SEX AND PARENTAL HYPERTENSION AS PREDICTORS OF WORSENED RED-BLOOD-CELL MEMBRANE ENZYME-ACTIVITIES IN TYPE-1 INSULIN-DEPENDENT DIABETIC SUBJECTS

The possibility that distinct genetic factors may concur, in associati on with diabetes, to increase susceptibility to vascular morbidity, in cluding hypertension, has been evaluated in ninety-four normotensive i nsulin-dependent diabetic patients by testing both the frequency and p revalence of hypertension in parents and by measuring membrane red blo od cell enzyme activities. Parental hypertension was present in a sign ificantly higher proportion of diabetic compared to control subjects. A significant decrease in basal membrane red blood cell (Na+-K+), (Mg2 +) and (Ca2+) ATPase activities was also related to the disease and wa s apparently uninfluenced by short - or long term metabolic control. I n contrast with what was observed in the control group, sex caused in diabetic subjects significant variations in red blood cell enzyme acti vities, with women showing the lowest mean basal values of all enzyme activities. Parental hypertension turned out to be an independent risk factor in significantly reducing red blood cell enzyme activities bot h in diabetic and control subjects. However, whereas in diabetic subje cts sex interacted strongly with parental hypertension in causing redu ction of enzyme activities, in controls the effect of parental hypeten sion was sex-independent and significantly reduced basal enzyme activi ties, thus rendering subjects similar to diabetics. It is concluded th at both sex and parental hypertension in association with diabetes, ar e predictors of further damage to red blood cell enzyme activities, wh ich may thus be linked to increased risk of susceptibility towards vas cular complications.