Ageing and associations of fasting plasma glucose and 2h plasma glucose with HbA1C in apparently healthy population. “FIN-D2D” study

Objective In this FIN-D2D cross-sectional survey the relationship of age with HbA1c and fasting and 2h glucose in the oral glucose tolerance test (OGTT) was explored in apparently randomly selected healthy population. Patients and methods The glycaemic parameters were measured in 1344 men and 1482 women (aged 45–74 years), and among them we excluded all subjects with known diabetes, hypertension or dyslipidaemia. The final analyses for HbA1c and the ratios of fasting glucose/HbA1c and 2h glucose/HbA1c included 649 men and 804 women. Results Mean age was 57 years and BMI 26.1kg/m2 for both genders. HbA1c increased in both genders with age (p <0.001). For a particular fasting glucose level HbA1c level was higher in older age groups (p <0.001 for linearity). By contrast, a particular 2h plasma glucose value in OGTT implied significantly lower HbA1c in the elderly (p <0.001 for linearity). Conclusion In apparently healthy population, screened with OGTT, in older individuals compared with younger ones a particular HbA1c value implies slightly lower fasting glucose, but relatively higher 2h glucose. These results need to be verified in different populations. The effects of age on relation between HbA1c and plasma glucose should be taken into account in classifying people into different dysglycaemia categories.