In 9 of the 14 national samples of diabetic patients assembled for the WHO Multinational Study of Vascular Disease in Diabetes additional laboratory data made it possible to relate manifestations of macrovascular disease to blood glucose concentrations as well as to diabetes duration and to other potential determinants. In five of the samples, serum triglyceride concentrations were also measured and were included in simple and multivariate analyses. Ischemic heart disease defined from Minnesota-coded EKGs and standardized WHO questionnaires was more strongly associated with serum triglyceride concentrations than with serum cholesterol concentrations, an association less notable in non-insulin-dependent diabetic patients. Ischemic heart disease was not related to the single fasting plasma glucose estimated for this study. Stroke and amputation were much more strongly related to the known duration of diabetes than was ischemic heart disease, and they were both related to blood glucose concentration measured at the time of study. Despite major variation in arterial disease prevalence rates between collaborating centers, risk for diabetic women appeared to equal that for diabetic men. The major variation in arterial disease prevalence between national groups could be accounted for only in part by the risk factors studied. Other factors, genetic or more likely environmental, are likely to contribute to the variation in arterial disease susceptibility and, if definable, may be potentially preventable.

To study the effects of improved control of blood glucose on markers of renal glomerular and tubular function, we initially determined, by radioimmunoassay technics, urinary excretion rates of albumin and beta2 microglobulin in 17 nondiabetic subjects and in 43 insulin-dependent, clinically nonproteinuric diabetic patients. Duration of diabetes ranged from six months to 39 years, and the patients were studied while receiving conventional therapy. Mean urinary albumin excretion was significantly elevated in the diabetics, but beta2-microglobulin excretion rates were not different from those of the controls, suggesting that the increased albumin excretion was due to increased transglomerular loss of albumin. Seven patients with long-term diabetes (duration of six to 33 years), selected because of elevated albumin excretion, were studied before and during a continuous, subcutaneous insulin infusion for a period of one to three days. Urinary albumin excretion was significantly reduced during the insulin infusion, but mean beta2-microglobulin excretion did not change. Strict control of blood glucose, even in the short term, may reverse a functional renal abnormality in long-duration, insulin-dependent diabetes.

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Letters to the Editor Is Diabetes Responsible for an Increase of the Mean Red Cell Volume? Dear Sir, The Short Communication of Davidson et al. [1] deserves some comment: The authors, who reported a higher mean red cell volume (MCV) in a group of 100 diabetic patients compared with a control group, were asking other investigators to contribute to the understanding of this result. We would like to make the following suggestions based on studies that we have carried out. We studied the MCV values in two populations of normal subjects (485 men in the first study [2], 995 men and women in the second one [3]), and we found in both cases a significant increase of MCV related to alcohol and tobacco consumption. The regression equations drawn from the second study showed that a difference of MCVvalue under 2 cu ~m, as observed by Davidson et al. in Aberdeen, might be due to relatively small differences in alcohol intake and/or smoking habits between the two groups. Thus, the small differences reported by Davidson et al. in the group of women are consistent with our findings. Unfortunately no data were given on alcohol and smoking habits. In addition, we were somewhat puzzled by the total absence of information regarding the control group. Hence, it was probably insufficient simply to exclude those subjects known to have an excessive alcohol intake. It would be necessary to perform further studies in order to assess precisely the possible effects of alcohol and smoking habits on MCV values. We are attempting to do this in our studies on diabetic subjects in order to throw further light on this interesting observation.

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