Arthritis rates underestimated and driven by obesity

Millions more Americans are suffering from arthritis than their doctors realize, a new study reports.

Affecting more than one third of adults, rates of arthritis have even outpaced the obesity epidemic, which may in part be fueling the surge in arthritis symptoms.

Depending on age and gender, between 13 and 20 percent of adults report symptoms of arthritis, but have never been diagnosed by their doctors, according to the new study from Boston University.

The study found that arthritis was 68 percent more common than previous estimates, suggesting that evaluations for the condition may be insufficient. 

Arthritis, which causes inflammation of the joints, may be as much as 68 percent more common than previous estimates have suggested, a new study found

Arthritis, in its various forms, most commonly affects adults 65 and older, but can strike anyone. 

Doctors diagnose arthritis by assessing joints for swelling, redness and warmth to the touch. They also may examine joints for range of motion, and how painful movement is. 

Tests of blood, urine and spinal fluid, accompanied by images of the joints can confirm a diagnosis, but, the new study’s findings suggest, many patients may not even get to this stage. 

The most common form, osteoarthritis (OA), usually develops slowly over a lifetime, as use wears down the cartilage that coats the ends of bones to keep them from grinding painfully against one another. 

Both it and the disease’s autoimmune form, rheumatoid arthritis (RA), cause joint inflammation that can limit mobility and dexterity. 

Injuries, age, infections, being a woman and family history all make us increasingly prone to arthritis, and are out of our control. 

But obesity is a significant risk factor, and the rise of arthritis runs tandem to the obesity epidemic in the US. 

‘Studies have reported a rising rate of surgeries such as total knee replacement that outpaced obesity rates in recent years, especially among younger adults affected by arthritis,’ said study co-author Dr S Reza Jafarzadeh. 

Between 2012 and 2015, there has been a more than 100 percent increase in joint replacement surgeries, according to data from the American Joint Replacement Registry.  

Every pound of body weight exerts an additional four pounds of pressure on the knees, according to the Arthritis Foundation. 

The extra force, unsurprisingly, accelerates the process of wear and tear on the joints, making arthritis more likely. 

About 36.8 percent of the US population suffers from arthritis, based on the new study’s analysis of 2015 National Institutes of Health data. That’s only 1.1 percent less than the portion of the country that is obese. 

The data suggest that if fewer Americans were obese, fewer would suffer from arthritis, particularly considering that the researchers found that far more adults under 64 are affected by arthritis than previously thought. 

‘Our findings are important because of underestimated, yet enormous, economic and public health impacts of arthritis including healthcare costs and costs from loss of productivity and disability, including in adults younger than 65 years of age,’ said Dr Jafarzadeh.