After initial screening by telephone, requisitions for hemoglobin A1c testing were mailed to potentially eligible individuals. Those with a screening hemoglobin A1c value of 6.6% to 9.9% were invited for in-person assessment, where informed consent was obtained, followed by a history and physical examination. Participants returned on a separate day for maximal exercise stress testing with electroencephalographic monitoring by using a ramp protocol on a treadmill. Persons with abnormalities on this test were allowed to proceed in the trial only if cleared by a cardiologist.
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