Postchallenge glucose rises with increasing age even when glucose tolerance is normal.
AIMS: Ageing increases the likelihood of developing diabetes, with associated cardiovascular disease. In a cross-sectional study, we sought to determine whether age is associated with an increase in glucose concentrations 1 h after an oral glucose challenge (1-h OGTT), even when glucose tolerance is normal (NGT). METHODS: Among subjects in the NHANES II database, 2591 subjects with NGT and documented 1-h OGTT glucose concentrations were studied. The relationship between age and 1-h OGTT glucose concentrations was assessed in a multivariable linear regression analysis. RESULTS: In a multivariable linear regression analysis, each 10-year increase in age conferred an additional 0.20 mmol/l increase in the 1-h OGTT glucose (P < 0.0001). Moreover, an interaction between age and gender was found such that 1-h OGTT glucose concentrations rose more rapidly with increasing age in men than in women. The impact of age on 1-h OGTT glucose was independent of both fasting and 2-h OGTT glucose concentrations. CONCLUSIONS: One-hour OGTT glucose concentrations rise significantly with age even in subjects with NGT. Further investigation is warranted to explore the pathophysiological significance of such age-related impairment of glucose handling, which might increase the risk of cardiovascular disease even when patients do not meet criteria for the diagnosis of diabetes or prediabetes.