Physical Activity and Improvement of Glycaemia in Pre-diabetes by Different Diagnostic Criteria

CONTEXT: The effects of physical activity (PA) on improvement of glycaemia may differ between pre-diabetic individuals defined by OGTT versus HbA1c. OBJECTIVE: We studied the association between PA and improvement of glycaemia in individuals with pre-diabetes defined by glucose versus HbA1c criteria. DESIGN, SETTING AND PARTICIPANTS: From the Whitehall II study, 957 participants with pre-diabetes defined by isolated impaired fasting glucose (i-IFG), isolated impaired glucose tolerance (IGT) or both (IFG+IGT), and 457 with pre-diabetes defined by HbA1c were included. MAIN OUTCOME MEASURES: The associations of PA with concomitant changes in glucose-related outcomes during 5-years of follow-up were analysed. A recursive partitioning analysis was performed to study heterogeneity in the association between baseline PA and the probability of reversion to normoglycaemia. RESULTS: After 5-years of follow-up, 405 (42%) individuals with glucose-defined pre-diabetes reverted to NGT. A 5-year increase in moderate-to-vigorous-intensity PA was associated with improvements in insulin sensitivity and beta-cell function, but PA was not generally associated with reversion to NGT. Only among women ≥50 years with i-IFG or i-IGT, higher amounts of PA were associated with higher probability of reversion to NGT. In HbA1c-defined pre-diabetes, only 20 individuals (4.4%) reverted to normoglycaemia, and PA was not associated with improvement in glycaemic markers. CONCLUSIONS: PA may be particularly important for reversion to normoglycaemia in older women with i-IFG or i-IGT. Individuals with pre-diabetes identified by HbA1c have a low probability of reversion to normoglycaemia, and their changes in glycaemia are not related to PA