There's no correlation between achy joints and rainy weather, a study has found, debunking the belief endured over the centuries.
Researchers from the Harvard Medical School in the US used a "big data" approach, linking insurance claims from millions of doctors visits with daily rainfall totals from thousands of National Oceanic and Atmospheric Administration weather stations.
The study, published in the journal BMJ, examined 11 million visits to doctors between 2008 and 2012.
The research team asked a variety of questions: Did more patients seek care for back pain or joint pain when it rained or following periods of rainy weather?
Were patients who went to the doctor for other reasons more likely to also report aching knees or backs around rainy days? What if there were several rainy days in a row? Even in the absence of a "rain effect" in the overall group, did patients with a prior diagnosis of rheumatoid arthritis report more pain?
The answers to all of these questions showed no meaningful link between joint pain and rainy weather.
Overall, 6.35 per cent of the doctor visits included reports of pain on rainy days, compared with 6.39 per cent on dry days.
"We did not see any correlation between rainfall and physician visits for joint pain or back pain," said Anupam Jena, from the Harvard Medical School.