] For example, studies differed in choice of outcomes, exposures, and populations. Pain is subjective and individual, and researchers can focus on different aspects (eg, severity, changes, and flares). The weather can be described by many variables (eg, temperature, humidity, and pressure) that are not independent of each other. Both pain and weather change continuously but are usually measured at fixed intervals, the timing and frequency of which may differ. How these choices in individual studies are made has consequences for the study scope, design, and results. By reviewing studies on any musculoskeletal condition and considering their methodological heterogeneity, it may be possible to find patterns within studies using a similar approach and to move towards a clearer understanding of an otherwise confusing literature.
The aim of this review was to identify and synthesize studies of the association between weather variables and chronic pain in people living with musculoskeletal disease, with particular focus on the consequences of methodological choices (eg, definition of exposure and outcome, frequency and method of data collection, and statistical methods). This article is organized as follows. We first describe the literature search and the characteristics of identified published studies. Then, we summarize their findings. We highlight differences between these studies, between all studies investigating a specific weather variable (eg, temperature, pressure, and humidity), and between subpopulations (eg, per musculoskeletal disease). We then summarize and discuss the methodological heterogeneity, identifying differences in study design, collection of weather and pain data, data preparation and analysis, and risk of bias.
Pain. 2020;161(4):668-683. © 2020 Lippincott Williams & Wilkins