Physical activity and cause-specific mortality in men with Type 2 diabetes/impaired glucose tolerance: evidence from the Whitehall study.

AIMS

Given that studies of individuals with Type 2 diabetes or impaired glucose tolerance indicate that physical activity has a normalizing effect on several indices of coronary heart disease (CHD) risk-including body weight, blood pressure, blood lipids, and cardiorespiratory fitness-it is plausible that activity may reduce CHD incidence in this group in the long term. The aim of the present analysis was to explore this hypothesis using data from a prospective observational study.

METHODS

We examined the relation of two indices of physical activity-walking pace and leisure activity-to total mortality, CHD, and other cardiovascular diseases in a 25-year follow-up of 6408 male British Civil Servants who underwent an oral glucose tolerance test at study entry.

RESULTS

In 352 men who were identified as having Type 2 diabetes or impaired glucose tolerance (diabetes/IGT) at baseline, 215 had died at follow-up and, in 6056 normoglycaemics, 2550 deaths had occurred. The two indices of physical activity were inversely related to all-cause, CHD, and other cardiovascular disease mortality in both normoglycaemics and in men with diabetes/IGT. Although these associations were attenuated somewhat after statistical adjustment for a range of covariates, the majority held, suggesting an independent effect for physical activity. The gradient of the activity-mortality association was steeper in individuals with diabetes/IGT in comparison with the normoglycaemics, with the linear trend across activity levels for CHD risk differing markedly in the analyses of both walking pace (P-value for interaction test = 0.05) and leisure activity (P-value = 0.02).

CONCLUSIONS

The findings of the present analysis of men with Type 2 diabetes/IGT provide support for those from a small number of other studies of persons with Type 2 diabetes suggesting that this group may benefit from physical activity in terms of CHD risk reduction.