One-hour post-load plasma glucose level predicts future type 2 diabetes in a community-based study of Hong Kong Chinese workforce.

ABSTRACT

BACKGROUND: We compared performance of high 1-hour PG level, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) in predicting type 2 diabetes in a longitudinal community-based cohort of Hong Kong Chinese. METHODS: Between 2001 and 2003, 472 adults aged 18-55 years without diabetes underwent 75-gram oral glucose tolerance test (OGTT). Between 2012 and 2014, progression to diabetes was ascertained by reviewing medical records or repeating OGTT and HbA1c. We defined high 1-hour PG as PG ≥ 8.6 mmol/L at 1-hour. RESULTS: In this cohort, 23.5% had normal glucose tolerance and high 1-hour PG, 10.0% had isolated IGT, 4.2% had isolated IFG. Over 12-year follow-up, 9.3% developed type 2 diabetes. In logistic regression, high 1-hour PG was associated with progression to type 2 diabetes with adjusted odds ratio (95% CI) of 4.20 (1.60, 12.40), independent of IFG, IGT and other clinical variables. Areas under ROC (95% CI) for type 2 diabetes were similar between 1-hour (0.84 [0.78, 0.89], 2-hour (0.79 [0.72, 0.86]) and fasting PG (0.79 [0.71, 0.86]). CONCLUSION: High 1-hour PG identified young Chinese with 5-fold increased risk of type 2 diabetes independent of other intermediate hyperglycaemia status and clinical factors. 1-hour PG is similar to fasting and 2-hour PG in predicting type 2 diabetes.