Prevalence of Obesity Among Adults with Arthritis --- United States, 2003--2009

Obesity and arthritis are critical public health problems with high prevalences and medical costs. In the United States, an estimated 72.5 million adults aged ≥20 years are obese, and 50 million adults have arthritis. Medical costs are estimated at $147 billion for obesity and $128 billion for arthritis each year (1--3). Obesity is common among persons with arthritis (2) and is a modifiable risk factor associated with progression of arthritis, activity limitation, disability, reduced quality-of-life, total joint replacement, and poor clinical outcomes after joint replacement (4,5). To assess obesity prevalence among adults with doctor-diagnosed arthritis, CDC analyzed data from the Behavioral Risk Factor Surveillance System (BRFSS) for the period 2003--2009. This report summarizes the results of that analysis, which determined that, among adults with arthritis, 1) obesity prevalence, on average, was 54% higher, compared with adults without arthritis, 2) obesity prevalence varied widely by state (2009 range: 26.9% in Colorado to 43.5% in Louisiana), 3) obesity prevalence increased significantly from 2003 to 2009 in 14 states and Puerto Rico and decreased in the District of Columbia (DC), and 4) the number of U.S. states with age-adjusted obesity prevalence ≥30.0% increased from 38 (including DC) in 2003 to 48 in 2009. Through efforts to prevent, screen, and treat obesity in adults, clinicians and public health practitioners can collaborate to reduce the impact of obesity on U.S. adults with arthritis.

BRFSS* is an annual, random-digit--dialed telephone survey of adults aged ≥18 years conducted in all 50 states, DC, Guam, Puerto Rico, and the U.S. Virgin Islands.* Arthritis and obesity prevalence data are collected in odd numbered years. For this analysis, the total survey participants were as follows: 264,864 in 2003; 356,112 in 2005; 430,912 in 2007; and 432,607 in 2009. Data from those 4 years for the 50 states and DC were used to assess median obesity prevalence among adults with and without arthritis and to produce obesity prevalence maps. Data from 2003 and 2009 were used to assess changes in obesity prevalence among adults with arthritis by state/area. For 2003, 2005, 2007, and 2009 respectively, median Council of American Survey and Research Organizations (CASRO) response rates were 53.2%, 51.1%, 50.6%, and 52.5%; median CASRO cooperation rates were 74.8%, 75.1%, 72.1%, and 75.0%, respectively.†

Respondents were defined as having arthritis if they responded "yes" to the question "Have you ever been told by a doctor or other health professional that you have some form of arthritis, rheumatoid arthritis, gout, lupus, or fibromyalgia?" Body mass index (weight [kg] / height [m2]) was calculated from self-reported weight and height. Obesity was defined as a body mass index ≥30.0. Respondents reporting body weight ≥500 pounds or height ≥7 feet or <3 feet were excluded (1). Unadjusted, weighted obesity prevalence and 95% confidence intervals for each state/area were calculated using sampling weights, which take into account the complex sample design, nonresponse, and noncoverage, by state/area; unadjusted estimates were calculated to enable states to use these data in program planning and awareness efforts. Statistical significance of percentage changes in unadjusted obesity prevalence by state/area was determined by t-test (p<0.05). In addition, state-specific obesity prevalence estimates among adults with arthritis were age-adjusted to the 2000 U.S. standard population.§

For each of the 4 years analyzed, unadjusted median obesity prevalence for the 50 states and DC was significantly higher among adults with arthritis than adults without arthritis. On average for the 4 years, unadjusted state median obesity prevalence among adults with arthritis was 54% higher (range: 49.2%--60.5%) than among adults without arthritis (Figure 1).

In 2003, unadjusted median state (including DC) obesity prevalence among adults with arthritis was 33.2%; prevalence ranged from 25.1% in Colorado to 40.1% in Ohio (Table). In 2009, unadjusted median state obesity prevalence among adults with arthritis was 35.2%; prevalence ranged from 26.9% in Colorado to 43.5% in Louisiana. From 2003 to 2009, the percentage change in prevalence ranged from -19.2% in DC to 26.2% in Wisconsin. From 2003 to 2009, unadjusted obesity prevalence among adults with arthritis increased significantly in 14 states and Puerto Rico and decreased significantly in DC (Table).

In 2003, a total of 37 states and DC had an age-adjusted obesity prevalence among adults with arthritis ≥30.0% (including two states with prevalence ≥40.0%) (Figure 2). From 2003 to 2009, the number of states with obesity prevalence ≥30.0% increased each survey year: 42 states in 2005 (zero states ≥40.0%), 45 states and DC in 2007 (seven states >40.0%), and 48 states in 2009 (12 states ≥40.0%) (Figure 2).

Reported by

Jennifer M. Hootman, PhD, Charles G. Helmick, MD, Casey J. Hannan, MPH, Div of Adult and Community Health, Liping Pan, MD, Div of Nutrition, Physical Activity, and Obesity, National Center for Chronic Disease Prevention and Health Promotion, CDC. Corresponding contributor: Jennifer M. Hootman, CDC, 770-488-6038, [email protected].

Editorial Note

The findings in this report indicate that, among adults with arthritis in the United States, obesity prevalence was higher than among adults without arthritis and increased significantly in 15 states/areas from 2003 to 2009. In 2009, age-adjusted obesity prevalence among adults with arthritis was ≥30% in 48 states; obesity prevalance among adults without arthritis was ≥30% in only two states (CDC, unpublished data, 2011).

Because of the complex relationships between obesity, joint pain, function, and physical activity, adults with arthritis have difficulty maintaining and losing weight (4). 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 (4). Obesity also can impair the ability to be physically active, a key self-management and weight loss and maintenance strategy that not only can improve pain and function among adults with arthritis, but also contribute to the energy expenditure needed to lose or maintain weight (4).

Even small amounts of weight loss (e.g., 10--12 pounds) can have important benefits for persons with arthritis (4). Randomized controlled interventions of diet, exercise, and diet plus exercise among overweight and obese adults with osteoarthritis have reduced body weight by approximately 5%, improving symptoms and functioning, and preventing short-term disability (4). Intentional weight loss among obese adults with osteoarthritis might reduce the risk for early mortality by nearly 50% (6). Reducing obesity prevalence to approximately that observed in 2000 in this population might prevent 111,206 total knee replacements and increase life expectancy by an estimated 7.8 million quality-adjusted years (7).

For health-care providers, counseling patients with arthritis to lose weight and be more physically active has been shown to correlate strongly with healthy behaviors such as attempts to lose weight (8). However, provider counseling for weight loss and physical activity for adults with arthritis is below the Healthy People 2010 target (9) and represents an effective but underused opportunity to improve the health of adults with arthritis. Community-based efforts to reduce or maintain weight recommended for adults by the Guide to Community Preventive Services include technology-supported coaching or counseling interventions as well as worksite strategies (e.g., policies to improve access to healthy foods and opportunities to be physically active).¶ U.S. Preventive Services Task Force clinical recommendations include screening and intensive counseling (one or more sessions per month for at least 3 months), plus behavioral interventions for all obese adults.** Creating linkages between the health-care system and community-based obesity prevention and treatment programs is a potential strategy to address obesity among adults with arthritis.

The findings in this report are subject to at least four limitations. First, all BRFSS information is self-reported and subject to recall bias. In a study of 2001--2006 data, weight was found to be underestimated, especially by women, and height was found to be overestimated by both men and women (10), and these tendencies might affect BRFSS results. Second, single-year estimates of obesity prevalence among adults with arthritis for individual states might be imprecise because of small sample sizes that result from year-to-year differences in survey execution, budgetary constraints, and natural disasters. All estimates in this report meet minimum reliability standards (relative standard errors <30.0%); however, some estimates with wide confidence intervals are less precise. Third, BRFSS does not include persons residing in institutions and, during 2003--2009, did not include households without a landline telephone. Finally, the case-finding question in this analysis covers a range of conditions (i.e., some form of arthritis, rheumatoid arthritis, gout, lupus, or fibromyalgia), which might have different relationships to obesity. Because of the survey design, separate analyses by condition type could not be performed.

Approximately 22% of U.S. adults have arthritis (2), and a disproportionate number of those persons are categorized as obese. Efforts are needed to increase access to and availability of effective services and programs to manage both chronic conditions. A broad approach to reducing obesity, as outlined in the Surgeon General's Vision for a Healthy and Fit Nation 2010,†† includes addressing both diet and physical activity, leveraging multiple sectors (e.g., health care, communities, and work sites), and utilizing various strategies (e.g., individual behavior, environment, and policy changes). Such an approach might help adults with both conditions increase healthy behaviors that can lessen the impact of obesity and arthritis and improve their overall quality of life.

References

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