We cross-sectionally measured plasminogen activator inhibitor-1 (PAI-1) activity, fibrinogen, factor VII (FVII:C) and VIII (FVIII:C) coagulant activity, and von Willebrand factor antigen (VWF:Ag) in 162 traditional horticulturalists older than 40 years from the tropical island of Kitava, Papua New Guinea, where the intake of western food is negligible and where stroke and ischaemic heart disease appear to be absent. Identical analyses were made in Swedish subjects of comparable ages. Kitavams had markedly lower PAI-1 activity, with 85% of males and 100% of females having PAI-1 activity < or = 5 U/ml, as compared with 22 and 14% in Swedish males and females (p < 0.0001). Surprisingly, Kitavans also had higher FVII:C. FVIII:C and VWF:Ag. Fibrinogen was 10% lower in Kitavan males while 25% higher in Kitavan females. The very low PAI-1 activity in Kitavans may explain some of their apparent freedom from cardiovascular disease and probably relates to their extreme leanness.