Elephants live long lives, generally over 40 years. From an evolutionary standpoint, an animal that large should not develop degenerative changes that threaten its longevity. Yet, they can, in fact, develop arthritis. Elephants in captivity, who are less active than those in the wild, tend to be overweight and have been known to develop arthritis painful enough to require medications and activity modification.
In humans, doctors have long known that increased weight is associated with increased joint pain and arthritis. It stands to reason: Your body is a system of levers in which the mechanical advantage of muscles allows you to accomplish feats of incredible strength. Just look at your average football player. However, when you add even 10 pounds, those muscles have to work harder to move the additional weight around, leading to increased force on the joint cartilage... and more pain. Similarly, if you lose weight, the force on the joint cartilage is diminished, leading to less pain.
Recent research suggests that mechanical forces aren't all that is increased in obesity. Obese patients have increased levels of leptin, a hormone that regulates appetite, and whose excess negatively influences cartilage integrity. So, the issue is not as simple as increased pressure, not to mention all the other effects that obesity has on health: cardiac disease, peripheral vascular disease, diabetes, high blood pressure and stroke, to name just a few.
Losing weight is no laughing matter. There are many programs to help lose weight. There are many gimmick diets, too. Even surgical corrections will fail if you don't do one basic thing: Commit to a lifestyle change. The two key pillars of weight loss -- sustained weight loss -- are consume fewer calories and burn more calories. That means push yourself away from the table before seconds arrive and get off the couch before sleep arrives. Most of my patients who receive a hip and/or knee replacement are overweight to some degree (more than 30 percent of Americans are now classified as obese -- not just overweight). I always advise weight loss before resorting to surgery. In many cases, patients will lose 10-15 pounds, which is enough to see an improvement in pain, and encourage them to keep it up... and off. Sometimes, they even cancel their surgery. If that continues, I could be put out of business! It would be worth it though, to see a healthier America.
I wonder if elephants need joint replacements.