I enjoyed Nathan Seppa’s article “Cartilage creation,” (SN: 8/11/12, p. 22) about attempts to generate new cartilage from somatic stem cells. He writes that cartilage evolved “in ancestors who lived shorter lives, carried less body weight and roamed an unpaved world.” Implications: The risk of osteoarthritis increases with age, body weight and impact on concrete, such as a long-term runner might experience. Is there solid scientific experience for all three of these putative risk factors?
William Check, San Francisco, Calif.
Yes. First, osteoarthritis stemming from cartilage wear and tear is most common in the elderly. Second, studies show that extra pounds add to stress on weight-bearing joints, particularly the knees. Third, it’s certain that modern humans spend a lot of time in a paved world. Joint compre