Why are these important health dimensions trending toward worse health? The causes are surely complex, but one finding stands out: regardless of whether we studied disability or pain, and regardless of population groups, the key correlate of the increasing trend was the decreasing real income of US families. This finding is critical because is points to the social roots of disability and pain, respectively.
Moreover, a project currently under review led by my student Anthony Jehn at University of Western Ontario is finding comparable increases in disability among Canadian adults. Unlike in the US, however, family income does not appear to be the driving force of the increases – perhaps highlighting the different social-welfare regimes and their impact on population health changes?