The relative increase in age-adjusted prevalence of diabetes from 1995-2010 ranged from 8.5 percent in Puerto Rico to 226.7 percent in Oklahoma, with an overall median increase of 82.2 percent, according to a Centers for Disease Control and Prevention (CDC) report.

The analysis was published Nov. 16 in the Morbidity and Mortality Weekly Report.

In 2010, an estimated 18.8 million Americans had diagnosed diabetes mellitus and another 7 million had undiagnosed diabetes, according to the CDC. Since 1990, the CDC has reported that the prevalence of diagnosed diabetes in the U.S. has risen sharply among all age groups, both sexes and all racial/ethnic groups.

To learn whether the increase has been greater in some regions of the U.S. than in others, Linda S. Geiss, MA, of the CDC’s diabetes division, analyzed data on self-reported diabetes in adults collected during 1995-2010 by the Behavioral Risk Factor Surveillance System (BRFSS), which is a collaborative project of CDC and U.S. states and territories. The BRFSS collects information on health behaviors and conditions using state-based, ongoing, random-digit–dialed telephone surveys of non-institutional­ized U.S. civilian adults (18 years or older).

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, Washington, D.C., and Puerto Rico increasing from 4.5 percent to 8.2 percent, according to the findings.

In 1995, age-adjusted prevalence was 6 percent or higher in only three states, Washington, D.C., and Puerto Rico, but, by 2010, it was 6 percent or higher in all areas.

In 2010, Geiss et al reported that the median age-adjusted prevalence was highest among states in the South (9.8 percent) versus states in the Midwest (7.5 percent), Northeast (7.3 percent) and West (7.3 percent). In 2010, age-adjusted prevalence was highest (10 percent or higher) in Alabama, Mississippi, Puerto Rico, South Carolina, Tennessee, Texas and West Virginia, and lowest (6-6.9 percent) in 12 states: Alaska, Colorado, Connecticut, Iowa, Minnesota, Montana, North Dakota, Oregon, South Dakota, Wisconsin, Vermont and Wyoming.

The age-adjusted prevalence increased by 50 percent or more in 42 states, and by 100 percent or more in 18 states.

The prevalence “increase is likely the result of improved survival of persons with diabetes and increasing diabetes incidence,” the authors wrote. “Nationally representative data suggest that mortality among U.S. adults with diabetes declined substantially between 1997 and 2006.”

States in the South had the largest relative increase in prevalence, with the age-adjusted median increasing by more than 100 percent, the report found. The next largest increase was seen in the West, where the median increased 82.5 percent, followed by a 66.7 percent increase in the Midwest and a 62.2 percent increase in the Northeast.

The prevalence of diagnosed diabetes is highest in southern and Appalachian states, and it is increasing rapidly in these areas, the researchers found. “This might be because of the greater prevalence of risk factors for diabetes (e.g., obesity and sedentary lifestyle), a larger proportion of African-American ancestry in the popula­tion, and cultural and other factors that contribute to poor nutrition and unhealthy lifestyles,” they wrote.

“Increasing incidence might be the result of many factors, including changes in diagnostic criteria, enhanced detection of undiagnosed diabetes, demographic changes in the U.S. population (e.g., aging of the population and growth of minority populations who are at greater risk for diabetes) and an increase in the prevalence of risk factors for the development of diabetes (e.g., obesity and sedentary lifestyle),” Geiss et al wrote. “Although the contribution of each factor to increasing diabetes incidence cannot be discerned, the increase in diabetes prevalence coincides with the increase in obesity prevalence across the U.S.”

The authors noted that these have implications for public health practices. “Strategies to prevent diabetes and its risk factors, both in the general population and among those at high risk for develop­ing diabetes, are needed to reverse the persistent and ubiqui­tous upward trend of diabetes prevalence in the U.S.,” they concluded.