Food intake, fibrinolysis and risk factors for cardiovascular disease : studies with special focus on plasminogen activator inhibitor type 1 (PAI-1)

Sammanfattning: Elevated plasminogen activator inhibitor (PAI-1) activity levels, hyperlipemia, hypertension, impaired glucose tolerance and obesity, in particular central obesity, are all related to increased risk for the development of cardiovascular disease.Some risk factors are known to be and shown to be influenced by dietary habits. One aim of this study was to determine the distribution of PAI-1 activity and its linkage to serum lipids, body build, glucose and insulin (including glucose tolerance) among healthy men and women. Another aim was to elucidate the effects of different diet programes on the relationship between PAI-1 activity, serum lipid, glucose and insulin levels.Two cross-sectional studies, involving 260 individuals, the Norsjö study 1986, the mean PAI-1 activity among 30-60 year-old men was7.9 U/mL and among women 7.8 U/mL. Both men and women with a body mass index over 27 kg/m2 had higher PAI-1 activity, tPA antigen, fasting insulin and insulin responses following an oral glucose tolerance test than persons with body mass index <27. They also had lower HDL-cholesterol. Women with a high waist/hip circumference ratio had a higher mean PAI-1 activity, tPA antigen, triglyceride, blood pressure and insulin response to an oral glucose tolerance test than women with low or normal waist/hip ratio. Men with high waist/hip ratio had higher tPA antigen, glucose and insulin responses to an oral glucose tolerance test than men with low or normal waist/hip ratio.In two dietary studies different low-energy diets (a juice fast or a weight reduction program) were followed. PAI-1 activity was decreased in both cases. In a third dietary study, transition from a high-fat/low-carbohydrate diet to a low-fat/high-carbohydrate diet decreased PAI-1 activity provided that it did not also cause a substantial increase in triglycerides or glucose. In a fourth dietary study the regular diet was supplemented with oat-husk. PAI-1 activity was reduced; a small increase in glucose but not in triglyceride levels was observed.On the basis of these results it is concluded that PAI-1 activity levels are associated with constitutional factors such as body mass index and waist/hip ratio. PAI-1 is elevated in obesity. Nutritional factors are also of importance for the PAI-1 activity levels. PAI-1 activity levels can be reduced by dietary regiments such as low-energy diets or high-fiber diets.