Post-challenge blood glucose concentration and stroke mortality rates in non-diabetic men in London: 38-year follow-up of the original Whitehall prospective cohort study

AIMS/HYPOTHESIS: While individuals with diabetes have a raised risk of stroke, it is unclear whether hyperglycaemia in non-diabetic populations is related to the development of this disease. METHODS: In this prospective cohort study of 19,019 men, capillary blood was drawn 2 h after consumption of a glucose preparation equivalent to 50 g of anhydrous dextrose. Study participants were then followed for mortality for a maximum of 38 years. RESULTS: During follow-up of 18,406 non-diabetic men, 13,116 deaths occurred (1,189 by stroke). Plots of stroke mortality rates versus blood glucose identified an upward inflection in risk of death from stroke at about 4.6 mmol/l. This upward inflection in risk could be adequately described using a single linear term above this threshold. A 1 mmol/l increase in blood glucose after this point was associated with a 27% increase in risk of death from stroke (hazard ratio 1.27, 95% CI 1.14–1.42). This increase in risk was partially attenuated by adjustment for covariates (1.17, 1.04–1.31) but remained statistically significant at conventional levels. Similar observations were made when all-cause mortality was the outcome of interest, although the magnitude of the association with blood glucose was somewhat lower. CONCLUSIONS/INTERPRETATION: An incremental elevation in stroke mortality rates occurs with increasing post-challenge blood glucose.