Ecology of arthritis.

Osteoarthritis (OA) is a widespread degenerative disease of skeletal joints and is often associated with senescence in vertebrates. OA commonly results from excessive or abnormal mechanical loading of weight-bearing joints ('wear-and-tear'), arising from heavy long-term use or specific injuries; yet, in the absence of injury, the aetiology of OA remains obscure. We show that poor nutritional conditions experienced by moose (Alces alces) early in life are linked to greater prevalence of OA during senescence as well as reduced life expectancy. Moreover, we also found a negative relationship between kill rate by wolves (Canis lupus) and prevalence of OA, suggesting a potential connection between senescence of prey and the population ecology of predator-prey systems. This association between OA and early malnutrition also provides a basis for explaining the observation in anthropology that OA became more prevalent in native Americans as their diet become poorer - the result of relying more on corn and agriculture and less on hunting and gathering.