Patients with fasting plasma glucose levels of 100 to 125 mg/dL are considered to have "impaired fasting glucose" because they are at increased risk for eventually developing type 2 diabetes. In this study, Israeli researchers sought to determine whether a gradient of risk exists even among people with normal fasting glucose levels.
The study included 13,163 male military personnel (age, 26-45 years) with baseline fasting plasma glucose levels in the normal range (<100 mg/dL). During an average follow-up of 5.7 years, 208 men developed type 2 diabetes. The risk for diabetes increased progressively across quintiles of baseline fasting glucose: For example, the risk ranged from 0.8% among men whose baseline fasting glucose was in the lowest quintile (50–81 mg/dL) to 2.8% among those whose baseline fasting glucose was in the highest quintile (95–99 mg/dL). Even in a multivariate analysis that adjusted for potentially confounding variables such as body-mass index and family history, fasting glucose in the upper end of the normal range was associated independently with an increased risk for diabetes. Nevertheless, obesity did augment the risk.
These results demonstrate a continuum of risk for developing type 2 diabetes, even for patients whose fasting plasma glucose levels fall within the so-called normal range. The findings could serve as an incentive for patients with fasting glucose levels in the 90s to lose weight and increase exercise.
Reference:
Tirosh A et al. Normal fasting plasma glucose levels and type 2 diabetes in young men. N Engl J Med 2005 Oct 6; 353:1454-62.