Being overweight, particularly if you have a higher than average body mass index (BMI), may increase your risk for developing severe osteoarthritis in your hips and knees, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in San Francisco, Calif.

Osteoarthritis, or OA as it is commonly called, is the most common joint disease affecting middle-age and older people. It is characterized by progressive damage to the joint cartilage—the slippery material at the end of long bones—and causes changes in the structures around the joint. These changes can include fluid accumulation, bony overgrowth, and loosening and weakness of muscles and tendons, all of which may limit movement and cause pain and swelling.

Swedish researchers recently measured the body mass, waist, waist-to-hip ratio, weight and percentage of body fat of 11,026 male and 16,934 female members from the general population-who ranged in age from 45 to 73 years-and of that group, 1,022 OA patients who had undergone joint replacement surgery were identified 11 years later

Researchers then compared 471 patients who had total knee replacement and 551 patients who had total hip replacement due to OA with those who did not to define the relationships between body mass and knee and hip OA leading to joint replacement. They also explored the relationships between C-reactive protein, metabolic syndrome and the incidence of severe knee and hip OA.

After adjusting for other important risk factors, including age, sex, smoking status, other illnesses, C-reactive protein, and physical activity level, researchers determined that being overweight by any measure identified was associated with knee OA leading to joint replacement. Of all measures, a higher body mass was the biggest risk factor associated with developing severe hip or knee OA for both men and women.

In this study, which is the largest and the first that compares the effect of different measures of body mass on the risk of severe OA over time in the knees and hips of both men and women in the same population, investigators also demonstrated that the risk increase of developing severe OA is more strongly related to increased joint loading due to being overweight than to the metabolic changes associated with being overweight or obese (such as, increased CRP and metabolic syndrome).

"[Being] overweight is one of the few factors leading to osteoarthritis that we can actually do something about," explains Stefan Lohmander, MD, PhD; professor and senior consultant; Lund University, department of orthopaedics, clinical services, Lund, Sweden, and lead investigator in the study. "Understanding the connection between being overweight and getting osteoarthritis, and the size of the risk, is therefore important when considering disease prevention. We have shown that the risk increase starts already with being moderately overweight, and increases with each further increase in body mass. This is true for men and for women, and for knees and for hips."

When considering the impact this may have on patients in the United States, Dr. Lohmander says, "This study was done in Sweden and started more than 10 years ago. The frequency of obesity and its severity was (and is) less severe in Sweden than in the U.S. Had this study been done in the U.S. today, I expect that we would have seen even more dramatic increases in [the] risk of osteoarthritis of the knee and hip due to [being] overweight and obesity. Osteoarthritis should be added to the already long list of diseases increasing steeply due to the obesity epidemic."

About Arthritis

Arthritis (from Greek arthro-, joint + -itis, inflammation; plural: arthritides) is a group of conditions involving damage (inflammation) to the joints of the body. Arthritis is the leading cause of disability in people older than fifty-five years.  A joint is an area of the body where two different bones meet. A joint functions to move the body parts connected by its bones. Arthritis literally means inflammation of one or more joints.

More than 21 million Americans have osteoarthritis. Approximately 2.1 million Americans suffer from rheumatoid arthritis.

More than half of those with arthritis are under 65 years of age. Nearly 60% of Americans with arthritis are women. 

What are the Causes of Arthritis?  The causes of arthritis depend on the form of arthritis. Causes include injury (leading to osteoarthritis), abnormal metabolism (such as gout and pseudogout), inheritance, infections, and unclear reasons (such as rheumatoid arthritis and systemic lupus erythematosus).

Arthritis is classified as one of the rheumatic diseases. These are conditions that are different individual illnesses, with differing features, treatments, complications, and prognosis. They are similar in that they have a tendency to affect the joints, muscles, ligaments, cartilage, tendons, and many have the potential to affect internal body areas.

How is Arthritis Diagnosed?  Only a doctor can diagnose arthritis. An accurate diagnosis is needed so treatment can begin. The first step in the diagnosis of arthritis is a meeting between the doctor and the patient. The doctor will review the history of symptoms, examine the joints for inflammation and deformity, as well as ask questions about or examine other parts of the body for inflammation or signs of diseases that can affect other body areas. Certain blood, urine, joint fluid, and/or x-ray tests might be ordered based on the results of the intial examination.

The Importance of Early Diagnosis  Earlier and accurate diagnosis can help to prevent irreversible damage and disability. Properly guided programs of exercise and rest, medications, physical therapy, and surgery options can maximize long-term outcomes for arthritis patients.

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disorder that causes the immune system to attack the joints and joint destruction. It is diagnosed with causing inflammation (arthritis), and some organs, such as the lungs and skin. It can be a disabling and painful condition, which can lead to substantial loss of functioning mobility due to pain.

The name is based on the term "rheumatic fever", an illness which includes joint pain and is derived from the Greek word rheumatos ("flowing"). The suffix -oid ("resembling") gives the translation as joint inflammation that resembles rheumatic fever. The first recognized description of rheumatoid arthritis was made in 1800 by Dr Augustin Jacob Landré-Beauvais (1772-1840) of Paris.

About Osteoarthritis

Osteoarthritis also known as degenerative arthritis, degenerative joint disease), is a condition in which low-grade inflammation results in pain in the joints, caused by abnormal wearing of the cartilage that covers and acts as a cushion inside joints and destruction or decrease of synovial fluid that lubricates those joints. As the bone surfaces become less well protected by cartilage,  pain is experienced upon weight bearing, including walking and standing. Due to decreased movement because of the pain, regional muscles may atrophy, and  ligaments may become more lax.

"Osteoarthritis" is derived from the Greek word "osteo", meaning "of the bone", "arthro", meaning "joint", and "itis", meaning inflammation, although many sufferers have little or no inflammation. Osteoarthritis affects nearly 21 million people in the United States, accounting for 25% of visits to primary care physicians, and half of all NSAID (Non-Steroidal Anti-Inflammatory Drugs) prescriptions. More than 10 million Americans have a total joint replacement each year.

A common misconception is that osteoarthritis is due solely to wear and tear, due to the fact that osteoarthritis typically is not present in younger people. However, while age is correlated with osteoarthritis incidence, this merely illustrates that osteoarthritis is a process that takes time to develop. There is usually an underlying cause for osteoarthritis, in which case it is described as secondary osteoarthritis. If no underlying cause can be identified it is described as primary osteoarthritis. "Degenerative arthritis", often used as a synonym for osteoarthritis, but the latter involves both degenerative and regenerative changes.

It is estimated that 80% of the population will have radiographic evidence of osteoarthritis by age 65, although only 60% of those will be symptomatic.

Being overweight, particularly if you have a higher than average body mass index, may increase your risk for developing severe osteoarthritis in your hips and knees, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in San Francisco, Calif.

Osteoarthritis, or OA as it is commonly called, is the most common joint disease affecting middle-age and older people. It is characterized by progressive damage to the joint cartilage—the slippery material at the end of long bones—and causes changes in the structures around the joint. These changes can include fluid accumulation, bony overgrowth, and loosening and weakness of muscles and tendons, all of which may limit movement and cause pain and swelling.

About the American College of Rheumatology 

The American College of Rheumatology (ACR) is an organization of and for physicians, health professionals, and scientists that advances rheumatology through programs of education, research, advocacy and practice support that foster excellence in the care of people with or at risk for arthritis and rheumatic and musculoskeletal diseases. For more information on the ACR's annual meeting, see www.rheumatology.org/annual.

Source of Study Information 

Incidence Of Severe Knee And Hip Osteoarthritis In Relation To Different Measures Of Body Mass, Metabolic Syndrome, And CRP. A Population-based Prospective Cohort Study

Stefan Lohmander1, Maria Gerhardsson2, Jan Rollof2, Peter M. Nilsson1, Gunnar Engström2. 1Lund University, Lund, Sweden; 2AstraZeneca R&D, Lund, Sweden