The rate of diabetes in the US varies widely state to state, as does the rate of diagnosis, depending in part on which state a person lives in, race, and whether the person has insurance, research shows. The study, Diabetes prevalence and diagnosis in US states: analysis of health surveys, is the first study to examine the prevalence of diabetes and the proportion of undiagnosed diabetes state by state. The work was done in collaboration with scientists at the Harvard School of Public Health.
The prevalence of diabetes among US adults was 13.7% among men and 11.7% among women 30 years or older. Researchers found that men in every state were more likely to have diabetes than women. Nationally, approximately 32% of all diabetes cases between 2003 and 2006 were undiagnosed.
Diabetes prevalence was highest in the Southern and Appalachian states: Mississippi, West Virginia, Louisiana, Texas, South Carolina, Alabama, and Georgia (12% to 17%). Vermont, Minnesota, Montana, and Colorado had the lowest prevalence (7% to 12%). The prevalence of undiagnosed cases of diabetes also varied by state. The proportion of undiagnosed diabetes was highest in New Mexico, Texas, Florida, and California and lowest in Montana, Oklahoma, Oregon, Alaska, Vermont, Utah, Washington, and Hawaii.
Researchers also found that among those with no established diabetes diagnosis, being obese, being Hispanic, not having insurance, and being age 60 or older were significantly associated with a higher risk of having undiagnosed diabetes.
Researchers used data from the National Health and Nutrition Examination Survey (NHANES), 2003-2006 to characterize undiagnosed diabetes status as a function of a set of health system and sociodemographic variables using a logistic regression. They applied this relationship to identical variables from the Behavioral Risk Factor Surveillance System (BRFSS) from 2003 to 2007 to estimate state-level prevalence of undiagnosed diabetes by age group and sex. It was assumed that those who reported being diagnosed with diabetes in both surveys were truly diabetic.
Current US surveillance data provide estimates of diabetes using laboratory tests at the national level as well as self-reported data at the state level. Self-reported diabetes prevalence may be biased because respondents may not be aware of their risk status. By estimating the prevalence of diagnosed and undiagnosed diabetes by state, IHME aimed to examine health disparities and provide state and local policymakers with a more accurate picture of health trends at the state level.
Recommendations for future work
This study was unable to include factors that affect diabetes such as diet, quality of care, family history of diabetes, physical activity, alcohol use, and specific dietary risk factors because the BRFSS does not include a detailed dietary questionnaire or family history. A measured blood glucose test for a random sample or for interviewees would provide a validation component to the BRFSS, thus reducing uncertainty in the analysis.
States with high diabetes prevalence should increase the coverage of physical activity and pharmacological interventions for diabetes. Early diagnoses, especially among men, should be a priority in some states to reduce the incidence of complications. States with the highest estimated diabetes prevalence in our analysis also had the highest levels of blood pressure and cardiovascular disease risk, highlighting the need for lifestyle and health care interventions that reduce blood pressure and other cardiovascular risks in high-diabetes states.
Danaei G, Friedman AB, Oza S, Murray CJL, Ezzati M. Diabetes prevalence and diagnosis in US states: analysis of health surveys. Population Health Metrics. 2009 Sep 25; 7:16.