US arthritis numbers much higher than current estimates, new research indicates

27 Nov 2017 --- The prevalence of arthritis in the United States has been substantially underestimated, especially among adults over 65 years old, according to new research. The Arthritis & Rheumatology findings indicate that research is needed to better monitor arthritis prevalence in the US population and to develop better prevention strategies.

The results may be of interest to the nutrition industry, with many different nutritional solutions to arthritis having been proposed in recent months. Maintaining sufficient vitamin D levels may prevent its onset, according to research led by the University of Birmingham in the UK, and algae has been linked to its treatment by a group of researchers at ETH Zurich, Empa and the Norwegian research institute SINTEF. Researchers also found that individuals with rheumatoid arthritis who consumed fish more than twice a week had lower disease activity than those who never ate fish or ate it just once a month.

New method for arthritis surveillance
Current US national estimates of arthritis rely on a single survey question, asking participants whether they remember being ever told by a health professional that they have arthritis, without using information on patients’ joint symptoms that is available in the survey.

As many cases of arthritis may be missed by the current method, S. Reza Jafarzadeh, Ph.D., and David T. Felson, M.D., of Boston University School of Medicine, developed a different method for arthritis surveillance. Their method was based on doctor-diagnosed arthritis, chronic joint symptoms and whether symptom duration exceeded three months.

In their analysis of the 2015 National Health Interview Survey (NHIS), the researchers found that arthritis affects a much higher percentage of the US adult population and at a younger age than previously thought. Of 33,672 participants, 19.3 percent of men and 16.7 percent of women aged 18 to 64 reported joint symptoms without a concurrent report of doctor-diagnosed arthritis. For participants 65 years of age and older, the respective proportions were 15.7 percent and 13.5 percent.

The prevalence of arthritis was 29.9 percent in men aged 18 to 64 years, 31.2 percent in women aged 18 to 64 years, 55.8 percent in men aged 65 years and older and 68.7 percent in women aged 65 years and older. Arthritis affected 91.2 million US adults (36.8 percent of the population) in 2015, which included 61.1 million persons between 18 to 64 years (31.6 percent of the population).

The investigators’ prevalence estimate is 68 percent higher than previously reported arthritis national estimates that did not correct for measurement errors in the current surveillance methods, Wiley reports.

“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,” says Dr. Jafarzadeh. “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.”

Dr. Jafarzadeh further notes that current arthritis surveillance methods, which have been used since 2002, should be revised to correct for inherent limitations of the survey methods and to increase accuracy.

For more information on healthy aging, be sure to check out NutritionInsight’s special report with industry input here.