Glucose Tolerance Test
Diabetes Mellitus
Dr. David Gee
FCSN 442 - Nutrition Assessment Laboratory
Prevalence
2006
20.8 million Americans
– 7% population
 9.6% adults over 20 years
 21% adults over 60 years
 30% undiagnosed
– 6.2 million undiagnosed
 41 million with ‘pre-diabetes’

Implications of the Diabetes
Control and Complications Trial
Diabetes Care 25:S25-S27, 2002

Conventional Treatment vs Intensive Treatment
– IT had lower HA1C and FBG


Average 7 year follow up
Measured outcomes:
– Retinopathy, nephropathy, neuropathy

Results:
– 60% reduction in risk in intensive treatment group
Report of the Expert
Committee on the Diagnosis
and Classification of
Diabetes Mellitus
Diabetes Care 28:S4-S36, 2005
See at
Diabetes.org
For health professionals
2005 clinical practice recommendations
Criteria for testing for DM in
assymptomatic, undiagnosed patients
>
45 yrs, every 3 yrs (if normal)
 < 45 yrs, every 3 yrs if:
– BMI > 25 and any of the following
1st degree relative with DM
 Blacks, Hispanic, Native American, Asian American
 Habitually inactive
 Hx Gestational Diabetes or baby > 9 lbs
 History of vascular disease

Criteria for testing for DM in
assymptomatic, undiagnosed
patients
 < 45 yrs, every 3 yrs if: (cont.)
– Hypertension (>140/90)
– HDL < 35 mg/dl
– TG > 250 mg/dl
– previous Dx of impaired glucose
tolerance or impaired fasting glucose
Testing of children for Type 2
Diabetes

Criteria
– Overweight (BMI >85th percentile for age and sex,
weight for height >85th percentile, or weight >120% of
ideal for height)
– Plus any two of the following risk factors



Family history of Type 2 DM, 1o or 2o
Native American, black, asian, latino
Signs of insulin resistance (acanthosis nigricans, hypertension,
dyslipidemia)
– Age of initiation: 10 yrs or onset of puberty
– Frequency – every two years
– Test: FBG test preferred
Acanthosis nigricans
Fasting Blood Glucose
>
8 hr fast
 DM if FBG > 126 mg/dl (7.0mM)
– on 2 occasions
 Pre-Diabetes
– Impaired fasting glucose (IFG)
– if : 110 - 125 mg/dl
Casual Plasma Glucose
Casual is defined as any time of day without
regard to time since last meal
 > 200 mg/dl (11.1mM) plus

– Symptoms of diabetes


Polyuria, polydipsea, unexplained weight loss
Confirm on subsequent visit with fasting
blood glucose or oral glucose tolerance test
Glucose Tolerance Testing

for
– adults with impaired FBG
– during pregnancy if at risk

Procedure
– Following 8 hour fast
– Glucose dose = 1.75g/kg IBW
 Maximum 75 g dose (BW<43kg, 94lbs)
 25 g/dl glucose test solution
 Test at 2 hours
Diagnostic Criteria
 DM
if [glu] > 200 mg/dl at 2 hours
 IGT if [glu] >140 - 199 at 2 hours
 normal if [glu] < 140 mg/dl
 IGT and IFT recently termed “prediabetic”
Hemoglobin A1c
glycated hemoglobin

Average lifespan of red blood cells
– ~ 120 days (4 months)

Glycosylation of blood proteins in
proportion to blood glucose concentration
– Normal: 5%
– Goal for diabetics: < 7%