Nutritional status influences plasma fibrinogen concentration: evidence from the THUSA survey

Nutritional status and risk factors for chronic diseases, including plasma fibrinogen and its determinants, of Africans in the Northwest Province of South Africa, have been studied in a cross-sectional survey. A representative sample of 1854 "apparently healthy" African men and women volunteers aged 15 years and older was recruited from 37 randomly selected sites throughout the Province and stratified for level of urbanisation. Information was collected using validated and culture-sensitive questionnaires. Fasting blood samples were drawn, and all measurements were done with standardised methodology using appropriate equipment, procedures, and controls. Fibrinogen concentration was measured in citrated plasma with the method of Clauss, using the ACL200 automated system and the international fibrinogen standard. The results revealed a population with a high mean plasma fibrinogen (3.17+/-1.10 g/L for HIV-negative men and 3. 64+/-1.12 g/L for HIV-negative women). Factors known to influence plasma fibrinogen, such as age, gender, smoking habit, and physical activity, were also observed in this population. Young rural men and women had the lowest fibrinogen level. Nasal snuff taking and HIV infection did not influence fibrinogen concentration. Multivariate analyses revealed that lower plasma fibrinogen was associated with low to normal body mass index in women, and with dietary intakes compatible with prudent dietary guidelines in men and women (low intakes of animal protein; trans fatty acids and higher intakes of plant protein; dietary fibre, vitamin E, and iron, and a high dietary P/S ratio). Subjects in the higher quartiles of plasma fibrinogen had significantly lower iron, vitamin E, and vitamin B6 (women) status. Increases in fibrinogen were associated with significant increases in serum lipids. Both under- and overnutrition seem to be associated with high plasma fibrinogen. It is concluded that overall nutritional status, possibly in addition to specific nutrients (and foods), influences plasma fibrinogen.