Reproducibility of the Oral Glucose Tolerance Test

McDonald, Glen W.; Fisher, Gail F.; Burnham, C. E.

doi:10.2337/diab.14.8.473

Cited by 209 publications

(87 citation statements)

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“…It is likely that the changes are specific since: (1) the frequency of impaired glucose tolerance in twins who remain non-diabetic is high (11% ), considerably higher than could be expected for a normal population of this age (about 2%) [20] and (2) impaired glucose tolerance was only found in twins within five years of the diagnosis of the index twin. This clustering of changes in glucose tolerance around the time of diagnosis of the index twin suggests that the changes are not a nonspecific consequence of the potential variability in glucose tolerance [21]. Thus, some twins who remain non-diabetic showed both immune [19] and metabolic changes around the time of diagnosis of diabetes in the index twin but not thereafter.…”

Section: Discussionmentioning

confidence: 88%

“…As required by the criteria of entry all the twins were within five years of the diagnosis of their index twin (median 7 months range 1 to 24). They were compared with seven control subjects of similar age (15.6 + 4.0 years; range 10-24), BMI (20.2 + 3.4 kg/m2; range [16][17][18][19][20][21][22][23][24][25] and sex (four male). The remaining six twins are still not diabetic seven to 10 years from the diagnosis of the index twin; their mean age at testing was 16.9 + 3.9 years (range 14-24), BMI of 22.6 • 3.7 kg/m 2 (range 20-29), four were male.…”

Section: Studymentioning

confidence: 99%

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Impaired glucose tolerance precedes but does not predict insulin-dependent diabetes mellitus: a study of identical twins

et al. 1990

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Summary. Non-diabetic identical twins of insulin-dependent diabetic patients were studied within five years of the diagnosis of their index twin in order to determine whether changes in intermediary metabolism precede the onset of insulin-dependent diabetes mellitus. Two studies were performed: a cross-sectional study of 12 non-diabetic twins and a prospective study of a separate group of 41 non-diabetic twins. Of the 12 twins tested in the cross-sectional study six developed insulin-dependent diabetes and six did not; the six who developed diabetes were given an oral glucose load a mean of 10 months before diagnosis; they then had normal fasting blood glucose levels but worse glucose tolerance than control subjects (120 min post-load (mean + SD) blood glucose 8.5 _+ 3.5 vs 4.9 + 0.9 mmol/1 respectively, p < 0.05). However, blood lactate, pyruvate, alanine, glycerol, 3-hydroxybutyrate and serum insulin levels were similar. In contrast, the six twins in this cross-sectional study who did not develop diabetes and are now unlikely to do so, as a group, had no significant changes compared with the control subjects though one had impaired glucose tolerance. To determine the predictire value of impaired glucose tolerance a separate group of 41 non-diabetic twins was studied prospectively for 8 to 22 years having a total of 147 glucose tolerance tests in' this period; in this group six developed diabetes. Eight of the 41 had impaired glucose tolerance; impaired glucose tolerance was found in four of the six who developed diabetes as compared with only four of the 35 who did not (p < 0.01). Impaired glucose tolerance in these non-diabetic identical twins had a positive predictive value of 33% for developing diabetes. The four twins with impaired glucose tolerance who remain nondiabetic now have normal glucose tolerance. We conclude that impaired glucose tolerance may precede the onset of insulin-dependent diabetes mellitus by many months but the change does not specifically predict the disease even in identical twins of diabetic patients. These observations are consistent with the possibility that in some twins the disease process can occur yet remit without leading to diabetes.

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Section: Discussionmentioning

confidence: 88%

Section: Studymentioning

confidence: 99%

Impaired glucose tolerance precedes but does not predict insulin-dependent diabetes mellitus: a study of identical twins

et al. 1990

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“…One problem with IGT is the variability of the oral glucose tolerance test [2]. Subjects who have had IGT at one examination and have been retested within 3 months changed their classification status in up to 75 % of cases [3].…”

Section: Variability Of Igtmentioning

confidence: 99%

Impaired glucose tolerance is it relevant for cardiovascular disease?

Haffner

1997

Diabetologia

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The question of whether impaired glucose tolerance (IGT) is relevant to cardiovascular disease, is a subset of the more general question of whether glucose levels are related to cardiovascular disease in non-diabetic subjects. The World Health Organization (WHO) criteria for IGT are a plasma glucose level less than 7.8 mmol and a 2-h post glucose load (75 g) value of 7.8-10.9 mmol [1]. Variability of IGTOne problem with IGT is the variability of the oral glucose tolerance test [2]. Subjects who have had IGT at one examination and have been retested within 3 months changed their classification status in up to 75 % of cases [3]. The concept of IGT has been challenged by Yudkin et al. [4] and Stern et al. [5]. In the latter commentary, it was suggested that the category IGT comprised three groups: a) stable persistent IGT; b) subjects who have IGT but are undergoing rapid conversion to non-insulin-dependent diabetes (NIDDM); and c) subjects who actually had normal glucose tolerance (NGT) but on that particular day had high glucose levels and were placed in the IGT category. In low-risk populations for NIDDM such as Europeans, the number of individuals with IGT in the third category would be particularly high. Given the possible problems with the category of IGT, it might seem surprising that IGT is a risk factor for anything, even for diabetes. However, in recent data from six populations (which include both high and low-risk populations for NIDDM), Edelstein et al. [6] have shown that IGT is a consistent predictor of NIDDM. IGT and cardiovascular factorsMany studies have shown that IGT is associated with increased cardiovascular risk factors. Burchfiel et al. [7] found that subjects with IGT had increased cardiovascular risk factors (decreased high density lipoprotein (HDL) cholesterol and increased triglyceride, blood pressure, and plasma insulin) intermediate between subjects with NGT and NIDDM. In a study of elderly subjects, Mykkä nen et al. [8] found that men and women with IGT had significantly higher total triglycerides, apolipoprotein B (apo B) and lower HDL cholesterol and apo A than men and women with NGT. In addition, women with IGT had significantly higher systolic blood pressure than women with NGT. Prevalence of coronary heart disease (CHD) in IGT subjectsIn elderly Finnish subjects [9], the prevalence of definite or probable myocardial infarction was not significantly different in either men or women with IGT compared to subjects with NGT. However, the prevalence of angina was higher in men with IGT than in men with NGT. No differences were seen in the prevalence of angina between women with NGT or IGT. In the San Luis Valley Study [10], the prevalence of overall CHD was increased approximately twofold in both non-Hispanic white men and women with IGT compared to subjects with NGT. However, the prevalence of overall CHD was very similar in Hispanic men and women with IGT and NGT.

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“…The OGTT is subject to considerable intra-individual variation [18, [49][50][51] and fasting plasma glucose appears preferable to 2-h plasma glucose in this respect. In a recent study of Dutch adults, in which the OGTT was repeated during a 2-6-week interval, the intra-individual coefficients of variation were 6.4 % for fasting glucose and 16.7 % for the 2-h plasma glucose [51].…”

Section: Comparison Of Measures Of Hyperglycaemiamentioning

confidence: 99%