Obstructive sleep apnea in young lean men: impact on insulin sensitivity and secretion

To assess whether the presence of obstructive sleep apnea (OSA) affects glucose metabolism in young, lean individuals who are healthy and free of cardiometabolic disease.

In a prospective design, 52 healthy men (age 18-30 years; BMI 18-25 kg/m(2)) underwent laboratory polysomnogram followed by a morning oral glucose tolerance test (OGTT). We stratified all subjects according to the presence or absence of ethnicity-based diabetes risk and family history of diabetes. We then used a frequency-matching approach and randomly selected individuals without OSA, yielding a total of 20 control men without OSA and 12 men with OSA. Indices of glucose tolerance, insulin sensitivity, and insulin secretion (early phase and total) were compared between men with OSA and control subjects. The incremental areas under the glucose (incAUC(glu)) and insulin (incAUC(ins)) curves were calculated using the trapezoidal method from 0 to 120 min during the OGTT.

Men with OSA and control subjects were similar in terms of age, BMI, ethnicity-based diabetes risk, family history of diabetes, and level of exercise. Both groups had normal systolic and diastolic blood pressure and fasting lipid levels. After ingestion of a glucose load, men with OSA had 27% lower insulin sensitivity (estimated by Matsuda index) and 37% higher total insulin secretion (incAUC(ins)) than the control subjects, despite comparable glucose levels (incAUC(glu)).

In young, lean, and healthy men who are free of cardiometabolic disease, the presence of OSA is associated with insulin resistance and a compensatory rise in insulin secretion to maintain normal glucose tolerance. Thus, OSA may increase the risk of type 2 diabetes independently of traditional cardiometabolic risk factors.