Ageing and associations of fasting plasma glucose and 2 h plasma glucose with HbA(1C) in apparently healthy population. "FIN-D2D" study

Abstract

Objective: In this FIN-D2D cross-sectional survey the relationship of age with HbA(1c) 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 HbA(1c) and the ratios of fasting glucose/HbA(1c) and 2h glucose/HbA(1c) included 649 men and 804 women.

Results: Mean age was 57 years and BMI 26.1kg/m(2) for both genders. HbA(1c) increased in both genders with age (p<0.001). For a particular fasting glucose level HbA(1c) 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 HbA(1c) 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 HbA(1c) 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 HbA(1c) and plasma glucose should be taken into account in classifying people into different dysglycaemia categories.