Factors determining normalization of glucose intolerance in middle-aged Swedish men and women: a 8-10-year follow-up

To examine factors in middle-aged Swedish men and women predicting the conversion from a state of abnormal glucose regulation to normal glucose tolerance (NGT) after 8-10 years. At baseline 3128 men and 4821 women, aged 35-56 years, without previously diagnosed diabetes underwent an oral glucose tolerance test and completed a questionnaire. At follow-up, 2383 men and 3329 women were re-examined. The study group consisted of 156 men and 124 women with impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or both at baseline. The rate of reversal to NGT from IFG or IGT was similar regardless of gender. In participants having IFG or IGT, reversal to NGT was predicted by low fasting and 2-h insulin, homeostasis model assessment of insulin resistance and of pancreatic beta cell function, body mass index and waist circumference without differences between gender and baseline glucose tolerance group. Low 2-h glucose, however, predicted reversal to NGT in men with IFG at baseline, but not in men with IGT at baseline, or in women with either IFG or IGT at baseline. Men reverting to NGT had higher coffee consumption and women had higher baseline leisure-time physical activity. In multiple logistic regression, including all participants, low fasting and 2-h glucose remained independent predictors of reverting to NGT. Factors predicting reversal to NGT were measures correlated with low insulin resistance, but also lower insulin secretion, perhaps indicating a lower pancreatic beta cell workload in those who reverted. In men, but not in women, low 2-h glucose was of predictive value.