Overall, one thing you can see if the prevalence seems to decrease a little bit with age so that the peak prevalence of back pain is usually in the 40’s and 50’s. There have been a lot of theories put forward as to why this might be. I’ll talk about those in just a minute. Usually women report a more back pain than do men. A major problem with back pain is there is “no gold standard”. Nobody knows what anybody else is taking about when they say back pain. Or when I say I have back pain that may be very different from what you’re calling back pain. Certainly in the orthopedic literature there have been no studies with the validity/reliability of diagnosis of many orthopedic testing procedure, diagnostic procedures. And there has been very little done in epidemiology looking at the reliability/reducibility of self-reported back pain.