medwireNews: A blood glucose level taken 1 hour after glucose loading better predicts future type 2 diabetes risk than the level taken at 2 hours, long-term study findings indicate.
Writing in Diabetes Care, Manan Pareek (Harvard Medical School, Boston, Massachusetts, USA) and co-authors say their results “highlight the potential benefit of targeting individuals with an elevated 1-[hour] blood glucose level and provide a strong rationale for an interventional study in which subjects are selected based on this abnormality.”
They add: “Should preventive efforts prove beneficial in this relatively large group, it would become prudent to consider 1-[hour] blood glucose as a replacement for 2-[hour] blood glucose.”
The prospective population-based cohort study included 4867 men, born between 1921 and 1949, who underwent an oral glucose tolerance test at a median age of 48 years as part of the Malmö Preventive Project.
At 39 years of follow-up, the cumulative type 2 diabetes incidence was 13% overall, corresponding to an incidence rate of 4.8 cases per 1000 person–years.
The cumulative incidence among individuals with a normal glucose level at both 1- and 2-hours (<7.8 mmol/L and <8.6 mmol/L, respectively, n=3139) was 8%. It was 22% among those with an elevated level at 1 hour only (n=1564), 13% among those with an elevated level at 2 hours only (n=32), and 23% among those with an elevated level at both timepoints (n=132).
After adjustment for age, BMI, impaired fasting glucose, triglycerides, and family history of diabetes, individuals with an elevated 1-hour glucose level despite a normal 2-hour level had a significant 2.9-fold increased risk for incident diabetes at 39 years compared with individuals with a normal glucose level at both timepoints
The risk increase was a significant 2.8-fold for individuals with raised glucose at both timepoints.
By contrast, individuals with an increased level at 2 hours but a normal level at 1 hour (n=32) had no significantly increased risk for type 2 diabetes compared with those with normal measurements at both timepoints.
The researchers also found that the presence of an elevated 1-hour blood glucose level was associated with significantly greater discriminative ability than impaired glucose tolerance based on 2-hour blood glucose, as well as a significantly improved reclassification of individuals with prediabetes as defined traditionally by fasting blood glucose.
Similar results were observed when the team looked at all-cause mortality; the adjusted risk for death during follow-up was increased among individuals with a raised 1-hour glucose level despite a normal 2-hour level, at a hazard ratio of 1.29, but was not significantly increased among those whose blood glucose was elevated at 2 hours, but not at 1 hour.
Elevated 1-hour glucose levels were also associated with an increased risk for retinopathy and peripheral vascular complications.
By Laura Cowen
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