Q: My friend swears that changes in the weather cause her joints to ache more than usual. Is this real or just a myth?
A: The belief that weather affects aches and pains in the joints is longstanding. But there is no convincing science to back that up.
The question of whether there's a link between weather and aches and pains has been studied extensively. While a definitive answer is nearly impossible to provide -- because it's hard to "prove a negative" (prove that something doesn't exist) -- researchers have been unable to make a strong case for a strong connection.
A recent study finds no connection between rainy weather and symptoms of back or joint pain. This conclusion was based on a staggering amount of data: more than 11 million medical visits occurring on more than two million rainy days and nine million dry days. Not only was there no clear pattern linking rainy days and more aches and pains, but there were slightly more visits on dry days.
An earlier Australian study found no link between back pain and rain, temperature, humidity or air pressure. This study collected data regarding features of the weather at the time of first symptoms, and compared it to the weather a week and a month before. But, a different study found that among 200 patients followed for three months, knee pain increased modestly when temperature fell or barometric pressure rose.
It's worth remembering that humans have a remarkable tendency to remember when two things occur or change together (such as wet, gloomy weather and joint pain), but remember less when things do not occur together. That rainy day when you felt the same as you usually do is unlikely to be so notable that you remember it. If you rely solely on memory rather than on more rigorous, data-based evidence, it's easy to conclude a link exists where, in fact, none does.
When my patients tell me they can predict the weather by how their joints feel, I believe them. It's hard to discount it when so many people notice a connection. They could represent an exception to what the studies show. But I also believe the science. Until I see evidence that's even more compelling, I remain a skeptic about the weather and arthritis connection.
(Robert H. Shmerling, M.D., is associate professor of Medicine at Harvard Medical School and clinical chief of Rheumatology at Beth Israel Deaconess Medical Center in Boston. For additional consumer health information, please visit www.health.harvard.edu.)