MODERATE WEIGHT-REDUCTION IMPROVES RED-CELL AGGREGATION AND FACTOR-VII ACTIVITY IN OVERWEIGHT SUBJECTS

OBJECTIVE: To investigate the effect of a dietary intervention to redu ce body weight on red cell aggregation (RCA), factor VII activity, pla sminogen activator inhibitor (PAI) activity, tissue plasminogen activa tor (t-PA) antigen, fibrinogen, whole blood and plasma viscosity, haem atocrit and lipids. DESIGN: Open single stranded study of dietary inte rvention for weight loss in a volunteer sample. SUBJECTS: Forty-five s ubjects whose BMI exceeded 26 kg/m(2) were recruited and received diet etic advice designed to reduce body weight by 0.5 kg per week. MEASURE MENTS: Body weight and waist and hip circumferences, dietary intake by seven day weighed inventory, RCA, factor VII activity, PAI activity, t-PA antigen, fibrinogen, whole blood and plasma viscosity, haematocri t and lipids. RESULTS: After 12 weeks of dietary intervention there we re reductions in body weight and BMI by 5.9 (s.d. 3.3) kg and 1.9 (s.d . 1.0) kg/m(2) respectively in males, and 4.1 (s.d. 2.9) kg and 1.6 (s .d. 1.1)kg/m(2) in females (P < 0.0001). Factor VII activity (P=0.0043 ), RCA (P=0.01) and t-PA antigen (P=0.016) were reduced in females aft er weight reduction but no differences were found in PAI activity, who le blood, plasma viscosity or haematocrit. The changes in factor VII a ctivity and RCA were appropriate for the changes in BMI on the basis o f the relationships of the risk factors with BMI in a cross sectional survey of a representative Scottish population. Plasma total cholester ol was reduced (P=0.016) but HDL cholesterol and triglycerides remaine d unchanged. There were significant associations between the reduction s in factor VII activity and BMI (r=0.395, P=0.013) and between the re ductions in RCA and waist to hip ratio (r=0.350, P=0.04). No relations hip was seen between changes in serum cholesterol and changes in facto r VII activity or RCA. CONCLUSIONS: Modest weight loss, of 5% body wei ght, with conventional dietary intervention reduces two established ri sk factors for ischaemic heart disease (factor VII activity and RCA) w hich are generally elevated in those with increased body weight.