Effects of Age and Sex on Estimated Diabetes Prevalence Using Different Diagnostic Criteria: The Tromsø OGTT Study

Abstract

HbA(1c) 6.5% has recently been recommended as an alternative diagnostic criterion for diabetes. The aims of the study were to evaluate the effects of age, sex, and other factors on prevalence of diabetes and to compare risk profiles of subjects with diabetes when defined by HbA(1c) and glucose criteria. Subjects were recruited among participants in the longitudinal population-based Tromsø Study. HbA(1c), fasting plasma glucose, and 2-hour plasma glucose were measured in 3,476 subjects. In total, 294 subjects met one or more of the diagnostic criteria for diabetes; 95 met the HbA(1c) criterion only, 130 met the glucose criteria only, and 69 met both. Among subjects with diabetes detected by glucose criteria (regardless of HbA(1c)), isolated raised 2-hour plasma glucose was more common in subjects aged ≥ 60 years as compared to younger subjects and in elderly women as compared to elderly men. Subjects with diabetes detected by glucose criteria only had worse cardiometabolic risk profiles than those detected by HbA(1c) only. In conclusion, the current HbA(1c) and glucose criteria defined different subjects with diabetes with only modest overlap. Among a substantial proportion of elderly subjects, and especially elderly women, the 2-hour plasma glucose was the only abnormal value.

Figure 1

Diabetes prevalence by different diagnostic criteria. Venn diagrams illustrating prevalence of diabetes (%) defined by OGTT criteria (FPG and isolated raised 2hPG) and HbA_1c in (a) men aged < 60 years; (b) men aged ≥ 60 years; (c) women aged < 60 years; (d) women ≥ 60 years. The Tromsø OGTT Study.

Figure 2

Distribution of FPG and 2hPG values in relation to HbA_1c. Scatterplots illustrating the distribution of (a) FPG and (b) 2hPG values in relation to HbA_1c in subjects aged < 60 years and subjects aged ≥ 60 years. Stippled lines show cut-off points for diabetes. The Tromsø OGTT Study.