Lowering the Criterion for Impaired Fasting Glucose

Abstract

OBJECTIVE -To determine the effect of lowering the fasting plasma glucose (FPG) criterion for impaired fasting glucose (IFG) on the prevalence of IFG, the risks of diabetes, and cardiovascular disease (CVD) associated with IFG. RESEARCH DESIGN AND METHODS-Three studies were used: 1) the 1998 National Health Survey (NHS98), a randomly selected cross-sectional sample of 4,723 subjects; 2) the Singapore Impaired Glucose Tolerance (IGT) Follow-up Study, a cohort study comprising 295 IGT and 292 normal glucose tolerance subjects (frequency matched for age, sex, and ethnic group) followed up from 1992 to 2000; and 3) the Singapore CVD Cohort Study, comprising 5,920 subjects from three cross-sectional studies in whom the first ischemic heart disease (IHD) event was identified through linkage to registry databases. Risk of diabetes (Singapore IGT Follow-up study) was estimated using logistic regression adjusted for age, sex, and ethnicity. Risk of IHD (Singapore CVD cohort) was estimated using stratified (by study, from which data were derived) Cox's proportional hazards models adjusted for age, sex, and ethnicity.RESULTS -Lowering the criterion for diagnosing IFG to 5.6 mmol/l increased the prevalence of IFG from 9.5 to 32.3% in the NHS98. The lower cutoff identified more subjects at risk of diabetes and IHD, but the relative risk was lower than that for IGT.CONCLUSIONS -Greater efforts to identify those with IGT, or a group at similar risk of diabetes and CVD, may be a more efficient public health measure than lowering the FPG criterion for diagnosing IFG. Diabetes Care 27:1728 -1734, 2004T he American Diabetes Association had previously recommended (1) the recognition of impaired fasting glucose (IFG) as a category of glucose tolerance analogous to impaired glucose tolerance (IGT). It was recommended that IFG be diagnosed in those with fasting plasma glucose (FPG) between 6.1 and 6.9 mmol/l. Since then, many analyses have examined the equivalence of FPG and 2-h postchallenge glucose (2-h PG) in predicting both diabetes and cardiovascular disease (CVD). Several key findings have emerged from these studies. First, the association between IGT and CVD events and mortality is stronger than that for IFG (2,3). Second, although IFG and IGT identify some of the same individuals, the degree of overlap is variable (4,5). As a consequence of the recommendations to use FPG rather than 2-h PG for the diagnosis of diabetes, many subjects with IGT, who are at risk of future CVD events, would not be identified.On the basis of the aforementioned findings, the American Diabetes Association has recently recommended (6) that the lower limit for the diagnosis of IFG be changed from 6.1 to 5.6 mmol/l. However, the need for this change has been questioned by others (7,8). Singapore is a small country in Asia with a high prevalence of diabetes and IGT. As in Europe and the U.S., we have found that IFG and IGT often identify different individuals. Only 26% of subjects with IGT had IFG (as defined by the older criteria of FPG 6.1-6.9 mmol/l),...

A report on the diagnosis of intermediate hyperglycemia in Korea: A pooled analysis of four community-based cohort studies

“…We also observed very poor agreement between the fasting and 2-h PG criteria with the new definition of IFG. Tai et al stressed that lowering the criterion for IFG from 6.1 to 5.6 mmol/L did not improve the predictive value of IFG for development of diabetes and ischemic heart disease in a Singaporean population, by showing with receiver operating characteristics analysis that IGT is associated with a greater risk of both diabetes and ischemic heart disease, even when the FPG corresponding to IGT was <5.6 mmol/L [30]. In this study, we found that there was a significant difference in the obesity index and metabolic profiles between individuals with stage 1 IFG (FPG 5.6-6.1 mmol/ L) and stage 2 IFG (FPG 6.1-7.0 mmol/L) ( Table 3).…”

Periodontal disease might be associated even with impaired fasting glucose

“…19 Elevated fasting plasma glucose level (≥100 mg/dL) in young adults may predict type 2 diabetes in older age, more than fasting plasma glucose level of <100 mg/ dL. 20,21 The present results revealed a higher occurrence of alveolar bone loss in subjects with elevated (although still considered non-diabetic) fasting glucose level of ≥100 mg/dL. Thus, periodontal disease might serve as a predictor for future DM, or as a possible causative factor for impaired glucose balance and the development of DM.…”

Cardiometabolic Risk in Impaired Fasting Glucose and Impaired Glucose Tolerance

“…The change has been controversial (9,38 -42). Population-based data from the U.S. and other countries indicate that the prevalence of IFG increased two-to fourfold upon application of the new criteria (9, 12,39,43,44), with the largest increases in IFG in younger age-groups (39). A recent report from the National Health and Nutrition Examination Survey 1999 -2002 estimated that 26 million U.S. adults have IFG using the lower cut *Fasting glucose Ͻ5.6 mmol/l and postchallenge glucose Ͻ7.8 mmol/l.…”