Obesity and Osteoarthritis Fact Sheet

Osteoarthritis (OA) is strongly associated with weight and obesity.

• OA is a chronic progressive joint disease caused by increased force across the joint and other pro-inflammatory factors such as inflammation throughout the body which is linked to obesity.
• A person with obesity is 60 percent more likely to develop arthritis than someone of normal body weight.
• Joint pain symptoms and severity increase with body mass index (BMI) values. For every 11 pounds of weight gain, there is a 36 percent increased risk for developing OA.
• Women with obesity have nearly four times the risk of knee OA, and men with obesity have five times the risk of knee OA compared to leaner individuals.
• The number of osteoarthritis cases involving the knee in the U.S. could be cut in half if obesity was removed as a risk factor.

Osteoarthritis is not just a wear and tear disease; obesity can be a cause of chronic inflammation throughout the body that can contribute to the development of osteoarthritis.

• Osteoarthritis affects non-weight bearing joints, including joints in the hands, upper extremities, mid-back and neck.
• Obesity is a cause of low-level inflammation in the body.
  • As individuals become affected by obesity and their fat cells enlarge, fat tissue undergoes biological changes affecting metabolism through inflammation.
  • Individuals affected by obesity have higher concentrations of biochemical inflammatory processes and reactions, therefore may be at greater risk for functional limitations and OA disease progressions.
• Fat tissue inflammation is important in the development of obesity-related complications.

The risk of disability in people with OA increases with the degree of obesity.

• Those affected by obesity are 1.72 times more likely to be disabled from OA than normal weight counterparts.
• Those with severe obesity (more than 100 pounds overweight), increase the risk of disability from OA to 2.75 times higher than normal weight persons.
• Force across the knee joint is 3 times one’s body weight while walking, six times one’s body weight while stair climbing and 10 times one’s body weight while jumping.

Weight-loss can reduce joint pain and symptoms of osteoarthritis; obesity is the most modifiable risk factor for OA.

• For women with obesity, for every 11 pounds of weight lost, the risk of knee osteoarthritis drops more than 50 percent.
• Weight-loss can significantly improve the symptoms of patients with osteoarthritis by restoring function and quality of life and preventing more than 100,000 total knee replacements each year.
• Intensive weight-loss will reduce inflammation and joint loads sufficiently to alter disease progression.
• Both exercise training and weight-loss decrease overall inflammation.
• Weight-loss helps prevent the onset of OA symptoms and disability.
  • Obesity (BMI ≥ 30.0 kg/m2) is associated with increased risk of functional impairment and is considered the most modifiable risk factor for knee OA.

Please note: While BMI is commonly used to screen for obesity, it has its limitations and does not replace clinical judgment. BMI is not a direct measure of body fat and does not consider muscle mass, bone mass or fat distribution. Social determinants, race, ethnicity and age may modify the risk associated with a given BMI. An elevated BMI increases your risk for overweight and obesity, but only a healthcare provider can make the final determination.