It always seems to be a lunch lady. She’s got a bum elbow, and whenever the air pressure drops she knows there’s a storm a-brewin'. If the latest research from Australia has anything to say, however, the tall tale of the lunch lady may be little more than a farfetched yarn. The weather may affect your immune system, but it won’t change your chronic pain.
Pain And Weather Records
The study comes from the University of Sydney, where researchers at the George Institute for Global Health wanted to take a new approach to chronic pain study. Much of the research involving weather and pain sensations makes the mistake of trusting patient recall. People aren’t reliable measures when it comes to whether it was sunny and clear or gray and humid, the team explains, so in order to offer practical solutions for lower back pain, the most common musculoskeletal injury on earth, they needed to find the data themselves.
"Many patients believe that weather impacts their pain symptoms," explained lead author, Dr. Daniel Steffens in a statement. But really, what they may feel is the confirmation bias at work — people believe a fact is true, based off experience or speculation, then develop expectations that fulfill the belief if the situation arises. In these cases, reported pain is taking place in the brain; nothing is going on in the nerves themselves.
For their data, Steffens and his team relied on 993 patient cases taken between October 2011 and November 2012. They used weather data from the Australian Bureau of Meteorology, tracked over the same period to crosscheck patients’ reported pain with the relative humidity, temperature, air pressure, wind direction, and precipitation at the time. They used buffer zones of one week and one month prior to reported lower back pain as the experimental and control conditions.
The results are sure to leave lunch ladies everywhere shaking their heads. The only weather condition that came close to producing a greater likelihood for pain was wind speed. But the effect was so small, the researchers discarded it as insignificant. "Our findings refute previously held beliefs that certain common weather conditions increase risk of lower back pain," Steffens concluded. He did concede, however, that symptoms related to specific diseases, such as osteoarthritis and fibromyalgia, warranted further study.
Data, Not Anecdotes
The study’s findings may feel like a violation of something we already know for sure. It’s conventional wisdom that cold or humidity can exacerbate joint pain. The logic makes some sense. People with bad elbows or knees should expect changes in air pressure, low-pressure systems in particular, to produce swelling. After all, the pressure pushing back on a swollen joint would drop.
But the science doesn’t uphold this cultural truth; the plural of anecdote isn’t data. While it’s tempting to agree in passing with people claiming to forecast the weather, judging cause and effect is slippery. It’s made even more slippery when researchers rely on error-prone humans to give accurate accounts of their experiences. Blind observation (blind to the data and also to the reason for study) is the most reliable way to draw conclusions about why and how things work.
As Steffens explains, other diseases may produce different effects. Our friend the lunch lady may be telling the truth; her pain could be localized and neurological. But until science answers those greater questions, many of the answers remain as mysterious as the meat she serves.
Source: Steffens D, Maher C, Li Q, et al. Weather Does Not Affect Back Pain: Results from a Case-Crossover Study. Arthritis Care and Research. 2014.