HbA_1c local reference ranges: Effects of age, sex and ethnicity

Abstract

Objective: To determine a local HbA,, reference range. Design: Healthy volunteers recruited into an observational study. Subjects: 262 healthy volunteers. Subjects were excluded if known to be diabetic or on medication known to interfere with glucose levels or if random capillary blood glucose was > 10 mmoVL. Results: Reference range was mean 5.5% (+/-0.5). There were differences in ethnicity, sexand age. Ethnicity: Mean HbA,, in whites (n= 135) was 5.3% (+/-0.4), which was lower than for Indo-Asians (n= 127), which was 5.7% (+/-0.5): p=O. 00 1. Sex: In females (n=140) mean HbA,, was 5.4% (+/-0.45), which was lower than for males (n= 122) 5.6% (+/-0.5): p=O. 006. Age: For white males aged 20-44 the mean value was 5.1 % compared to a mean value of 5.6% in men >65 years. White females changed from 5.0% at a g e s 2 W 4 to 5.4% for>65years. Indo-Asian females changed from 5.3% at ages 20-44 to 5.7% in women >65 years. However, for lndo-Asian men aged 20-44 the mean value was 5.6% and remained at 5.6% above the age of 65years. Conclusion: Our local reference range for DCA 2000 measurement of HbA,, has now been established and is 5.5% (+/-0.5). Two standard deviations allow the normal range to rise to 6.5%. Significant (if small) differences were seen between sex, age and ethnicity. Districts, particularly those with non-white populations, should establish local reference ranges for measurement of glycated haemoglobin. This study shows that it is practical to do so. Practical Diabetes Int 1 999; 16(6): 21 1-21 4 Key words reference range, HbA , , , ethnicity 42 37 43 122 Total 95 87 82 262 I Male

Age‐related increase in haemoglobin A1c and fasting plasma glucose is accompanied by a decrease in β cell function without change in insulin sensitivity: evidence from a cross‐sectional study of hospital personnel

“…The present data confirm observations of gradual deterioration of short and long‐term indices of glycaemic control associated with advancing age in non‐diabetic subjects from hospital‐based populations [5–7] and in epidemiological studies in younger apparently healthy volunteers [3]. Our data are derived from comparatively young healthy volunteers with normal FPG.…”

“…There are conflicting reports concerning age and glycaemic control. A positive correlation of glycated haemoglobin with age has been found in normal subjects of both sexes in some studies [3,4] but not in others [5–7]. Similarly, there was a positive correlation of fasting plasma glucose (FPG) with age in some reports [3,5] but not in others [4,6,7].…”

Effect of ethnicity on HbA1c levels in individuals without diabetes: Systematic review and meta-analysis

“…Following the initial strategy, we identified 3,555 studies. After the examination of titles and abstracts, 61 studies were selected for a full text analysis and 12 studies met the inclusion criteria [ 19 , 20 , 22 , 24 , 25 , 34 – 40 ]. All manuscripts have provided sufficient data for quantitative analysis, totalizing data from 49,238 individuals.…”

Ethnic differences in glycated haemoglobin between white subjects and those of South Asian origin with normal glucose tolerance: Table 1

“…Black subjects also have higher HbA 1c levels compared with white subjects in those self-reporting as non-diabetic 14. HbA 1c in non-diabetic subjects has been reported as being higher in South Asians compared with white subjects 15 16. In one of these reports, non-diabetes was defined as a fasting blood glucose concentration of <7.8 mmol/l, and the higher HbA 1c in South Asians was explained by their higher fasting glucose concentrations 15.…”

“…In one of these reports, non-diabetes was defined as a fasting blood glucose concentration of <7.8 mmol/l, and the higher HbA 1c in South Asians was explained by their higher fasting glucose concentrations 15. In the other study, non-diabetes was defined as a random capillary blood glucose <10 mmol/l 16. As glucose tolerance was not defined by the recognised diagnostic gold standard of a 75 g oral glucose tolerance test (OGTT), it is possible and indeed probable that these studies included glucose intolerant subjects.…”