Blame it on the weather?
Self-reported pain levels in patients with fibromyalgia may change according to weather conditions.
Previous studies suggest that atmospheric pressure also called low barometric pressure (BMP) is significantly related to increased pain, but that has limited clinical relevance. Some studies report that there is a significant association between pain levels, temperature, BMP and/or relative air humidity in chronic pain conditions, whereas other studies failed to find such relationships
This study examined whether BMP influenced changes in perceived stress, and if stress levels affected the pain.
Forty-eight patients with fibromyalgia enrolled in a randomized controlled trail.
They reported their pain and emotional state three times daily for 30-consecutive days before the start of the treatment in the RCT. .
The patients were unaware that weather data were collected simultaneously with pain and emotional reports. Both the experimenters and patients in the present study were uninformed about the plan to investigate the effects of meteorological variables on pain and stress levels.
The results showed that:
- both lower BMP and increased humidity were significantly associated with increased pain intensity.
- only BMP was associated with stress levels.
- higher stress was associated with higher pain.
- significant individual differences were present shown by a sub-group of patients (n = 8) who reacted opposite compared to the majority of patients (n = 40) with increased pain reports to an increase in BMP.
- in summary, lower BMP was associated with increased pain and stress levels in the majority of the patients, and stress moderated the relationship between BMP and pain at the group-level. Significant individual differences in response to changes in BMP were present, and the relation between weather and pain may be of clinical relevance at the individual level.
The study included data from the 48 patients The mean age of the sample was 48.6 years.
The patients had to be 18 years of age or older, diagnosed with fibromyalgia according to the ACR-90 criteria, and a manual examination of the patients’ tender points was performed before inclusion. If patients were using prescribed medication, the use had to be stable for 3 months before inclusion.
Depression and anxiety, general symptoms of psychological distress , impact of fibromyalgia on daily functioning and health-related quality of life were measured at baseline (day 1) before the measurement period.
In the morning (9 AM), afternoon (3 PM), and evening (9 PM), the patients received an SMS consisting of the following 4 questions:
- “what is your pain level now?,”
- “how unpleasant is the pain now?,”
- “how tense are you now?,” and
- “how anxious are you now?.”
All meteorological data were obtained from the Norwegian Meteorological Institute of Tromsø. The station was operated in compliance with the ICO-certified quality control procedure Obskval.
Air temperature was measured at 2m above ground level using a standard PT100 sensor. Relative humidity was measured at 2 m above ground level using a HMP45D. Atmospheric pressure (BMP) at station ground level was measured using a digital barometer PTB220A .
Both barometric pressure and relative humidity had a significant impact on the individual slopes for pain reports. Increased barometric pressure was the only weather parameter that significantly affected emotional measures.
DISCUSSION - Pain and emotional data
- a decrease in barometric pressure was associated with increased pain
- an increase in relative humidity was associated with higher pain reports
- The interaction between BMP by humidity reached significance in the pain intensity data, but was non-significant in the pain unpleasantness data.
- Higher BMP and higher levels of humidity were associated with increased pain intensity
- humidity had no impact on pain intensity levels when BMP was lower.
- The interaction between BMP and temperature was significant in both the pain intensity and the pain unpleasantness data.
- The combination of lower BMP and reduced temperature was associated with heightened pain unpleasantness compared to when BMP was higher and increased temperature.
- No other interactions including the three-way interaction between the weather variables reached significance.
The results from the present study showed that data for pain levels, emotional measures and weather conditions were significantly associated.
In summary, the present study suggests that barometric pressure influences pain in fibromyalgia but on an individual basis that is associated with emotional factors.
Blame it on the weather? The association between pain in fibromyalgia, relative humidity, temperature and barometric pressure.
Fagerlund AJ, Iversen M, Ekeland A, Moen CM, Aslaksen PM.
2019; 14(5): e0216902.
Published online 2019 May 10. doi: 10.1371/journal.pone.0216902