Norhammar et al. (1) recently conducted a case-control study to determine the relationship among previously undetected dysglycemia (prediabetes and diabetes), myocardial infarction (MI), and periodontitis. In this study, after excluding individuals with established diabetes, all subjects were examined with an oral glucose tolerance test and were categorized as having a glucose status of normal glucose tolerance (NGT), impaired glucose tolerance (IGT), or diabetes by their 2-h postload glucose level. As detailed in Supplementary Table 1 of the article (1), participants who had a fasting plasma glucose (FPG) of <7.0 mmol/L and a 2-h glucose (2h-PG) of <7.8 mmol/L were categorized as having NGT, and the authors declared that this categorization was made according to the World Health Organization (WHO) definition. But as a matter of fact, in the 1999 WHO definition, NGT referred to a normoglycemia state and was defined as an FPG of <6.1 mmol/L and a 2h-PG of <7.8 mmol/L (as shown in Fig. 2 of the 1999 report of the WHO Consultation [2]), while impaired fasting glucose (IFG), with an FPG of ≥6.1 to <7.0 mmol/L and a 2h-PG of <7.8 mmol/L, belongs to prediabetes instead of NGT. IFG and/or IGT, together with diabetes, are classified as hyperglycemia or dysglycemia according to the WHO definitions (2,3). IFG and IGT, known as prediabetes, represent a state of disordered glucose metabolism intermediate between normoglycemia and diabetes. Hence, the role of IFG as an important risk factor for diabetes should not be overlooked, and IFG should not be classified in the NGT group when exploring the association between dysglycemia and MI. We should know how many participants in this study had IFG and whether these participants were equally distributed in the control and patient cohorts. Further analysis of the relationship between dysglycemia and MI through adjusting the classification of glucose status is expected.
Article Information
Duality of Interest. No potential conflicts of interest relevant to this article were reported.
