Confirming Whether Weather Changes Change Osteoarthritis Pain Intensities

Winter Flareups of Pain: A Myth to Science but a Reality to People with Osteoarthritis

Old habits die hard, superstitions stay longer. Most individuals grow up having certain beliefs and sentiments that they strongly cling onto most times. Such sentiments are even stronger for sports personalities, celebrities and politicians who stick by certain principles believing it to bring about good luck. Common man too has a few ones on his own and the most common of them is to never allow a cat cross across your path! When it comes to health too, we have our own perceptions-some wear the same colour dress while going for a blood sugar test and some others believe that weather changes increase the degree of pain in individuals with osteoarthritis. They are even super confident about this, challenging physicians that they can predict the weather reports even better than the meteorological department but science has always doubted this belief and even research doesn’t support this.
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Sophisticated medical equipment and latest technological skills equip physicians to save as much life as possible but the common man finds it assuring and satisfying to rely upon his/her proposed theories finding comfort in their own assessment. The anecdotal link between weather and pain remain unaffected by these sophistications in technology but researchers continue to figure out the weather sensitivity in people with arthritis-results are still inconclusive till date.

Weather & Knee Osteoarthritis
Pain due to osteoarthritis is episodic and patients often complain that weather changes in terms of chillness, air humidity and barometric pressure have the capacity to increase it. Patients with other chronic conditions have reported in similar lines and has been even more dominant in those residing in places where climate changes are frequently experienced. We do have studies supporting the link between arthritis and climate change but the magnitude of association was not clearly stated and pain levels were decided only depending on self-reports rather than scientific measurements.  A study by Timmermans et al. has shown a weak but significant link between humidity and joint pain but no positive relationship between temperature and pain in direct contrast to the study by McAlindon et al. who showed that changes in temperature and atmospheric pressure increases pain intensity in people with knee osteoarthritis.

A research team in Australia conducted a web-based case-crossover study to study the increase in osteoarthritic pain due to weather changes. Online ads for participation was posted and individuals were also invited using database of participants of previous studies on knee arthritis. A total of 345 of them were recruited using inclusion criteria such as minimum age limit of 40 years, suffering from knee pain at least 5 times/week with fluctuating intensity, must meet at least one of the American College of Rheumatology criteria for knee osteoarthritis, suffer from tibiofemoral or patellofemoral osteoarthritis and should be able to access the internet. All the participants were clarified on the goal of the study-to be able to find out the trigger factors, specific weather factors, that could aggravate pain. Each participant was asked to fill an online questionnaire on demographic and clinical data at baseline and every 10 days up to 90 days of study. They were asked to quote when the knee pain was minimal, when it was moderate and when it soared to maximum before start of study. During study, each of them were asked to enter details in the study website whenever they experienced debilitating knee pain that lasted for more than 8 hours. Increase in pain levels were measured via a Pain Numeric Rating Scale (NRS 0-10) defined as an increase of ≥2 on a 0-10 NRS in comparison to the mildest pain at baseline. ‘Pain at its mildest’ was used as the basic platform for comparison and participants were asked to provide zip codes of their location when they experienced knee pain exacerbation. The team defined hazard and control periods based on their previous research of gout risk that changed with weather and index data was calculated based on them for making assessments. Climate data was procured not only for the specific period but for 3 days preceding the index data as exacerbations don’t occur instantly after exposure to a specific weather.

Results
Of the 345 included 174 of them did not experience any pain exacerbation during the study period and hence were excluded from the analysis. The effect was finally studied on the remaining 171 participants (aged around 60 years with 64% belonging to the female gender) who contributed to a total of 404 counts of pain exacerbation (hazard periods) and 1021 control periods. Each of those participating suffered from knee osteoarthritis for 10.5 years with the mean age of diagnosis around 51 years. It was mostly the right knee that frequently remained as the commonly symptomatic knee.

At the start of study all the participants reported their pain intensity to be around 4.9 that increased to 8.3 when it was worse reducing to 2.9 when it was mildest. The average exacerbation intensity reported was 5.9 on the 10-point scale. Surprisingly, high temperatures 3 days before index date prompted increase in knee pain exacerbation. For instance, compared to 10-20-degree temperature measures the risk for increased knee pain increased, almost doubled, for temperature measures of 30 degree and above. But there was no link seen between other weather factors such as relative air humidity, precipitation and barometric pressure and knee pain increase risk. The study shows that despite repeated insistence by patients that weather changes affect pain intensity the results here show that weather factors don’t affect pain intensity in any way.

Pressure & Temperature Changes Influence Osteoarthritis Pain
A study on 205 participants with confirmed knee osteoarthritis focused on the relationship between arthritis pain and meteorological conditions. Each of them belonged to different parts of USA and also participated at different times of the year. The fact that weather influence was a part of the research was publicised to the participants only after the study to avoid any report bias. The studies focused on the relationship of pain with weather not only with ambient conditions but also with changes in conditions immediately before any pain report was delivered.

Pain assessment was made using questionnaires given every 2 weeks amounting to 7 assessments with scores between 0 and 20 reporting different pain levels experienced during different daily activities. Meteorological data was also collected. After imposing inclusion criteria 200 individuals were eligible for participation, their mean age was around 60 and more than 60% were females. Baseline pain score was around 9 and they provided a total of 935 pain reports. Results showed that both, barometric pressure and ambient temperature had insignificant effect on pain exacerbations. For instance, a temperature of 10 °F decrease increased knee pain score of 0.1. The study also noted that increasing barometric pressure was associated with increased pain. A study by Wilder et al. on 154 individuals with osteoarthritis showed positive associations with days of rising barometric pressure in the participants. But another study by Strusberg et al. found a positive link between pain and low ambient temperature but observed no impact of pressure. The researchers of the present study found their results to be similar to that of another researcher, Hollander who suggested that increase in humidity following a decrease in barometric pressure increased pain, swelling and stiffness in those suffering from arthritis.

Yet another study by Barrett et al. on participants aged 49 years and above also did not support the assumption that weather changes including barometric pressure, precipitation and temperature had any effect on pain intensity in patients with arthritis.

All these contradictory results against weather impact on pain levels make us wonder whether people have got it wrong or if they are the exceptions. But I have seen my own mother suffering from increased pain in her joints during winter! Its hard to let go of this theory when there are thousands of people reporting changes in pain intensities linked to weather changes. Could they all be an exception? Hardly! So, have researches always excluded these exceptions while conducting their studies? Science is showing us with hard-core facts that there is no link between weather changes and pain intensity changes in those suffering from osteoarthritis. On one hand we believe in our people and on the other hand we definitely believe in scientific evidence. While trust makes us support these people with arthritis who blame weather on increased pain levels we cannot come to definite conclusions unless we have more compelling evidence scientifically.
 
References
The Influence of Weather on the Risk of Pain Exacerbation in Patients with Knee Osteoarthritis: https://www.sciencedirect.com/science/article/pii/S1063458416302059
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Changes in Barometric Pressure and Ambient Temperature Influence Osteoarthritis Pain: https://www.amjmed.com/article/S0002-9343%2806%2901026-6/pdf

Osteoarthritis Pain & Weather: https://academic.oup.com/rheumatology/article/42/8/955/1774101