Rain and Pain Not Related, Harvard Researchers Say

Think rain and pain are related? Data tells a different story. Examining insurance claims from millions of doctors' visits with daily rainfall totals from thousands of National Oceanic and Atmospheric Administration weather stations showed that there is no relationship between rainy weather and joint pain or an achy back, according to new research from Harvard Medical School.

Writing in the Christmas issue of the BMJ, the researchers said it is possible a relationship may still exist and that a larger, more detailed study would be needed before this commonly held belief could finally be laid to rest.

"No matter how we looked at the data, we didn't see any correlation between rainfall and physician visits for joint pain or back pain," Anupam Jena, MD, PhD, the Ruth L. Newhouse associate professor of Health Care Policy at Harvard Medical School and an internist at Massachusetts General Hospital, said in a statement. "The bottom line is: painful joints and sore backs may very well be unreliable forecasters."

The study examined Medicare records of more than 11 million primary care office visits by older Americans between 2008 and 2012. Of those visits, 18% occurred on rainy days.

The research team asked:

• 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.

Researchers took into account factors such as patient age, sex, ethnicity, and chronic conditions (including rheumatoid arthritis). However, hey found the proportion of joint or back pain related visits was not associated with rainfall on the day of the appointment or with the amount of rains during that week or the week prior.

Overall, 6.35% of the office visits included reports of pain on rainy days, compared with 6.39% on dry days.

There were no differences in the relation between rainfall and joint or back pain between geographic regions, age groups, or patients with and without rheumatoid arthritis.

This is an observational study, so no firm conclusions can be drawn about cause and effect. Study limitations included a lack of information on disease severity and use of over-the-counter painkillers, which would not be detectable in the data, and which could have influenced the results.

Reference

Jena, A, Olenski, AR, Molitor D, Miller, N. Association between rainfall and diagnoses of joint or back pain: retrospective claims analysis. [published online December 13, 2017]. BMJ. doi/10.1136/bmj.j5326.