Impaired glucose tolerance, but not impaired fasting glucose, is a risk factor for early-stage atherosclerosis.

Aims: The study aimed to investigate early-stage atherosclerosis in patients with impaired fasting glucose compared with patients with impaired glucose tolerance.

Methods: Body mass index, systolic blood pressure, fasting plasma glucose, lipid variables, ankle-brachial pressure index and brachial-ankle pulse wave velocity were measured in 2842 subjects from Takasaki city located approximately 100 km north of Tokyo in Japan. The subjects were divided into the following five groups based on a 75-g oral glucose tolerance test: (i) normal fasting plasma glucose/normal glucose tolerance group, (ii) impaired fasting glucose group, (iii) impaired glucose tolerance group, (iv) combined glucose intolerance group and (v) diabetic glucose intolerance group.

Results: In comparison with fasting plasma glucose levels (r = 0.269, P < 0.0001), 2-h post-challenge glucose levels were more closely correlated with pulse wave velocity values (r = 0.300, P < 0.0001). The groups with impaired glucose tolerance, combined glucose intolerance and diabetic glucose intolerance had significantly higher pulse wave velocity values compared with the groups with normal glucose tolerance and impaired fasting glucose. Multiple regression analyses showed an independent association of age, systolic blood pressures, total cholesterol, fasting and 2h plasma glucose with pulsewave velocityvalues. Furthermore, pulse wave velocity was not significantly correlated with fasting plasma glucose, but was correlated with increased 2h plasma glucose.

Conclusions: Groups with impaired glucose tolerance and combined glucose intolerance had significantly higher brachio-ankle pulse wave velocity values compared with the group with normal glucose tolerance. Although the group with impaired fasting glucose showed a marginal increase in pulse wave velocity values compared with the group with normal glucose tolerance, the difference was not significant. Thus impaired glucose tolerance, but not impaired fasting glucose, is a risk factor for early-stage atherosclerosis.