Fasting plasma glucose in non-diabetic elderly women predicts increased all-causes mortality and coronary heart disease risk

Aim: To confirm the hypothesis that upper normal plasma glucose levels in n on-diabetic subjects are independently predictive of mortality and cardiova scular disease (CVD). Methods: The study reports on 113 months' follow-up in a prospective study of CVD in the Australian elderly, The Dubbo Study. The cohort, first examin ed in 1988-89, consisted of 2805 men and women 60 years and older. Of the c ohort, 2419 (86%) were defined as non-diabetic. The prediction of outcomes by quartile of fasting plasma glucose was examined in a Cox proportional ha zards model, after linkage to hospital and death records. Results: All-causes mortality increased progressively across quartile of fa sting plasma glucose in both sexes, reaching statistical significance only in women. Coronary heart disease (CHD) incidence increased similarly, the i ncreases being proportionately greater in women. Ischaemic stroke did not s how a consistent gradient with fasting plasma glucose. After adjustment for age and other risk factors, all-causes mortality, CHD and ischaemic stroke incidence were not significantly related to plasma glucose in men. In wome n, all-causes mortality and CHD incidence showed a significant gradient wit h glucose quartile. Hazard Ratio (95% confidence intervals) for death in gl ucose Quartile IV(5.3-6.0 mmol/L) was 1.49 (1.03-2.14) and for CHD incidenc e was 1.52 (1.08-2.15). Subjects in the upper quartiles of fasting plasma g lucose showed a clustering of overweight, hypertension, elevated serum trig lycerides, reduced high density lipoprotein cholesterol and excess of small dense low density lipoprotein, suggestive of the Insulin Resistance Syndro me. Conclusion: Fasting plasma glucose levels in the upper normal range in non- diabetic elderly subjects appear to be associated with increased all-causes mortality and CHD, especially in women.