An improved understanding of which groups are more likely to be unaware of their diabetes may lead to more efficient screening, improved awareness, and overall better treatment for diabetes. Our objective was to investigate factors associated with being unaware of having diabetes among adults with diagnosed and undiagnosed diabetes.

The 2011–2014 National Health and Nutrition Examination Survey (NHANES) is a stratified, multistage probability survey representative of the civilian, noninstitutionalized U.S. population (1). Data were collected during an in-home interview and a visit to a mobile examination center. We used data from 1,879 participants with either diagnosed or undiagnosed diabetes (based on a single measurement of A1C, fasting plasma glucose, or 2-h plasma glucose).

Using logistic regression, we calculated odds ratios of being unaware of diabetes associated with age, race/ethnicity, sex, gestational diabetes mellitus (GDM), family history of diabetes, education, household income, smoking status, BMI, work-time activity, leisure-time activity, no health insurance, location of routine health care, no health care in the past year, hospitalization in the past year, hypertension, and hyperlipidemia. Initial models were unadjusted and subsequent models adjusted for all other variables. We repeated the analysis stratified by sex. Appropriate sample weights were used so that the sum added to the total civilian noninstitutionalized U.S. population (2).

Table 1

Odds ratios (95% CI) of being unaware of having diabetes among people with diabetes, U.S., 2011–2014

OverallOverallMenWomen
Age
20–44 years Reference Reference Reference Reference
45–64 years 0.66 (0.45–0.97) 0.76 (0.51–1.13) 1.02 (0.55–1.89) 0.53 (0.27–1.05)
≥65 years 0.70 (0.48–1.01) 0.99 (0.68–1.44) 0.92 (0.51–1.67) 1.17 (0.63–2.18)
Race/ethnicity
Non-Hispanic white Reference Reference Reference Reference
Non-Hispanic black 0.86 (0.56–1.32) 1.11 (0.75–1.64) 0.93 (0.51–1.70) 1.46 (0.85–2.49)
Non-Hispanic Asian 1.74 (1.18–2.58) 1.44 (0.82–2.54) 1.52 (0.66–3.49) 1.72 (0.68–4.39)
Mexican American 1.23 (0.86–1.76) 1.06 (0.73–1.53) 0.62 (0.34–1.11) 1.91 (1.09–3.34)
Other Hispanic 1.69 (1.08–2.62) 1.30 (0.78–2.14) 0.96 (0.40–2.30) 2.21 (1.12–4.34)
Sex and GDM status
Women without GDM Reference Reference — Reference
Women with GDM 1.02 (0.68–1.51) 1.06 (0.68–1.65) — 1.04 (0.65–1.65)
Men 1.23 (0.84–1.79) 1.07 (0.71–1.61) — —
Family history of diabetes 0.53 (0.39–0.72) 0.48 (0.33–0.70) 0.43 (0.25–0.76) 0.53 (0.32–0.88)
Education
Greater than high school education Reference Reference Reference Reference
High school education 0.99 (0.66–1.48) 1.07 (0.65–1.78) 0.85 (0.40–1.82) 1.17 (0.63–2.18)
Less than high school education 1.02 (0.67–1.57) 0.98 (0.56–1.70) 1.23 (0.59–2.57) 0.65 (0.34–1.26)
Household income <$20,000 0.84 (0.62–1.14) 0.88 (0.65–1.21) 1.05 (0.67–1.65) 0.85 (0.50–1.45) Smoking status Never smokers Reference Reference Reference Reference Former smokers 0.97 (0.71–1.31) 0.96 (0.63–1.46) 1.06 (0.60–1.87) 0.82 (0.39–1.71) Current smokers 0.84 (0.60–1.17) 0.75 (0.51–1.12) 0.63 (0.37–1.08) 1.09 (0.49–2.44) BMI <25 kg/m2 Reference Reference Reference Reference 25–29.9 kg/m2 1.15 (0.79–1.67) 1.17 (0.66–2.07) 2.56 (1.23–5.30) 0.53 (0.24–1.21) 30–34.9 kg/m2 0.90 (0.52–1.56) 0.95 (0.45–1.99) 2.04 (0.69–6.03) 0.49 (0.18–1.31) ≥35 kg/m2 0.70 (0.43–1.15) 0.77 (0.39–1.53) 1.52 (0.53–4.35) 0.47 (0.21–1.05) Low work-time activity levels 0.86 (0.59–1.23) 0.74 (0.48–1.12) 0.66 (0.39–1.14) 0.77 (0.44–1.34) Low leisure-time activity levels 1.03 (0.74–1.43) 1.13 (0.78–1.64) 0.99 (0.58–1.68) 1.43 (0.85–2.40) No health insurance 1.79 (1.29–2.48) 1.25 (0.74–2.11) 1.21 (0.64–2.27) 1.32 (0.61–2.83) Routine health care location Health care at doctor’s office or HMO Reference Reference Reference Reference Other place for health care 0.90 (0.61–1.34) 0.68 (0.41–1.11) 0.82 (0.48–1.40) 0.51 (0.30–0.90) No routine place for health care 2.61 (1.68–4.05) 0.79 (0.43–1.47) 1.00 (0.52–1.89) 0.89 (0.29–2.73) No health care in the past year 5.88 (3.47–9.99) 5.85 (2.39–14.34) 5.12 (1.54–17.06) 7.03 (2.67–18.51) Hospitalized in the past year 0.54 (0.41–0.73) 0.66 (0.44–0.99) 0.57 (0.26–1.27) 0.67 (0.38–1.17) Hypertension 0.68 (0.51–0.91) 0.74 (0.53–1.02) 0.66 (0.39–1.12) 0.78 (0.46–1.30) Hyperlipidemia 0.81 (0.57–1.14) 0.80 (0.51–1.24) 0.96 (0.57–1.63) 0.65 (0.34–1.24) UnadjustedAdjusted OverallOverallMenWomen Age 20–44 years Reference Reference Reference Reference 45–64 years 0.66 (0.45–0.97) 0.76 (0.51–1.13) 1.02 (0.55–1.89) 0.53 (0.27–1.05) ≥65 years 0.70 (0.48–1.01) 0.99 (0.68–1.44) 0.92 (0.51–1.67) 1.17 (0.63–2.18) Race/ethnicity Non-Hispanic white Reference Reference Reference Reference Non-Hispanic black 0.86 (0.56–1.32) 1.11 (0.75–1.64) 0.93 (0.51–1.70) 1.46 (0.85–2.49) Non-Hispanic Asian 1.74 (1.18–2.58) 1.44 (0.82–2.54) 1.52 (0.66–3.49) 1.72 (0.68–4.39) Mexican American 1.23 (0.86–1.76) 1.06 (0.73–1.53) 0.62 (0.34–1.11) 1.91 (1.09–3.34) Other Hispanic 1.69 (1.08–2.62) 1.30 (0.78–2.14) 0.96 (0.40–2.30) 2.21 (1.12–4.34) Sex and GDM status Women without GDM Reference Reference — Reference Women with GDM 1.02 (0.68–1.51) 1.06 (0.68–1.65) — 1.04 (0.65–1.65) Men 1.23 (0.84–1.79) 1.07 (0.71–1.61) — — Family history of diabetes 0.53 (0.39–0.72) 0.48 (0.33–0.70) 0.43 (0.25–0.76) 0.53 (0.32–0.88) Education Greater than high school education Reference Reference Reference Reference High school education 0.99 (0.66–1.48) 1.07 (0.65–1.78) 0.85 (0.40–1.82) 1.17 (0.63–2.18) Less than high school education 1.02 (0.67–1.57) 0.98 (0.56–1.70) 1.23 (0.59–2.57) 0.65 (0.34–1.26) Household income <$20,000 0.84 (0.62–1.14) 0.88 (0.65–1.21) 1.05 (0.67–1.65) 0.85 (0.50–1.45)
Smoking status
Never smokers Reference Reference Reference Reference
Former smokers 0.97 (0.71–1.31) 0.96 (0.63–1.46) 1.06 (0.60–1.87) 0.82 (0.39–1.71)
Current smokers 0.84 (0.60–1.17) 0.75 (0.51–1.12) 0.63 (0.37–1.08) 1.09 (0.49–2.44)
BMI
<25 kg/m2 Reference Reference Reference Reference
25–29.9 kg/m2 1.15 (0.79–1.67) 1.17 (0.66–2.07) 2.56 (1.23–5.30) 0.53 (0.24–1.21)
30–34.9 kg/m2 0.90 (0.52–1.56) 0.95 (0.45–1.99) 2.04 (0.69–6.03) 0.49 (0.18–1.31)
≥35 kg/m2 0.70 (0.43–1.15) 0.77 (0.39–1.53) 1.52 (0.53–4.35) 0.47 (0.21–1.05)
Low work-time activity levels 0.86 (0.59–1.23) 0.74 (0.48–1.12) 0.66 (0.39–1.14) 0.77 (0.44–1.34)
Low leisure-time activity levels 1.03 (0.74–1.43) 1.13 (0.78–1.64) 0.99 (0.58–1.68) 1.43 (0.85–2.40)
No health insurance 1.79 (1.29–2.48) 1.25 (0.74–2.11) 1.21 (0.64–2.27) 1.32 (0.61–2.83)
Routine health care location
Health care at doctor’s office or HMO Reference Reference Reference Reference
Other place for health care 0.90 (0.61–1.34) 0.68 (0.41–1.11) 0.82 (0.48–1.40) 0.51 (0.30–0.90)
No routine place for health care 2.61 (1.68–4.05) 0.79 (0.43–1.47) 1.00 (0.52–1.89) 0.89 (0.29–2.73)
No health care in the past year 5.88 (3.47–9.99) 5.85 (2.39–14.34) 5.12 (1.54–17.06) 7.03 (2.67–18.51)
Hospitalized in the past year 0.54 (0.41–0.73) 0.66 (0.44–0.99) 0.57 (0.26–1.27) 0.67 (0.38–1.17)
Hypertension 0.68 (0.51–0.91) 0.74 (0.53–1.02) 0.66 (0.39–1.12) 0.78 (0.46–1.30)
Hyperlipidemia 0.81 (0.57–1.14) 0.80 (0.51–1.24) 0.96 (0.57–1.63) 0.65 (0.34–1.24)

HMO, health maintenance organization.

Adjusted for all other variables listed in the table. Odds ratios in boldface type are statistically significant at P < 0.05.

Among men, having a family history of diabetes, having a BMI 25.0–29.9 kg/m2, and receiving no health care in the past year were associated with being unaware after adjustment. Among women, being of Mexican American or other Hispanic descent, having a family history of diabetes, receiving routine health care other than at a doctor’s office, and receiving no health care in the past year were associated with being unaware after adjustment.

Overall, approximately one-third of people with diabetes were undiagnosed/unaware of it. Non-Hispanic Asians and Hispanics of non–Mexican American descent were more likely to be unaware in unadjusted models but not after adjustment. In adjusted models, those with a family history of diabetes and those who had been hospitalized in the past year were less likely to be unaware, while those who received no health care in the past year were more likely to be unaware. Results were generally consistent when stratified by sex except that Mexican American and other Hispanic women were more likely to be unaware of their diabetes.

Some participants may have been misclassified, as a repeat measurement is recommended by the American Diabetes Association after a single positive test based on A1C, fasting plasma glucose, or 2-h plasma glucose; however, the NHANES only includes one study visit. Also, since participants self-reported many of the variables in our analysis, there may be inaccuracies.

Funding. This work was supported by National Institute of Diabetes and Digestive and Kidney Diseases contract GS10F0381L.

Duality of Interest. No potential conflicts of interest relevant to this article were reported.

Author Contributions. A.M. and C.C.C. designed the study. A.M. conducted the statistical analysis and drafted the manuscript. S.C., M.L.A.-S., and C.C.C. guided the statistical analysis and critically revised the manuscript for important intellectual content. All authors approved the final manuscript. A.M. and C.C.C are the guarantors of this work and, as such, had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the National Institute of Diabetes and Digestive and Kidney Diseases or the Centers for Disease Control and Prevention.

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