A report from the Centers for Disease Control and Prevention, or CDC, in Atlanta raises concerns about the nation’s obesity crisis: As obesity rates climb, so, too, does the number of people dealing with both obesity and arthritis. And the rates are increasing far faster in some states.

The news is published in the April 29, 2011, edition of Morbidity and Mortality Weekly Report, a weekly public health publication from the CDC. The findings were released in conjunction with the Arthritis Foundation and the beginning of National Arthritis Awareness Month in May.

“As obesity climbs, that’s going to result in more cases of arthritis,” says study co-author Jennifer Hootman, PhD, an epidemiologist with the Arthritis Program at the CDC. “More obesity is eventually going to result in more arthritis cases, we just can’t measure the number right now.”

Researchers at the agency analyzed data from the CDC’s Behavioral Risk Factor Surveillance System, or BRFSS, an ongoing telephone health survey system that has been tracking health-related conditions and behaviors for more than 15 years. During the period examined for this report – 2003 to 2009 – obesity rates rose 2.2 percent among adults without arthritis, from 21.4 to 23.6 percent of Americans. Obesity rates climbed 2 percent among adults with arthritis, from 33.2 to 35.2 percent.

But the most alarming number, say researchers, comes when you compare these two populations: During the years studied, adults with arthritis had an average rate of obesity that was 54 percent higher than obese adults without the condition.

“That’s even adjusting for age. It’s not just that people are aging,” says Hootman. While obesity is on the rise overall, due to such factors as sedentary lifestyles and jobs, an aging population and changes in eating habits, Hootman is troubled to see rising numbers of adults dealing with obesity and arthritis. “If we don’t address obesity in them, we’re likely not going to be able to reach the national goal [of reducing obesity],” she says.

Some States Gain, Others Lose

Researchers also broke down the data state-by-state.

The 10 states with the highest rates of obesity among adults with arthritis – without adjusting for age – are South Carolina (38.7 percent), Arkansas (38.9 percent), Kentucky (38.9 percent), Alaska (39 percent), Michigan (39.3 percent), Missouri (39.7 percent), West Virginia (40.2 percent), Wisconsin (41.5 percent), Mississippi (42.4 percent) and Louisiana (43.5 percent).

The 10 states with the lowest rates of obesity among adults with arthritis – also without age adjustments – are Colorado (26.9 percent), Hawaii (27.8 percent), Vermont (29.5 percent), District of Columbia (29.7 percent), Wyoming (30.6 percent), Arizona (30.7 percent), Rhode Island (30.7 percent), Massachusetts (30.8 percent), Connecticut (30.9 percent) and Oregon (31 percent).

The District of Columbia was the only area studied to show a significant decrease in obesity among adults with arthritis, but Hootman says, “it’s probably not truly that the rate of obesity dropped.” Rather, she suspects it is likely due to the population and demographic shifts the nation’s capital has seen in recent years. “People at lower risk for obesity, like whites and younger males, are moving into D.C.”

Hootman says rates of obesity higher than 30 percent for people with arthritis raise a major concern, and noted that the states that have lower percentages tended to have more of a year-round outdoor activities culture.

“The good news is that we know increasing physical activity is safe for people with arthritis and it can help them lose weight,” says Hootman, who noted the CDC recommends six programs for people with arthritis. The Arthritis Foundation runs three of the programs.

Chicken or Egg?

The BRFSS collects self-reported information that can reveal correlations, but it is not designed to identify causal relationships – such as whether obesity is leading to arthritis or the other way around. It is a topic currently being explored by the scientific community.

“We do know from other studies that obesity increases the risk for particularly osteoarthritis,” Hootman says. But she also acknowledges the role arthritis can play in developing obesity. “Obesity and pain make a big circle, one of those cycles that’s hard to break. It’s harder to move, so you don’t expend calories,” says Hootman.

Stephen Messier, PhD, professor and director of the J.B Snow Biomechanics Laboratory at Wake Forest University in Winston-Salem, N.C., feels more certain that the increased rates of obesity are driving the increased rates of arthritis. “Obesity is the most modifiable risk factor for arthritis,” he says.

This can occur in two ways, Messier explains. One is the added pressure on the knee from weight. The other is inflammation caused from excess fat, as inflammation can degrade knee cartilage. “The good news to that is every pound that you lose, you lose up to 4 pounds of stress off your knee,” he says.

Rising obesity rates among younger adults can mean earlier onset of osteoarthritis, or OA, Messier says. As a result, he foresees an increase in the number of people needing knee replacements earlier in life, and possibly multiple joint replacements during their lifetimes and the increased risks of complications they can come with.

While patients are ultimately responsible for taking control of their diet and exercise – and, by extension, their joints – Messier would like to see the health system offer more support in these areas. “The ideal would be if after seeing a physician who advised you to lose weight, you would then work with the physician’s assistant who has a list of places in town with programs to help,” he says. “In order for this to work on a large scale there’s got to be some sense of connection with the patient over a long period of time, you can’t just tell the patient to lose weight and then don’t give them any direction after that.”