Increasing Prevalence of Diagnosed Diabetes — United States and Puerto Rico, 1995–2010
In 2010, an estimated 18.8 million persons in the United States had diagnosed diabetes mellitus and another 7.0 million had undiagnosed diabetes (1). Since 1990, the prevalence of diagnosed diabetes in the United States has risen sharply (2,3) among all age groups, both sexes, and all racial/ethnic groups for which data are available (2). To learn whether the increase has been greater in some regions of the United States than in others, data on self-reported diabetes in adults collected during 1995–2010 by the Behavioral Risk Factor Surveillance System (BRFSS) were analyzed. The analysis showed that the age-adjusted prevalence of diagnosed diabetes increased during the interval in every state, the District of Columbia (DC), and Puerto Rico. In 1995, age-adjusted prevalence was ≥6% in only three states, DC, and Puerto Rico, but by 2010 it was ≥6% in every state, DC, and Puerto Rico, and ≥10.0% in six states and Puerto Rico. Strategies to prevent diabetes and its preventable risk factors are needed, especially for those at highest risk for diabetes, to slow the rise in diabetes prevalence across the United States. Continued surveillance of diabetes prevalence and incidence, its risk factors, and prevention efforts is important to measure progress of prevention efforts.
Trends from 1995–2010 were assessed using BRFSS data. Because of changes to BRFSS methods,* 2011 data were not included. BRFSS, a collaborative project of CDC and U.S. states and territories, collects information on health behaviors and conditions using state-based, ongoing, random-digit–dialed telephone surveys of noninstitutionalized U.S. civilian adults aged ≥18 years. The annual median response rate during the period studied ranged from 68.4% (1995) to 54.6% (2010). State sample sizes ranged from 1,193 in Montana to 5,107 in Maryland (1995), and from 1,964 in Alaska to 35,109 in Florida (2010). For each year of 1995–2010, the prevalence of diagnosed diabetes was calculated as the percentage of the population answering "yes" to the question, "Have you ever been told by a doctor that you have diabetes?" Women who had been told that they had diabetes only during pregnancy and respondents told they had prediabetes or borderline diabetes were not considered to have diabetes. Sampling weights and statistical software that account for the complex sampling design of BRFSS were used to estimate state prevalence and median prevalence by U.S. Census region.† Estimates were age-adjusted using the 2000 U.S. standard population and trends analyzed by state, territory, and U.S. Census region. State-specific and regional trends in age-adjusted diagnosed diabetes prevalence incorporating all 16 years of BRFSS data were assessed using least squares regression. Linear and quadratic terms for time (year of survey) were included in the models. The p-value for each overall model was <0.001.
During 1995–2010, the age-adjusted prevalence of diagnosed diabetes among U.S. adults increased in all geographic areas, with the median prevalence for all states, DC, and Puerto Rico increasing from 4.5% to 8.2% (Table). In 1995, age-adjusted prevalence was ≥6% in only three states, DC, and Puerto Rico, but, by 2010, it was ≥6% in all areas (Table, Figure 1). In 2010, median age-adjusted prevalence was highest among states in the South (9.8%) versus states in the Midwest (7.5%), Northeast (7.3%), and West (7.3%). In 2010, age-adjusted prevalence was highest (≥10.0%) in Alabama, Mississippi, Puerto Rico, South Carolina, Tennessee, Texas, and West Virginia, and lowest (6.0%–6.9%) in 12 states: Alaska, Colorado, Connecticut, Iowa, Minnesota, Montana, North Dakota, Oregon, South Dakota, Wisconsin, Vermont, and Wyoming.
During 1995–2010, the relative increase in age-adjusted prevalence of diabetes ranged from 8.5% in Puerto Rico to 226.7% in Oklahoma, with an overall median increase of 82.2%. The age-adjusted prevalence increased by ≥50% in 42 states and by ≥100% in 18 states. States in the South had the largest relative increase in prevalence, with the age-adjusted median increasing >100% (Table, Figure 2). The next largest increase was seen in the West, where the median increased 82.5%, followed by a 66.7% increase in the Midwest and a 62.2% increase in the Northeast.