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

Diabet Med. 2002 Mar;19(3):254-8. doi: 10.1046/j.1464-5491.2002.00644.x.

Abstract

Aims: To examine the influence of age on glucose homeostasis in a population of healthy, non-diabetic hospital personnel.

Methods: One hundred and twenty female and 71 male non-diabetic individuals (fasting plasma glucose < 7.0 mmol/l) were fasted overnight prior to blood sampling. Glycated haemoglobin (HbA1c), fasting plasma glucose (FPG) and fasting plasma insulin (FPI) were measured using a BioRad Diamat automated HPLC, a Hitachi 747 analyser and a sensitive in-house radioimmunoassay, respectively. Mathematical modelling of the fasting glucose and insulin pairs (homeostasis model assessment (HOMA)) generated indices of pancreatic beta cell function, HOMA-B and tissue insulin sensitivity HOMA-S.

Results: Spearman rank correlation analysis showed that in the whole group there was a significant negative correlation between age and HOMA-B (rs = -0.218, P = 0.0022) and a significant positive correlation between age and both HbA1c (rs = 0.307, P = 0.0001) and FPG (rs = 0.26, P = 0.0003). There was no correlation between age and either FPI (rs = -0.08, P = 0.266) or HOMA-S (rs = 0.024, P = 0.75). Analysis by gender showed the above associations to be present in the females (rs = -0.243, P = 0.0076; rs = 0.304, P = 0.0007; rs = 0.32, P = 0.0004 for age vs. HOMA-B, HbA1c, and FPG, respectively). Again there was no correlation of age with FPI or insulin sensitivity. In the males there was a significant correlation of HbA1c with age (rs = 0.35, P = 0.002), but no significant correlation of age with any of the other parameters.

Conclusions: Glycaemic control deteriorates with age in healthy, non-diabetic individuals. Age-related rises in FPG and haemoglobin A1c result from a small but steady decline in pancreatic beta cell function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aging / physiology*
  • Blood Glucose / metabolism*
  • Cross-Sectional Studies
  • Fasting
  • Female
  • Glycated Hemoglobin A / metabolism*
  • Humans
  • Insulin / blood
  • Insulin / metabolism*
  • Insulin Secretion
  • Islets of Langerhans / growth & development
  • Islets of Langerhans / physiology*
  • Male
  • Reference Values
  • Regression Analysis

Substances

  • Blood Glucose
  • Glycated Hemoglobin A
  • Insulin