Table 1 Description of the National Health and Nutrition Examination Survey data set used for the study

Diagnosed diabetes

Answered "yes" to question "Have you ever been told by a doctor or health professionals that you had diabetes?"

Undiagnosed diabetes

Answered "no" to question "Have you ever been told by a doctor or health professionals that you had diabetes?"

AND

Fasting plasma glucose level ≥ 126 mg/dl

Pre-diabetes

Fasting plasma glucose level 100-125 mg/dl

No diabetes

Fasting plasma glucose level <100 mg/dl