Background
Diabetes Mellitus is the sixth leading cause of death in the United States (U.S.), accounting for approximately 70,000 annual deaths. Age-standardized adult diabetes death rates across U.S. states ranged from approximately 2 per 10,000 people in Arizona and Florida to 4.5 to 5 in West Virginia and the District of Columbia (D.C.)
Currently, the only source of information on diabetes prevalence at the state level is the Behavioral Risk Factor Surveillance System (BRFSS), a state-representative telephone survey. However, the BRFSS data are based on self-reports and do not provide estimates of undiagnosed diabetes. The National Health and Nutrition Examination Survey (NHANES) uses laboratory measurements and provides estimates of diagnosed and undiagnosed diabetes, but is representative only at the national level. In this study, we combined data from NHANES and BRFSS to estimate diabetes prevalence and diagnosis at the state level. Our results provide information for state diabetes prevention and control programs, and our methods can be used for regular low-cost monitoring of diabetes at the state level.
Methods
Data Sources
NHANES uses a complex multistage stratified clustered probability design to measure health and nutrition characteristics of a nationally representative sample of the civilian non-institutionalized population aged two months and older. NHANES includes an in-person interview and a subsequent physical examination and measurement component in a mobile examination clinic (MEC) or at home for those unable to visit the MEC. We used NHANES data from 2003 to 2006. The response rates for the household interviews were 80% for 2003-2004 and 79% for 2005-2006. The corresponding response rates for the medical examination after the household interview were 95 to 96%.
Each interviewed participant was randomly assigned to either a morning or afternoon/evening MEC session. Subjects ≥ 20 years old assigned to the morning session were asked to fast for 8 to 24 hours, with the exception of those on insulin or those who were excluded for other safety reasons. The NHANES MEC and fasting sample weights account for exclusion, non-response, and inappropriate fasting time. Additional information on NHANES design and methods, including on diabetes measurement, is available elsewhere
The BRFSS is an annual cross-sectional telephone health survey. Currently, the survey is conducted in all 50 states and the District of Columbia using random-digit dialing to obtain a state-representative sample of the civilian, non-institutionalized population aged 18 and over. In 2003, the response rate among eligible subjects who answered the phone was 77%. Additional information on the design is available elsewhere
We included adults aged 30 and older in NHANES and BRFSS who had answered the self-reported diabetes question, which asked if they had ever been told by a health professional that they had diabetes. The response rate for this question was more than 99.8% in both surveys. We did not include younger participants because diabetes prevalence is relatively low in these ages.
Statistical Analysis
Consistent with previous analyses
We used data from NHANES, which is representative at the national but not at the state level, to characterize the relationship between undiagnosed diabetes status (defined as FPG ≥ 126 mg/dL) and a set of health system, sociodemographic, and risk factor variables listed in Table
Description of the outcome and explanatory variables from NHANES and BRFSS and the corresponding odds ratios (OR) and 95% confidence intervals (95% CI).
Variable
Reason for inclusion in analysis
Possible values
OR
(95% CI)
Undiagnosed diabetes (available in NHANES; predicted in BRFSS)
Outcome variable to estimate undiagnosed diabetes
0 (FPG < 126 mg/dL)
1 (FPG ≥ 126 mg/dL)
-
-
Sex
Predictor of diabetes, possibly because of differences in lifestyle and health care determinants
Male
1.0
-
Female
0.47
0.29, 0.77
Age (years)
Predictor of diabetes
30-39
1.0
-
40-49
1.07
0.41, 2.81
50-59
3.25
1.41, 7.50
60-69
7.49
3.55, 15.82
≥ 70
7.02
3.23, 15.26
Race *
Predictor of diabetes and health care access
Non-Hispanic white
1.0
-
Non-Hispanic black
1.11
0.63, 1.96
Hispanic
2.03
1.07, 3.83
Other
0.26
0.03, 1.91
Doctor visit (have you seen a doctor in the past year?) †
Indicator for diabetes knowledge and control
No
0.49
0.23, 1.05
Yes
1.0
-
Insurance status (do you currently have health insurance?)
Indicator for diabetes knowledge and control
No
1.58
0.83, 3.02
Yes
1.0
Missing
0.76
0.07, 8.42
BMI (kg/m2) ‡
Determinant of diabetes and indicator for selected lifestyle factors such as diet and physical activity
< 25
1.0
-
25-29
1.85
0.93, 3.67
≥ 30
4.29
2.25, 8.17
Smoking (do you now smoke cigarettes?)
Indicator for lifestyle factors
Yes ("everyday" or "some days")
1.0
-
No ("not at all")
1.27
0.65, 2.49
Missing
0.86
0.51, 1.45
* We combined Mexican Americans and other Hispanics in NHANES to match the race categories in BRFSS.
† This variable was defined as a composite of multiple questions about physician contact for specific conditions in the BRFSS.
‡ BMI was corrected for bias in self-reported height and weight in telephone interviews, using methods described elsewhere
We estimated the individual-level probability of having diabetes in BRFSS 2003-2007 in two steps: First, participants who had answered "yes" to the diabetes diagnosis question were, by definition, assigned a probability of 1.0 for having diabetes. Second, the probability of having undiagnosed diabetes (i.e., FPG ≥ 126 mg/dL) for those who answered "no" to this question was estimated using the coefficients of the logistic regression fit on the NHANES dataset. Estimates of diabetes prevalence and diabetes diagnosis by age, sex, and state were obtained from the BRFSS using appropriate sample weights. The difference between total diabetes and self-reported diabetes is undiagnosed diabetes. In separate analyses, we used linear regressions to model the relationship between FPG as a continuous variable and self-reported diabetes diagnosis, medication use, and the health system, sociodemographic, and risk factor variables in Table
Results
The national prevalence of diabetes among US adults ≥ 30 years was 13.7% (95% Confidence Interval 12.0%, 15.4%) for men and 11.7% (CI95 10.4%, 13.0%) for women in the pooled 2003-2006 NHANES. Nationally, approximately 32% of all diabetes cases in 2003-2006 were undiagnosed, a percentage that has changed little since 1999-2002
Regression results
Among those who answered "no" to having been diagnosed with diabetes, being male and being older was associated with a higher probability of having diabetes (Table
We evaluated the performance of the prediction model using both internal and external validations. For internal validation, we applied the regression coefficients to NHANES 2003-2006 observations (i.e., the same data used in estimating the regression model) to predict diabetes prevalence. The differences between the predicted and actual diabetes prevalence for different age, sex, and race groups were on average 0.5 percentage points and at most 8.4 percentage points. The Pearson correlation coefficient for the observed and predicted diabetes prevalence for different age, sex, and race groups was 0.98. For external validation, we applied the coefficients of regressions estimated using the 2003- 2006 rounds to the same variables in pooled data from two previous rounds of NHANES (1999-2000 and 2001-2002). The observed-predicted differences for individual age, sex, and race groups were at the extreme slightly worse than those in the internal validation; specifically, the 60- to 69-year-old males from "other race" had a 20 percentage point discrepancy. This may, however, be because the composition of this race changed between the two surveys. The Pearson correlation coefficient for the observed and predicted diabetes prevalence for different age, sex, and race groups was 0.93. On average, the predicted prevalence was 0.1 percentage points higher than the actual prevalence (versus 0.5 lower percentage points in the internal validation).
National-level prevalence of diabetes and undiagnosed diabetes
The predicted national prevalence of diabetes in 2003-2007 was 14.4% (14.3%, 14.5%) for men and 11.4% (11.3%, 11.5%) in women. The only sociodemographic group whose predicted and measured prevalences were significantly different was the uninsured, who had an actual prevalence of 9.2% (7.4%, 11.0%) but a predicted prevalence of 11.9% (11.6%, 12.2%).
State-level prevalence of diabetes and undiagnosed diabetes
In 2003-2007, the lowest prevalence of diabetes was in the Midwest and the Northeast, including Vermont, Minnesota, Montana, and Colorado, with age-standardized prevalence ranging from 11.0% to 12.2% for men and 7.3% to 8.4% for women (Figure
Estimated prevalence (sampling standard error)* of total diabetes by state, age, sex, race and insurance status (Figures show actual prevalence; age-standardized figures available from authors).
State
Age group
Sex
Race
Insurance status
30-59 y
≥ 60 y
Men
Women
White
Black
Hispanic
Other races
Insured
Uninsured
National NHANES
8.4%
(.6)
23.6%
(.1)
13.7%
(.8)
11.7%
(.7)
11.4%
(.7)
18.3%
(1.0)
16.7%
(1.6)
11.1%
(1.5)
13.3%
(.7)
9.2%
(.9)
National BRFSS Prediction
8.4%
(.05)
23.8%
(.1)
14.4%
(.07)
11.4%
(.05)
11.9%
(.04)
17.3%
(.18)
16.3%
(.26)
11.3%
(.29)
13.0%
(.05)
11.9%
(.15)
Alabama
10.1%
(.3)
25%
(.54)
16.1%
(.45)
13.5%
(.33)
13.6%
(.3)
19%
(.69)
14.5%
(1.91)
11.7%
(1.81)
15%
(.3)
12.4%
(.71)
Alaska
6%
(.31)
21.8%
(1.09)
9.9%
(.5)
8.2%
(.47)
9.2%
(.38)
8.9%
(1.17)
11.7%
(2.25)
8.3%
(1.01)
9.3%
(.38)
7.8%
(.77)
Arizona
8.4%
(.41)
22.1%
(.65)
14.5%
(.58)
10.7%
(.42)
11.7%
(.38)
15%
(1.66)
17.8%
(1.28)
11.3%
(1.32)
12.9%
(.39)
11.1%
(.94)
Arkansas
9.1%
(.24)
21.4%
(.42)
14.5%
(.35)
11.7%
(.27)
12.6%
(.23)
17%
(.8)
13.6%
(1.66)
12.7%
(1.33)
13.5%
(.24)
10.5%
(.51)
California
8.3%
(.25)
25%
(.59)
14.4%
(.4)
11%
(.3)
10.7%
(.25)
15.4%
(.86)
16.2%
(.61)
10.5%
(.94)
12.9%
(.27)
11.2%
(.72)
Colorado
5.7%
(.17)
18.9%
(.41)
10.6%
(.26)
7.3%
(.2)
8%
(.17)
11.4%
(.86)
15%
(.67)
9.2%
(1.13)
9.1%
(.18)
7.7%
(.45)
Connecticut
6.5%
(.19)
20.6%
(.4)
12.4%
(.29)
9.3%
(.23)
10.3%
(.19)
16.7%
(1)
14.6%
(.97)
8.9%
(1.22)
10.8%
(.19)
10.8%
(.68)
Delaware
8.3%
(.31)
23.1%
(.56)
15%
(.45)
10.9%
(.34)
12.4%
(.3)
16.4%
(.92)
12.5%
(2)
9.3%
(1.35)
13%
(.29)
10.7%
(.95)
District of Columbia
8.1%
(.31)
26.3%
(.78)
12.9%
(.48)
13.3%
(.44)
5.4%
(.24)
18.1%
(.52)
9.2%
(1.24)
9.7%
(1.72)
13.1%
(.34)
12.8%
(1.05)
Florida
9%
(.25)
23.1%
(.39)
16.2%
(.36)
12%
(.26)
13%
(.23)
18%
(.83)
15.9%
(.7)
11.7%
(1.54)
14.3%
(.24)
12.3%
(.61)
Georgia
9.2%
(.25)
26.5%
(.5)
14.6%
(.37)
12.2%
(.28)
12.2%
(.24)
16.9%
(.57)
12.2%
(1.39)
9.9%
(1.25)
13.5%
(.25)
12.2%
(.62)
Hawaii
7.6%
(.3)
20.8%
(.59)
12.9%
(.44)
10.6%
(.36)
8.7%
(.34)
14%
(.7)
14.2%
(1.28)
12.4%
(.46)
11.9%
(.29)
9.3%
(.89)
Idaho
7.7%
(.24)
21.7%
(.45)
12.8%
(.35)
10.6%
(.27)
11.4%
(.23)
16.1%
(1.97)
16.4%
(1.45)
13.4%
(1.45)
12%
(.24)
10%
(.56)
Illinois
8.6%
(.27)
23.8%
(.49)
14.5%
(.4)
11.2%
(.28)
11.2%
(.22)
18.6%
(.88)
17.6%
(1.33)
9.8%
(1.49)
12.5%
(.24)
15.9%
(1.06)
Indiana
8.4%
(.22)
24.8%
(.45)
14.7%
(.33)
11.9%
(.26)
12.9%
(.22)
18%
(1.01)
15.7%
(1.7)
10.9%
(1.35)
13.3%
(.22)
12.3%
(.63)
Iowa
6.9%
(.2)
22.1%
(.41)
13.4%
(.31)
10.3%
(.25)
11.8%
(.2)
14.7%
(1.69)
15.7%
(1.85)
4.6%
(1.15)
11.9%
(.21)
10.5%
(.69)
Kansas
7.3%
(.17)
21.7%
(.35)
13%
(.26)
10.4%
(.21)
11.3%
(.17)
17.1%
(.95)
14.3%
(1.03)
10.6%
(1.17)
11.8%
(.17)
10.7%
(.55)
Kentucky
9.8%
(.27)
24.7%
(.47)
15.7%
(.4)
12.5%
(.28)
13.7%
(.24)
20.8%
(1.55)
15.1%
(1.96)
11.8%
(1.83)
14.3%
(.26)
12.2%
(.61)
Louisiana
10%
(.26)
26.6%
(.5)
15.7%
(.38)
13.6%
(.29)
13%
(.26)
18.8%
(.56)
16.3%
(1.61)
13.1%
(1.31)
14.5%
(.26)
15.1%
(.59)
Maine
7.6%
(.26)
22.2%
(.52)
14.1%
(.4)
10.3%
(.29)
12.1%
(.25)
16.6%
(3.06)
11.2%
(1.78)
11.4%
(1.8)
12.4%
(.26)
9.2%
(.65)
Maryland
7.7%
(.22)
24.7%
(.51)
13.5%
(.35)
11%
(.28)
11.2%
(.21)
15.4%
(.57)
12%
(1.71)
8.8%
(1.12)
12.3%
(.23)
10.6%
(.77)
Massachusetts
6.4%
(.16)
20.5%
(.35)
12.2%
(.25)
9%
(.19)
10%
(.16)
14.8%
(.78)
17.6%
(.91)
7.9%
(.84)
10.5%
(.16)
10.7%
(.61)
Michigan
8.7%
(.23)
25.1%
(.43)
15%
(.34)
12%
(.26)
12.6%
(.21)
18.2%
(.81)
17.7%
(1.83)
14.3%
(1.55)
13.7%
(.22)
10.6%
(.65)
Minnesota
5.9%
(.2)
20.1%
(.45)
11.8%
(.32)
8%
(.23)
9.8%
(.2)
11.9%
(1.42)
12.2%
(1.68)
10.4%
(1.49)
10%
(.21)
7.2%
(.66)
Mississippi
11.4%
(.27)
27.7%
(.48)
16.9%
(.39)
15.6%
(.3)
14.3%
(.27)
20.4%
(.51)
16%
(1.84)
16.9%
(2.21)
16.6%
(.27)
14.3%
(.61)
Missouri
7.7%
(.26)
22.9%
(.52)
13.7%
(.39)
11.3%
(.31)
12%
(.26)
16%
(.98)
14.2%
(2.4)
13.3%
(1.65)
12.7%
(.27)
10.4%
(.62)
Montana
6.5%
(.21)
19.3%
(.43)
11.7%
(.31)
9.3%
(.26)
10.1%
(.21)
19.3%
(1.97)
13.4%
(1.76)
14.3%
(1.08)
10.6%
(.22)
10%
(.54)
Nebraska
7.3%
(.21)
22.4%
(.39)
13.3%
(.31)
10.6%
(.24)
11.7%
(.2)
15.7%
(1.53)
16.4%
(1.39)
8.6%
(1.36)
12%
(.21)
11.1%
(.61)
Nevada
7.5%
(.34)
23.3%
(.73)
13.9%
(.5)
10.1%
(.43)
12%
(.38)
15.1%
(1.4)
12.9%
(1.03)
8.8%
(.96)
12.2%
(.35)
11.3%
(.95)
New Hampshire
6.5%
(.18)
22.2%
(.43)
12.2%
(.28)
9.5%
(.23)
10.7%
(.19)
12.1%
(1.94)
17%
(2.5)
12.2%
(1.44)
11.1%
(.2)
7.9%
(.48)
New Jersey
7.9%
(.18)
23.9%
(.34)
14.4%
(.27)
11%
(.21)
11.3%
(.16)
17.5%
(.58)
16.1%
(.69)
10%
(.88)
12.7%
(.17)
12.4%
(.59)
New Mexico
8.4%
(.22)
22.3%
(.42)
13.5%
(.31)
11.6%
(.26)
10.2%
(.23)
14.3%
(.78)
16.4%
(.43)
14.3%
(1.15)
12.6%
(.22)
12.3%
(.49)
New York
8.5%
(.23)
23.9%
(.46)
14.7%
(.35)
11.5%
(.27)
11.5%
(.21)
18.1%
(.74)
15.6%
(.86)
11.5%
(1.08)
13.3%
(.23)
10.9%
(.69)
North Carolina
9.3%
(.17)
25.6%
(.33)
15.4%
(.26)
12.8%
(.2)
13%
(.18)
19.2%
(.44)
11%
(.73)
12%
(.92)
14.3%
(.17)
12.3%
(.41)
North Dakota
6.5%
(.22)
21.7%
(.49)
12.7%
(.35)
10.1%
(.3)
11.1%
(.23)
14.9%
(2.37)
19.1%
(3.06)
15.5%
(1.83)
11.2%
(.23)
12.9%
(.9)
Ohio
8.3%
(.27)
24.6%
(.57)
14.6%
(.41)
11.9%
(.33)
12.6%
(.28)
18.4%
(.96)
16.5%
(2.91)
14.8%
(2.05)
13.1%
(.28)
13.9%
(.94)
Oklahoma
9.7%
(.22)
24.1%
(.37)
15.7%
(.31)
12.9%
(.24)
13.1%
(.2)
18.1%
(.77)
18.3%
(1.39)
17.4%
(.8)
14.8%
(.22)
11.4%
(.47)
Oregon
7.1%
(.21)
21.1%
(.4)
13.1%
(.32)
9.6%
(.23)
11.2%
(.2)
13.2%
(1.14)
11.7%
(1.34)
11.2%
(1.36)
11.6%
(.21)
9.0%
(.56)
Pennsylvania
8.1%
(.23)
24.1%
(.43)
15.1%
(.36)
11.6%
(.25)
12.7%
(.21)
17.7%
(.99)
19.1%
(2.16)
12.8%
(1.71)
13.6%
(.23)
10.4%
(.66)
Rhode Island
7%
(.23)
22.7%
(.5)
13.7%
(.37)
10.3%
(.29)
11.7%
(.24)
15.4%
(1.39)
16.9%
(1.31)
6.7%
(1.15)
12.1%
(.25)
10.3%
(.78)
South Carolina
10%
(.22)
26%
(.4)
15.8%
(.32)
13.4%
(.26)
12.6%
(.2)
20.4%
(.55)
18.7%
(1.91)
10.5%
(1.17)
14.7%
(.22)
14.0%
(.57)
South Dakota
7%
(.19)
21.5%
(.37)
13%
(.28)
10.3%
(.23)
11.2%
(.18)
17.7%
(1.69)
16.5%
(2.2)
18.9%
(1.18)
11.7%
(.19)
10.9%
(.56)
Tennessee
10.5%
(.37)
26.3%
(.6)
16.3%
(.53)
13.8%
(.38)
14.6%
(.32)
17.9%
(1.18)
13.3%
(2.41)
13.6%
(2.67)
15.4%
(.35)
12.0%
(.78)
Texas
10.1%
(.25)
25.4%
(.46)
15.2%
(.35)
13%
(.28)
12.2%
(.26)
17.1%
(.65)
18.6%
(.6)
12%
(1.17)
14.3%
(.25)
13.4%
(.5)
Utah
6.3%
(.22)
22.7%
(.56)
12%
(.35)
8.7%
(.28)
10%
(.23)
14%
(1.96)
14%
(1.4)
11.1%
(1.59)
10.6%
(.24)
8.1%
(.62)
Vermont
6.1%
(.16)
19.9%
(.37
11.7%
(.26)
8.6%
(.2)
10%
(.16)
13.3%
(1.65)
14.9%
(2.03)
11.8%
(1.47)
10.3%
(.17)
8.4%
(.49)
Virginia
7.7%
(.24)
23.6%
(.58)
13.5%
(.39)
10.5%
(.31)
11.3%
(.26)
16.8%
(.81)
11.3%
(1.15)
10%
(1.49)
11.9%
(.25)
12.6%
(.95)
Washington
7.4%
(.12)
21.3%
(.23)
12.5%
(.17)
9.9%
(.13)
11.1%
(.11)
13.5%
(.69)
13.4%
(.64)
10.7%
(.56)
11.4%
(.12)
10.0%
(.35)
West Virginia
11.1%
(.31)
27.3%
(.53)
17.6%
(.44)
15.4%
(.36)
16.4%
(.29)
19%
(1.85)
15.1%
(2.14)
17.1%
(1.87)
17.2%
(.31)
11.9%
(.72)
Wisconsin
6.3%
(.2)
21.6%
(.49)
12.1%
(.32)
9.4%
(.26)
10.4%
(.21)
17.2%
(1.34)
14.6%
(2.22)
10.6%
(1.64)
10.7%
(.22)
11.9%
(.8)
Wyoming
7.3%
(.22)
21.2%
(.43)
12.8%
(.32)
9.8%
(.25)
10.8%
(.2)
16.2%
(2.07)
20.4%
(1.58)
15.6%
(1.86)
11.5%
(.22)
10.0%
(.54)
* The standard error of prevalence reported here reflects the sampling variability in the predicted diabetes prevalence but does not incorporate uncertainty in the prediction model (parameter uncertainty and stochastic uncertainty) and thus is an underestimate for the true standard error of prevalence. We included the parameter and stochastic uncertainty of the modeling using a multiple imputation approach in which we imputed the prevalence of diabetes for individuals who did not report having diabetes 10 times, drawing from a multivariate Normal distribution of the coefficients and drawing randomly from the posterior binomial distribution of revalence. We estimated the standard error of the national prevalence of diabetes using these 10 imputed values for each sex. The standard error was 0.8% for men and 0.4% for women, which is almost 10 times larger than the standard error estimated using sampling uncertainty only.
Estimated prevalence of total diabetes by state, sex, and age group
Estimated prevalence of total diabetes by state, sex, and age group. Within each age group, figures are age-standardized to the 2000 U.S. population.
Age-standardized diabetes prevalence was higher in men than women in all states, with the largest differences in Minnesota, Colorado, Utah, and Maine, where prevalence in men was 32% to 38% higher than among women. The smallest male-female differences were in the District of Columbia, Mississippi, West Virginia, and Louisiana, ranging from 6% to 18% (Figures
Relationship between male and female diabetes prevalence, by age
Relationship between male and female diabetes prevalence, by age. Each data point corresponds to one state.
The age-standardized proportions of diabetes cases that were undiagnosed were lowest in Hawaii, Mississippi, West Virginia, and Tennessee (19.5% to 21.4% of all diabetes cases) and highest in Minnesota, Montana, North Dakota, Vermont, and Colorado (31.1% to 33.3% of all diabetes cases). However, the absolute prevalence of undiagnosed diabetes, as a percent of total population, was highest in New Mexico, Texas, Florida, and California (3.5 to 3.7 percentage points) and lowest in Montana, Oklahoma, Oregon, Alaska, Vermont, Utah, Washington, and Hawaii (2.1 to 3.0 percentage points) (see Table
Estimated prevalence (sampling standard error)* of undiagnosed diabetes by state, age, sex, race, and insurance (Figures show actual prevalence; age-standardized figures available from authors).
State
Age group
Sex
Race
Insurance status
30-59 y
≥ 60 y
Men
Women
White
Black
Hispanic
Other races
Insured
Uninsured
National NHANES
2.1%
(.4)
6.7%
(.9)
4.5%
(.6)
2.3%
(.4)
3.4%
(.5)
3.3%
(.6)
4.4%
(1.1)
.5%
(.5)
3.4%
(.4)
3.2%
(.7)
National BRFSS Prediction
2.1%
(<.01)
6.4%
(.01)
4.3%
(0.1)
2.5%
(<.01)
3.3%
(<.01)
3.3%
(.02)
5.4%
(.05)
.7%
(.01)
3.3%
(<.01)
3.9%
(0.02)
Alabama
2.1%
(.03)
6.2%
(.09)
4.3%
(.07)
2.5%
(.03)
3.4%
(.04)
3.5%
(.08)
5.9%
(.43)
.9%
(.07)
3.3%
(.04)
3.8%
(.12)
Alaska
1.9%
(.04)
6.3%
(.18)
3.5%
(.09)
1.9%
(.05)
3%
(.06)
3.5%
(.21)
5.3%
(.55)
.9%
(.04)
2.7%
(.06)
2.9%
(.13)
Arizona
2.2%
(.05)
6.3%
(.12)
4.4%
(.09)
2.5%
(.05)
3.4%
(.05)
2.8%
(.15)
5.1%
(.24)
.7%
(.07)
3.4%
(.06)
4%
(.16)
Arkansas
2.1%
(.02)
6.2%
(.07)
4.4%
(.06)
2.5%
(.03)
3.5%
(.03)
3.4%
(.1)
5.6%
(.39)
.9%
(.04)
3.4%
(.03)
3.7%
(.1)
California
2.4%
(.04)
6.3%
(.11)
4.5%
(.08)
2.5%
(.04)
3.1%
(.03)
3.4%
(.12)
5.3%
(.13)
.7%
(.03)
3.3%
(.04)
4.3%
(.14)
Colorado
2%
(.02)
6.2%
(.07)
3.8%
(.05)
2.2%
(.02)
2.8%
(.03)
2.9%
(.11)
5.2%
(.15)
.7%
(.04)
2.9%
(.03)
3.5%
(.12)
Connecticut
2%
(.02)
6.4%
(.07)
4.2%
(.05)
2.4%
(.03)
3.3%
(.03)
3.1%
(.13)
5.1%
(.22)
.6%
(.04)
3.2%
(.03)
4.1%
(.15)
Delaware
2%
(.03)
6.5%
(.09)
4.3%
(.08)
2.5%
(.04)
3.5%
(.05)
3.2%
(.12)
4.7%
(.44)
.7%
(.05)
3.4%
(.04)
3.5%
(.18)
District of Columbia
1.9%
(.03)
6.2%
(.12)
3.8%
(.08)
2.4%
(.05)
2.4%
(.04)
3.5%
(.07)
4.4%
(.3)
.6%
(.05)
3%
(.05)
4%
(.2)
Florida
2.3%
(.03)
6.9%
(.08)
5.1%
(.07)
2.9%
(.04)
3.8%
(.04)
3.5%
(.11)
6.2%
(.18)
.8%
(.05)
3.9%
(.04)
4.4%
(.13)
Georgia
2%
(.02)
6.1%
(.08)
3.8%
(.05)
2.2%
(.02)
3.1%
(.03)
3%
(.06)
4.7%
(.32)
.7%
(.04)
2.9%
(.03)
3.4%
(.1)
Hawaii
1.4%
(.02)
4.2%
(.08)
3.1%
(.06)
1.5%
(.03)
3.4%
(.06)
3.5%
(.1)
4.9%
(.23)
.9%
(.02)
2.3%
(.03)
2.7%
(.14)
Idaho
1.9%
(.02)
6.2%
(.08)
4.1%
(.06)
2.2%
(.03)
3.2%
(.03)
3.1%
(.23)
5.2%
(.31)
.7%
(.04)
3.1%
(.03)
3.4%
(.1)
Illinois
2.1%
(.03)
6.5%
(.09)
4.2%
(.07)
2.5%
(.03)
3.3%
(.03)
3.2%
(.1)
5.4%
(.25)
.6%
(.04)
3.2%
(.04)
4.0%
(.15)
Indiana
2%
(.02)
6.1%
(.07)
4.1%
(.05)
2.4%
(.03)
3.3%
(.03)
3.3%
(.11)
4.8%
(.27)
.8%
(.05)
3.2%
(.03)
3.5%
(0.1)
Iowa
2%
(.02)
6.6%
(.07)
4.4%
(.06)
2.6%
(.03)
3.5%
(.03)
3.5%
(.23)
6%
(.48)
.7%
(.06)
3.5%
(.03)
4.1%
(.16)
Kansas
2%
(.02)
6.2%
(.06)
4.2%
(.04)
2.4%
(.02)
3.3%
(.03)
3.2%
(.11)
4.9%
(.18)
.8%
(.04)
3.3%
(.02)
3.6%
(.09)
Kentucky
2.1%
(.03)
6.1%
(.07)
4.2%
(.06)
2.4%
(.03)
3.3%
(.03)
3.3%
(.15)
5.8%
(.44)
.8%
(.07)
3.2%
(.03)
3.4%
(.09)
Louisiana
2.2%
(.03)
6.7%
(.09)
4.4%
(.06)
2.6%
(.03)
3.5%
(.04)
3.5%
(.07)
5.4%
(.36)
1%
(.06)
3.4%
(.04)
3.8%
(.09)
Maine
2%
(.02)
6.3%
(.09)
4.2%
(.06)
2.4%
(.03)
3.3%
(.04)
3.1%
(.42)
5.5%
(.59)
.9%
(.07)
3.3%
(.04)
3.8%
(.14)
Maryland
2%
(.02)
6.4%
(.08)
4.1%
(.06)
2.3%
(.03)
3.3%
(.03)
3.3%
(.07)
4.8%
(.32)
.7%
(.06)
3.1%
(.03)
3.7%
(.14)
Massachusetts
1.9%
(.02)
6.3%
(.06)
4.1%
(.05)
2.3%
(.02)
3.2%
(.03)
3%
(.13)
4.9%
(.19)
.6%
(.03)
3.1%
(.03)
3.9%
(.15)
Michigan
2%
(.02)
6.4%
(.07)
4.2%
(.05)
2.4%
(.03)
3.4%
(.03)
3.2%
(.09)
5.6%
(.46)
.7%
(.04)
3.3%
(.03)
3.4%
(.11)
Minnesota
1.9%
(.02)
6.6%
(.08)
4.1%
(.06)
2.4%
(.03)
3.3%
(.03)
2.9%
(.17)
6%
(.51)
.6%
(.05)
3.2%
(.03)
3.6%
(.15)
Mississippi
2.1%
(.02)
6.1%
(.08)
4.3%
(.06)
2.4%
(.03)
3.3%
(.04)
3.3%
(.06)
6.5%
(.47)
.8%
(.07)
3.3%
(.03)
3.6%
(0.1)
Missouri
2%
(.03)
6.2%
(.09)
4.2%
(.07)
2.4%
(.03)
3.4%
(.04)
3.6%
(.15)
4.8%
(.37)
.8%
(.06)
3.3%
(.04)
3.5%
(.13)
Montana
2%
(.02)
6.3%
(.08)
4.2%
(.06)
2.4%
(.03)
3.4%
(.04)
3%
(.19)
5.1%
(.38)
.8%
(.03)
3.3%
(.04)
3.4%
(.09)
Nebraska
2%
(.02)
6.4%
(.06)
4.3%
(.05)
2.5%
(.03)
3.4%
(.03)
3.2%
(.16)
5.3%
(.28)
.8%
(.06)
3.3%
(.03)
3.9%
(.11)
Nevada
2.1%
(.04)
6.3%
(.13)
4.3%
(.09)
2.3%
(.05)
3.4%
(.06)
3.3%
(.18)
5.4%
(.26)
.7%
(.04)
3.3%
(.05)
3.8%
(.19)
New Hampshire
1.9%
(.02)
6.5%
(.07)
4.1%
(.05)
2.3%
(.03)
3.2%
(.03)
2.8%
(.24)
5.3%
(.54)
.8%
(.06)
3.2%
(.03)
3.2%
(.11)
New Jersey
2.2%
(.02)
6.6%
(.07)
4.5%
(.05)
2.6%
(.02)
3.4%
(.03)
3.5%
(.08)
5.7%
(.18)
.6%
(.03)
3.4%
(.03)
4.5%
(.16)
New Mexico
2.6%
(.03)
7%
(.09)
4.9%
(.07)
2.9%
(.03)
3.3%
(.04)
3.4%
(.1)
5.7%
(.1)
.8%
(.03)
3.8%
(.04)
4.4%
(.12)
New York
2.1%
(.03)
6.6%
(.08)
4.4%
(.06)
2.6%
(.03)
3.4%
(.03)
3.3%
(.09)
5.8%
(.21)
.8%
(.04)
3.4%
(.04)
4.1%
(.16)
North Carolina
2.1%
(.02)
6.2%
(.05)
4.2%
(.04)
2.4%
(.02)
3.3%
(.02)
3.6%
(.06)
5.2%
(.24)
.8%
(.03)
3.2%
(.02)
3.8%
(.08)
North Dakota
2.1%
(.03)
6.7%
(.09)
4.5%
(.07)
2.6%
(.04)
3.6%
(.04)
3.4%
(.29)
7.6%
(.73)
.9%
(.07)
3.5%
(.04)
3.8%
(.15)
Ohio
2%
(.03)
6.5%
(.1)
4.3%
(.07)
2.5%
(.04)
3.4%
(.04)
3.4%
(.12)
6.3%
(.68)
.8%
(.06)
3.4%
(.04)
3.6%
(.14)
Oklahoma
2%
(.02)
5.9%
(.06)
4.1%
(.05)
2.4%
(.02)
3.4%
(.03)
3.4%
(.09)
5.8%
(.31)
.9%
(.03)
3.2%
(.03)
3.3%
(.08)
Oregon
1.9%
(.02)
6.1%
(.07)
4.1%
(.05)
2.3%
(.02)
3.3%
(.03)
3%
(.14)
4.1%
(.23)
.8%
(.04)
3.1%
(.03)
3.4%
(0.1)
Pennsylvania
2%
(.02)
6.4%
(.07)
4.3%
(.06)
2.6%
(.03)
3.5%
(.03)
3.4%
(.12)
5.1%
(.38)
.7%
(.06)
3.4%
(.03)
3.7%
(.14)
Rhode Island
2.1%
(.03)
6.5%
(.08)
4.4%
(.07)
2.6%
(.03)
3.5%
(.04)
2.9%
(.17)
5.2%
(.26)
.8%
(.06)
3.4%
(.04)
4.3%
(.17)
South Carolina
2.1%
(.02)
6.1%
(.06)
4.1%
(.05)
2.4%
(.02)
3.3%
(.03)
3.3%
(.06)
5.5%
(.41)
.8%
(.05)
3.2%
(.03)
3.6%
(.08)
South Dakota
2%
(.02)
6.4%
(.06)
4.4%
(.05)
2.5%
(.03)
3.5%
(.03)
3.5%
(.24)
6.4%
(.5)
.8%
(.03)
3.4%
(.03)
3.7%
(.12)
Tennessee
2.1%
(.03)
6.1%
(.09)
4.1%
(.07)
2.4%
(.03)
3.3%
(.04)
3.2%
(.12)
5.6%
(.5)
.7%
(.07)
3.2%
(.04)
3.7%
(.13)
Texas
2.5%
(.03)
6.7%
(.09)
4.5%
(.06)
2.6%
(.03)
3.3%
(.03)
3.2%
(.09)
5.4%
(.11)
.7%
(.04)
3.4%
(.04)
4.3%
(.09)
Utah
1.8%
(.02)
6%
(.09)
3.6%
(.05)
2.1%
(.03)
2.8%
(.03)
2.8%
(.19)
4.6%
(.22)
.6%
(.05)
2.8%
(.03)
3.1%
(.11)
Vermont
1.9%
(.02)
6.3%
(.06)
4%
(.04)
2.3%
(.02)
3.2%
(.03)
3.7%
(.26)
5.5%
(.43)
.9%
(.06)
3.1%
(.03)
3.5%
(.1)
Virginia
1.9%
(.03)
6.2%
(.09)
3.9%
(.06)
2.3%
(.03)
3.2%
(.04)
3.2%
(.09)
5.4%
(.35)
.7%
(.05)
3%
(.04)
3.7%
(.14)
Washington
1.9%
(.01)
6.1%
(.04)
3.9%
(.03)
2.2%
(.01)
3.1%
(.02)
2.9%
(.08)
4.6%
(.13)
.7%
(.02)
3%
(.02)
3.3%
(.06)
West Virginia
2.2%
(.03)
6.2%
(.08)
4.5%
(.07)
2.6%
(.03)
3.6%
(.04)
3.8%
(.23)
6.3%
(.58)
.9%
(.06)
3.6%
(.04)
3.3%
(0.1)
Wisconsin
1.9%
(.02)
6.5%
(.08)
4.2%
(.06)
2.4%
(.03)
3.3%
(.04)
3.2%
(.14)
4.9%
(.4)
.8%
(.07)
3.2%
(.04)
4.0%
(.15)
Wyoming
2.1%
(.02)
6.5%
(.08)
4.3%
(.06)
2.4%
(.03)
3.4%
(.03)
3.5%
(.24)
5.7%
(.3)
.9%
(.05)
3.3%
(.03)
3.6%
(.11)
* The standard error of prevalence reported here reflects the sampling variability in the predicted diabetes prevalence but does not incorporate uncertainty in the prediction model (parameter uncertainty and stochastic uncertainty) and thus is an underestimate for the true standard error of prevalence. See footnote to Table 2 for an example of how the inclusion of these sources would affect standard errors.
Men in all states had higher proportions of undiagnosed diabetes than women, with the male-female difference in undiagnosed proportion being largest in Hawaii, Mississippi, District of Columbia, West Virginia, and Idaho, where the proportion undiagnosed among men was 34.1% to 39.0% higher than among women. The male-female diagnosis disparity was smallest in Colorado, Pennsylvania, Vermont, and Minnesota (12.9% to 19.8%). When stratified on race, the proportion of cases undiagnosed was highest among Hispanics (33%), followed by whites (28%) and blacks (19%), and it was lowest in the residual group of "other races" (6%). One-third of diabetes cases were undiagnosed in participants who did not have insurance compared to one-fourth among insured Americans.
Discussion
To our knowledge, this is the first study to estimate the total prevalence of diabetes and the proportion of diabetes that is undiagnosed at the state level. The Southern and Appalachian states had the highest diabetes prevalence, with Mississippi faring the worst. The Northern plains, the Northeast and the Midwest had the lowest prevalence. Prevalence of undiagnosed diabetes also varied across states, with Southern states and California having the highest prevalence. The proportion of undiagnosed diabetes was higher in men, Hispanics, and the uninsured compared to women, whites and insured. In fact, one-half of diabetes cases were undiagnosed in uninsured Hispanic men. These findings are important for the development and implementation of adequate state programs to prevent, diagnose, and control diabetes.
This analysis has a number of limitations: First, although our regression models included important sociodemographic, lifestyle, and health system determinants of diabetes risk and diagnosis, there are other factors that affect diabetes, such as diet and quality of care
Despite uncertainties, our results currently provide the only estimates of total diabetes and undiagnosed diabetes in U.S. states, and should provide motivation, guidance, and benchmarks for designing, implementing, and evaluating diabetes prevention and control programs at the state level. Further, our methods allow states to combine the relatively low-cost BRFSS telephone survey with NHANES to regularly monitor the prevalence of diabetes and progress in diabetes diagnosis.
Increasing the coverage of lifestyle, e.g., physical activity and pharmacological interventions for diabetes, should be a priority in states with high diabetes prevalence. Some states also need to improve diagnosis, especially among men, because early diagnosis and intensive glycemic control reduces the future incidence of microvascular complications
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
GD, CJM and ME designed the study. GD, ABF and SO conducted the analyses. GD and ME wrote the paper with input from other authors. ME oversaw the research and acts as the paper's guarantor. All authors have read and confirmed the final manuscript.