In his rheumatology practice, William Dixon often saw patients who complained that their arthritis pain increased when it was cold or wet. But when he puts on his epidemiologist hat, the researcher from the University of Manchester finds that very few studies, most of them methodologically weak, confirm this belief.

To overcome this thorny problem, Dr. Dixon came up with the idea of ​​developing a cell phone application that quickly collects patients’ pain levels. This made it possible to follow 2,658 people for 15 months on a day-to-day basis. And to conclude that there is indeed a link between the weather and arthritis pain, but only for humidity, atmospheric pressure and wind speed. And yet, the link was important only for humidity, reveals his study published in 2019 in the journal Digital Medicine. For every 10% increase in ambient humidity, the risk of having pain increased by 12%. The link between pain and stronger wind and lower pressure was much lower, and there was no statistically significant link with temperature.

“Since typically less than 5% of participants had pain on any given day, that means the absolute effect on the population is very modest,” says Dr. Dixon. It is surprising to see the strength of this conviction. Maybe it has to do with a general fascination with the weather. »

At the McGill University Health Center (MUHC), Yoram Shir often sees patients who strongly believe that the weather influences their pain. Too often for him to think it’s a figment of their imagination. “Usually it’s the cold that increases the level of pain,” says Dr. Shir, who heads the MUHC’s Pain Management Unit. “I would say a quarter of my patients report this link. Some have more pain when it is hot, but this is rare. I am thinking in particular of a patient who never has pain in the winter when he spends time in Phoenix, Arizona, but whose pain returns as soon as he returns to Montreal. »

Is it possible that the apprehension of pain in cold weather is enough to create pain-inducing anxiety? “Yes, it is likely that there is an anxiety-inducing effect of the weather. Another patient of mine reports that when he drives back from Florida, his pain increases the closer he gets to Canada. »

Karl Messlinger is one of the few researchers to have devoted part of his career to the mechanism that could link pain and weather. The rheumatologist from the University of Nuremberg, whose latest study on the subject was published in 2021 in the journal Cephalalgia, focuses on the links between the sinuses and areas of the brain linked to sensitivity, the meninges, which are part of the brain envelope.

“It’s hard to imagine that the different components of the weather can influence solid areas of the human body, through the skin,” says Dr. Messlinger. So it has to be an empty area. The sinuses are a great place, because they are connected to the mouth, nose, and ears. Our hypothesis is that the sinuses are related to the meninges and that the latter play an important role in sensitivity. Including in pain sensitivity. So, when we suffer more because of the weather, it is because we are more sensitive to pain. »

If the link between weather, sinuses, meninges and pain that the German researcher proposes turns out to be true, he thinks that there could be tests of molecules targeting the neurons between the sinuses and the meninges, to try to defuse this increased sensitivity.

When you Google the keywords “pain” and “weather”, you come across a host of migraine sites. Elizabeth Leroux, a Montreal neurologist who specializes in migraine, thinks it’s a problem. “When I was in Alberta, everyone wanted to hear about the Chinook,” says Dr. Leroux. There may be some real associations between weather and pain, but even more cognitive biases. This is a very sensitive subject that involves the control of patients over their symptoms. Attention to the weather does not help anyone, and it even harms by devoting attention to this aspect that is completely variable and beyond our control. I have never seen a patient benefit from weather awareness. It can be harmful by promoting anxiety and hypervigilance. »

Dr. Leroux believes that migraine care in Quebec lags behind other industrialized countries, and even other provinces. “It seems to me that the waiting lists, the lack of treatment coverage, the lack of training of neuro residents and doctors should be of more concern to people than the weather. »