How is osteoarthritis caused? (1) Obesity is an important factor Epidemiological studies have found that obesity can induce osteoarthritis of the knee. The stress and direction of the knee joint depends on the force line of the limb, body shape, muscle strength and their interactions. The incidence of knee osteoarthritis is four times higher in obese individuals, especially women, than in normal weight women. In addition, the distribution of fat in obesity is correlated with the occurrence of osteoarthritis, that is, patients with more fat in the waist are prone to hip and knee osteoarthritis, while fat in the hip and thigh rarely causes osteoarthritis. (2) long-term joint weight damage Many elderly people like to climb two or three times a week, or climb up and down the stairs three times a day, squatting for 10 minutes, jogging for half an hour and other sports, in fact, these exercises, if excessive, is very damaging to the joints. For example, when climbing stairs, the joints must bear three to four times their body weight, which will aggravate the burden and damage to the knee joint, the curvature of the knee joint increases, the pressure between the patella and the femur increases accordingly, and along with the increased wear and tear between the bone and the bone, resulting in pain in the knee joint. (3) Loss of collagen components As we age, degenerative changes occur in the knee joint. We all know that collagen occupies a large portion of both bone and joint, with collagen accounting for 1/3 of the bone and 59% of the joint cartilage. After the age of 35, people gradually lose collagen and calcium, which can easily cause osteoarthritis, osteoporosis and other bone and joint diseases.