The metabolic roots of pain

In 2017, Hussain et al. reported evidence of the metabolic roots of back pain, which is probably relevant to other kinds of chronic pain as well.

The majority (82%) of 5000 Australians reported back pain on a questionnaire, and in 27% of them it was bad enough to be disabling. When compared to their fat mass fat distribution — a well-known indicator of metabolic disorders — a clear pattern emerged: back pain intensity and disability go up with measures of fat mass and distribution.

This data challenges that idea that weight is a “mechanical” problem for backs — greater weight causing greater stress on spinal joints — which is an extremely popular assumption. Nearly universal, actually. You’d be hard-pressed to find someone who does not think that extra weight is a physical risk factor for back pain.

What this evidence does suggest is that “systemic metabolic factors associated with adiposity play a major role in the pathogenesis of LBP.” The weight isn’t the problem, but the biochemistry of being out of shape.

This is a particularly fine example of what I mean when I argue that we need to look beyond trivial physical stresses and biomechanical factors to the messy “wet” factors in chronic pain, the things that make us more vulnerable to pain.