With recent advances in diabetes treatment, especially the evidence that tight control of glycemia, diminishes glycemia related complications it is becoming apparent that the main barriers to further increases in the longevity of patients with insulin-dependent (type 1) diabetes mellitus are the long-term cardiovascular complications of this condition. However, development of effective strategies to prevent cardiovascular complications of diabetes have been impeded by uncertainty as to the relative importance in their pathogenesis of hyperglycemia, early renal dysfunction or excess levels of conventional risk factors. In this context, research to elucidate the predictors of cardiovascular complications of diabetes in well-characterized populations followed long term has the potential to be of considerable clinical and public health importance.