A disproportionate number of U.S. adults with arthritis are obese, and the prevalence has been growing over the years, according to a report from the Centers for Disease Control and Prevention.
Obesity and arthritis have a complex relationship, the authors note. "Obesity is an independent risk factor for severe pain, reduced physical function, and disability among adults with arthritis, which might be related to both the increased mechanical stress caused by extra weight on the joints as well as inflammatory effects of elevated cytokines and adipokines that affect cartilage degradation," according to the report.
On average, the obesity prevalence was 54% higher in adults with arthritis than in those without the condition (MMWR 2011;60:509-13).
"Efforts are needed to increase access to and availability of effective services and programs to manage both chronic conditions," the authors wrote.
The report shows that the prevalence of obesity varied widely by state, and 14 states had a significance increase between 2003 and 2009.
There are several reasons for variations among the states, among which is the variation resulting from the underlying obesity rate in the general population of the state, Jennifer M. Hootman, Ph.D., the lead author of the study and an epidemiologist in the arthritis program at the CDC, said in an interview. "States with relatively higher rates of obesity overall tended to also be the higher states among adults with arthritis," she added.
In 2003, the age-adjusted obesity prevalence in adults with arthritis was greater than or equal to 30% in 37 states and the District of Columbia. Two states had a prevalence of 40% or higher.
Fast-forward to 2009, and the number of states with at least 30% of their arthritic population in the obese bracket had increased to 48, 12 of which had a prevalence of 40% or more. During the same year, the obesity prevalence among U.S. adults without arthritis was 30% or higher in only two states.
From 2003 to 2009, the percent change of the prevalence ranged from 26.2% in Wisconsin, to –19.2% in the District of Columbia, the only area with a sharp decline, and it stayed roughly the same in 35 states.
In 2009, nearly 50 million – or 22% – of U.S. adults had arthritis, with an estimated annual medical cost of $128 billion.
Studies have shown that small amounts of weight loss can improve symptoms and function, and can cut the risk of early mortality almost in half (Clin. Geriatr. Med. 2010;26:461-77; J. Gerontol. A Biol. Sci. Med. Sci. 2010;65:519-25).
Other studies have shown that counseling patients with arthritis who are obese has a strong correlation with their attempt to lose weight (Am. J. Prev. Med. 2004;27:16-21).
"However, provider counseling for weight loss and physical activity for adults with arthritis is below the Healthy People 2010 target, and represents an effective but underused opportunity to improve the health of adults with arthritis," said the authors (Ann. Fam. Med. 2011;9:136-41).
Dr. Larry Greenbaum
Reflecting on the trends in his practice, Dr. Larry Greenbaum, a rheumatologist in Greenwood, Ind., said that the report’s findings "do have a ring of truth to them." He said that he recommends diet and exercise to his patients, although "it is very difficult to get people to modify their lifestyle." He added that the 15-minute office visits don’t leave much time for him to delve into counseling, "but I do think it’s important."
Dr. Hootman also stressed the importance of counseling patients to lose weight. "People with arthritis and their health care providers should be encouraged to know that even small amounts of weight loss and small increases in physical activity can have important benefits in terms of reducing pain and improving function," she said.
The study has several limitations. Because the data are self-reported, they’re subject to recall bias; the survey does not include individuals in institutions or households without a landline phone; and the case-finding question in the analysis covered a range of conditions, such as rheumatoid arthritis and gout, which might have different relationships to obesity, according to the authors.
The report is based on the annual Behavioral Risk Factor Surveillance System random-digital-dialed phone survey of adults aged 18 or older in 50 states, the District of Columbia, Guam, Puerto Rico, and the U.S. Virgin Islands. The arthritis and obesity prevalence data are collected in odd-numbered years.
Dr. Greenbaum reported that he has no relevant conflicts of interest.