Being overweight increases the wear on your joints, so that the heavier you are, the greater the risk that you will develop severe osteoarthritis. But this only holds true for your knees. Your body mass index (BMI) does not appear to affect the development of osteoarthritis in your hips, according to a study based on data collected from a series of major health surveys conducted in Nord-Trøndelag county.
The study was conducted by researchers at NTNU’s Department of Human Movement Science, and included 30 000 men and women, all of whom had functioning and pain-free hips and knees in the first survey. Ten years later, 351 people reported osteoarthritis of the knee, while 322 reported arthritis in the hips. The incidence of knee arthritis was 3-4 times greater among individuals who were obese (BMI over 30), compared to normal weight individuals. Being overweight (BMI 25-29) was also associated with increased risk. These associations were slightly stronger among women than among men.
The researchers also examined whether hard exercise could be a risk factor for developing osteoarthritis, especially among those who were overweight, but found no such relationship. The researchers say that fear of osteoarthritis should not frighten anyone away from exercising, even people who are obese.