No rain, no pain: Study links foul weather with body aches

Lara Tosunlar, 37, suffers from lupus, an affliction that causes her joints to ache. The pain is sometimes agonizing, and it gets worse, she said, when the weather is poor.

"There are definitely days when it feels like you are dragging yourself even to do the most simple things - to climb a couple of steps, even to go to the bathroom. It's so much more effort on those days when it's really wet, really humid," said Tosunlar, a graduate student at King's College London. "It is such a contrast with the other days, when there is a dry heat. That's just wonderful."

When she would tell her doctors about her struggles with humid weather, they would react skeptically, and understandably so. The research on weather and joint pain is mixed at best, which is why Tosunlar was happy to take part in a wide-ranging British research project into the matter, and happier still when the results affirmed what she and so many others have long felt.

The results showed low pressure, high humidity, heavy precipitation and strong winds are associated with increased pain. In other words, people are most likely to experience aches and pains on stormy, windy days and least likely to on dry, calm days.

"I was thrilled that they did find the link with the humidity, and I agreed with the rainy days as well," Tosunlar said. "I was so excited that it gave a bit more strength to what we were all saying. It wasn't just a feeling that we had."

Researchers led by William Dixon, director of the Centre for Epidemiology Versus Arthritis at the University of Manchester, aimed to improve on prior studies that were too small or too short-lived to offer much insight. They recruited more than 13,000 people living with chronic pain conditions to take part in their 15-month study that kicked off in January 2016, appearing on British TV shows "Trust Me, I'm a Doctor" and "BBC Breakfast" to encourage people to take part. The effort was dubbed "Cloudy with a Chance of Pain."

Participants downloaded a smartphone app that tracked their location and recorded local weather conditions. Every day, they used the app to report on their level of pain, as well their mood, how well they slept, and how much time they spent outdoors, among other factors. The information they produced has yielded two papers so far.

The first paper, published in October in the journal "npj Digital Medicine," looked at the nearly 2,700 people who supplied the most consistent data to see how they fared from day to day through changing weather conditions.

A paper published this month in the Bulletin of the American Meteorological Society looked at a larger group of more than 10,000 people who entered data more sporadically. It compared conditions on days when a lot of people reported pain with days when few people reported pain.

Both studies found that people suffered more during periods of lower pressure, higher humidity and stronger wind. The more recent study also showed a link with higher precipitation. Low pressure was the most common source of pain reports, said David Schultz, a professor of synoptic meteorology at the University of Manchester and lead author of the new paper.

"When lower pressure is approaching the U.K., that's when people start to notice an increase in their pain. When there's a high-pressure pattern over the U.K., that's when people tend not to report painful events," said Schultz, recipient of the award for outstanding achievement in biometeorology from the European Meteorological Society for this research.

It could be that when the pressure drops, the fluid sacs in one's joints expand, inciting pain, though scientists can't say for sure, he said. But the effect of barometric pressure on pain was small compared to factors such as whether someone had exercised or taken their pain medication.

Geir Smedslund, a senior researcher at the Norwegian Institute of Public Health, who was not involved in the research, praised the effort for its scope. "On the positive side, I would mention that the authors managed to overcome several flaws of earlier studies, such as small samples, short observation periods and flawed statistical methods," he said in an email. Though, he said, this new analysis is far from conclusive.

"Does weather affect joint pain?" is an exquisitely difficult question to answer. There are too many variables, like the weather, that scientists can't control. Even a study as robust as this one will leave questions unanswered.

For one, pain is influenced by a host of factors, including some - such as how much one drinks - that weren't included in this study, said Robert Shmerling, a rheumatologist and senior editor at Harvard Health Publications, who was not affiliated with the research. For another, he said, people knew they were taking part in a study on weather and pain, so they may have been more likely to pay attention to their achy joints when the forecast turned.

Researchers tried to account for any such bias by asking participants if they believed weather aggravated their joints. They found no difference in reported pain between those who did and those who did not. Still, Shmerling said it would have been better if participants were not inspired to think about the weather at all. He remains skeptical of the link between weather and joint pain.

"I believe patients when they tell me they experience a connection, but I'm not sure this study moves us forward in understanding the connection between weather and arthritis," he said in an email. "It may be true for an individual that there's a correlation between the weather and joint symptoms. But, on average, that link has not been demonstrated in studies."

Shmerling said future research should account for more of the factors that affect joint pain. Smedslund, who has studied the link between weather and joint pain, said scientists should have participants wear portable weather stations to gather highly localized data, including data on conditions indoors.

Should researchers undertake such an effort in the U.K., Tosunlar said she would be eager to take part, given how much she enjoyed the University of Manchester study.

"Generally, I really loved it," she said. "I definitely learned more about myself, because it made me tune in to, 'OK, what is the weather doing today? Does it make sense that today is a worse day?' "