The exact cause of arthritis is unknown but is generally believed to be due to wear and tear or overuse.

Research by Rolf Peterson looking at the bones of the moose of Lake Superior has shown that many suffer with arthritis. One might automatically presume that this is due to excess running or a particularly harsh environment involving excess joint loading.
As it turns out, the mouse has developed arthritis due to poor nutrition in early life. This is according to a 50-year research project performed on the moose. This could indicate a potential link between nutritional deficiencies in the womb or throughout childhood and later development of arthritis.

Obesity has also been linked to arthritis. There is a general presumption that this increase in arthritis is due to the additional load applied to the joints. More recent research has suggested that part of the link between obesity and arthritis may be explained by the inflammatory nature of the diet consumed by overweight individuals. Obese individuals may also experience a change in hormone profile which may predispose to joint degeneration

Dr. Peter Bales, an orthopaedic surgeon from the University of California has said that the causes were not as “simplistic” as “carrying more weight around”, but might involve nutritional imbalances that could damage joints and erode cartilage.