Here’s What ‘Big Data’ Reveals About the Link Between Rainy Days and Joint Pain

An analysis of Medicare and National Oceanic and Atmospheric Administration data found fewer visitations for joint and back pain on rainy days than on dry days.

It’s a popular theory: When it rains, a person’s joints are more likely to become sore or their back to begin aching.

“I think most doctors have heard this from a lot of people,” Anupam Jena, an associate professor at Harvard Medical School, told Seeker. The association, Jena added, goes as far back as ancient Greece.

Jena and several colleagues set out to see if there was any scientific basis behind the connection between weather and physical ailments.

“There are hypothesis that all these things could be linked and so the question is whether or not they are true,” Jena said. “We can’t definitely say that it’s not true — all that we can say is there is a way to look at this question leveraging data on millions and millions of Americans and linking it to precipitation data.”

The team started with Medicare data from more than 11 million outpatient visits for joint or back pain between 2008 and 2012. All of the roughly 1.5 million participants in the study were over the age of 65.

The researchers combined the Medicare data with information on precipitation during that time from the National Oceanic and Atmospheric Administration’s Global Historical Climatology Network Daily database. Using the latitude and longitude of a patient’s zip code, they then matched each location to the nearest weather station and found that 18 percent of visits occurred on rainy days.

Armed with these sets of “big data,” the researchers analyzed the numbers to see if visits for joint or back pain increased during a rainy day. The researchers also looked at days where there was no rainfall, but precipitation may have occurred during that week or a preceding week.

“We hypothesized that if a true relation between rainfall and joint or back pain exists, patients might be more likely to either acutely seek care from their internists for these conditions during rainy periods or mention these symptoms when seeing an internist during a previously scheduled outpatient visit,” the researchers wrote.

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After considering a patient’s age, sex, ethnicity, and chronic conditions like rheumatoid arthritis, the researchers found that there was no statistically significant relation between the number of claims for joint or back pain and the number of rainy days in a week.

When looking at the number of claims made during rainy days verses non-rainy days, the researchers found that there were actually fewer claims made during rainy days: 6.35 percent of the office visits included reports of pain on rainy days compared to 6.39 percent on dry days.

The research, funded by the National Institutes of Health and the National Institute on Aging, was published in the journal BMJ.

The doctors acknowledged that they lacked detailed information on the severity of a patient’s ailment or the drugs they might have been taking to mitigate pain.

Jena said that people with chronic conditions like rheumatoid or osteoarthritis might have downplayed their discomfort during their visits, either because they self-managed the pain using over-the-counter medications, or it never reached a severity that they felt like they needed to bring it up.

Even with these limitations, having a database with millions of inputs provided some clarity to the research.

“Our thought was that if it is a true phenomenon, even with such a large dataset we would be able to see even a small increase,” Jena said. “The fact that we didn’t see that suggests that this might not be what we think it to be.”

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Still, Jena said there still might be something to the connection between joint pain and different weather events, like a change in barometric pressure or extreme temperatures.

“There could be a true relationship when you look at something like temperature or extreme temperature,” Jena said. “It wouldn’t be too surprising if you see something like joints being more stiff.”

In 2012, researchers in Madrid studied the connection between temperature and pain in patients with rheumatoid arthritis. Patients between 50 and 65 years old were found to be 16 percent more likely to have flare ups in lower average temperatures.

Moving forward, Jena said that he might look at lab data from a major hospital regarding inflammation in the body, which can cause pain and stiffness.

Jena said: “The idea is that if there really is an increase of inflammation on these rainy days, we should be able to see it in lab data.”

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