Joint Pain is Strongly Associated with Body Weight
Being only 10 pounds overweight increases the force on the knee by 30-60 pounds with each step.
Osteoarthritis is the most common joint disorder with symptoms in the hands, knees, hips, back, and neck. It is unclear exactly how excess weight influences OA. Clearly, being overweight increases the load placed on the joints such as the knee, which increases stress and could possibly hasten the breakdown of cartilage.(ref. 1) For example, it is estimated that a force of nearly three to six times one’s body weight is exerted across the knee while walking; an increase in body weight increases the force by this amount.(ref. 2) However, overweight has also been associated with higher rates of hand OA in some studies (refs. 3 and 4) suggesting the involvement of a circulating systemic factor as well.(ref. 5)
Obesity Is a Risk Factor for Osteoarthritis
Overweight women have nearly 4 times the risk of knee OA; for overweight men the risk is 5 times greater.
Being overweight is a clear risk factor for developing OA. Population-based studies have consistently shown a link between overweight or obesity and knee OA. Estimating prevalence across populations is difficult since definitions for obesity and knee OA vary among investigators. Data from the first National Health and Nutrition Examination Survey (HANES I) indicated that obese women had nearly 4 times the risk of knee OA as compared with non-obese women; for obese men, the risk was nearly 5 times greater. (ref. 6) In a study from Framingham MA, overweight individuals in their thirties who did not have knee OA were at greater risk of later developing the disease. (ref. 7) Other investigations, which performed repeated x-rays over time also, have found that being overweight significantly increases the risk of developing knee OA. (refs. 8 and 9) It is estimated that persons in the highest quintile of body weight have up to 10 times the risk of knee OA than those in the lowest quintile. (ref. 5)