Assessment of fasting plasma glucose, insulin, insulin resistance and glycated haemoglobin as markers of glycemic control in apparently healthy older adults in Nnewi

Abstract

: Biochemical changes in glycemic indices have been linked to aging, and many individuals have asymptomatic hyperglycemia as they get older. This leads to metabolic dysregulation, which heightens vulnerability to a number of age-related chronic conditions, such as diabetes mellitus. : This cross-sectional study assessed the levels of fasting plasma glucose, insulin, insulin resistance and glycated haemoglobin as markers of glycemic control in apparently healthy older adults in Nnewi. A total of 144 participants were involved in this study: 72 older persons and 72 control subjects. The older adults were aged 45 to 75; while the control group was composed of individuals aged 18 to 30.  Six milliliters (6 ml) of fasting venous blood samples were collected from each participant for the determination of insulin (INS), glycated haemoglobin (HbA1c), and plasma glucose (FPG) levels. Enzyme-linked immunosorbent assay was used to evaluate INS, resin ion-exchange was used to estimate HbA1c, and glucose oxidase peroxidase was used to determine FPG. The Homeostasis Model Assessment Index (HOMA-IR) was used to calculate insulin resistance. : The mean FPG, HbA1c, INS and HOMA-IR were significantly higher in the older adults compared to control subjects respectively (p<0.05). Also, the mean FPG, HbA1c, INS and HOMA-IR were significantly higher in the older adult males and females compared to the control male and female subjects respectively (p<0.05). There was significant moderate positive correlation between the level of FBS Vs HbA1c (r=0.484, P-value = 0.000) and strong positive correlation between the level of Insulin Vs HOMA-IR (r=0.980, P-value = 0.000) in the control group. Also, strong significant positive correlations were observed between FPG and HbA1c (r=0.704, P-value = 0.000), FPG and HOMA-IR (r=0.778, P-value = 0.000), Insulin and HOMA-IR (r=0.778, P-value = 0.000) with a moderate significant positive correlation found between HbA1c Vs HOMA-IR (r=0.557, P-value = 0.000) in the older adults. This study showed that glycemic indices tend to become altered with advancing in age.