Everyone has a story about their back pain and one story you often hear is that the weather makes the person’s back pain worse. Topical now in Sydney as it is quite cold. We had an open mind on the issue because we had heard the story so many times but we also know that as a research question it was wide open as no-one had rigorously evaluated this belief.
We had just finished a case-crossover study investigating whether exposure to factors such as being fatigued/tired or distracted during an activity or task increased the risk of an episode of sudden onset, acute low back pain. We had devoted quite a bit of time and resources to this study as we needed to recruit 1,000 patients from primary care. We then had to promptly interview them about what they were doing for the four days preceding the onset of the acute low back pain. It was a huge undertaking.
After we finished that study we realised that we were in a perfect position to evaluate the story about weather influencing back pain as we could link our back pain data to weather data from the Bureau of Meteorology. Because we conceived the weather study after the first study the weather and back pain data were independent and participants and staff were blinded to the study hypotheses during data collection.
So our data would be unbiased by preconceptions about the influence of weather on back pain. And because data collection took 14 months we had data for weather experienced across four seasons in Sydney.
So what did we do? We used a case-crossover analysis to compare the weather at the time patients first noticed back pain (case window) with weather conditions one week and one month before the onset of pain (control windows). Results showed no association between back pain and temperature, humidity, air pressure, wind direction or precipitation. However, higher wind speed and wind gusts did slightly increase the chances of lower back pain, but the amount of increase was not clinically important. If you are interested the full citation to the article is below.
Subsequent to publishing the paper there has been huge media interest. We had expected some interest but not this much. Along with the media interest there have been lots of people with back pain saying we got it wrong (and mostly in more colourful language than this!).
Have we got it wrong? Well our results came from temperate Sydney and perhaps things are different in other parts of the world with more cold/wet weather. We also only looked at a new episode of back pain and again perhaps things are different for conditions such as long term back pain, fibromyalgia, rheumatoid arthritis, and osteoarthritis. Our results also describe what happens typically and it does not preclude the possibility that there are outliers whose experiences may be different to the average. But as I noted earlier there are lots of things about the study that suggests we probably haven’t got it wrong. It is the context that is key here.
Why would people have such strong views about the weather and their back pain? Well they are no different to the rest of us. We are all fallible and tend to pay more attention to information that confirms our view of the world than information that challenges it. I suspect that people may preferentially recall the occasions when their new episode of back pain lined up with poor weather and tend to forget the other times when this was not the case. This trait of humans is particularly a problem for scientists who have to work really hard to make sure that we base our opinions on a balanced overview of all the research in an area. Scientists were notoriously bad at this and that was one of the reasons why systematic reviews have been promoted in contrast to the earlier (biased) narrative reviews.
About Chris Maher
Chris is Professor of Physiotherapy in Sydney Medical School, The University of Sydney and Director of the Musculoskeletal Division at The George Institute for Global Health. He leads a research division focusing on the management of musculoskeletal conditions in primary care and community settings. Prof Maher’s research evaluates the primary care management of back pain and he holds an honorary NHMRC Senior Research Fellowship and an ARC Future Fellowship.
Link to Chris’ published research here
Steffens, D., Maher, C., Li, Q., Ferreira, M., Pereira, L., Koes, B., & Latimer, J. (2014). Weather does not affect back pain: Results from a case-crossover study Arthritis Care & Research DOI: 10.1002/acr.22378