The association between levels of socio-economic status and fibrin network architecture in women aged between 35 and 44 years

Abstract

Prospective epidemiological studies from 1980 to 1989 accumulated evidence of a possible relationship between cardiovascular disease and plasma fibrinogen concentration. It was soon evident that raised fibrinogen levels, causing hypercoagulable states, involve complex and multifactorial processes·. Consequently it is important to realise that hypercoagulability is associated with other risk factors of cardiovascular disease. This elevates the increasing importance of studying the haemostatic variables together with these risk factors. It is suspected however, that not only fibrinogen concentration, but also the quality of fibrin networks may contribute to coronary heart disease risk. It is known that other modulating factors in blood also affect the network structures as they are formed with otherwise constant fibrinogen and thrombin concentrations. Previous research extensively studied modulating factors such as albumin, glucose, smoking and diabetes. Socially patterned accumulation of health capital and cardiovascular risk begins in childhood. In the Whitehall II longitudinal study conducted by Brunner, adult occupational position was inversely associated with fibrinogen, other metabolic risk factors and risk factors like leisure time physical inactivity. Childhood, social position was associated with adult fibrinogen levels. The objective of this study was to determine the association between fibrin network architecture and socio-economic status in adult women. Three groups of adult women representing different socio-economic backgrounds were chosen randomly to voluntarily participate in the study. The study groups consisted of 27 white women (employees of the TFS), 30 "urbanized" black women (women living in an urbanized area for more than thirty years), and 30 "less urbanized" black women (women living in an urbanized area for less than thirty years). Fasting blood samples were taken on the premises of the Technikon Free State by a registered nurse and volunteers had medical examinations by a registered general practitioner. Fibrin network architecture variables and plasma fibrinogen were determined on fresh essentially platelet free plasma by standardised laboratory techniques. Other metabolic variables were performed on serum and full blood counts were performed on EDT A whole blood using standardised laboratory techniques. Results indicated that a association between socio-economic status and haemostatic profiles do exist. Many of the differences in analytical variables however, were expected and due to other relating factors such as ethnicity. The mean fibrinogen level of the white group of women was 3.S4±0.24 gIL. The group of black women defined as "less urbanized" displayed lower mean fibrinogen levels (3.16±.0.19 gIL). In contrast, the levels of the "urbanized" black women were much higher (4.04±0.22 gIL). However, these differences were not significant. This confirms the effect of urbanization and thus socio-economic status on plasma fibrinogen levels. Small differences were observed between network fibrin content and fibrinogen levels, and between mass length ratio and fibrinogen levels in all three the groups. It was unknown if these differences were static or in the process of development and an indication of future tendencies. Except for total protein values no significant differences were found between metabolic variables. This was expected as very strict inclusion/exclusion criteria were used to ensure that all volunteers were "apparently" healthy. This study in a way contradicts the hypothesis that socio-economic class itself may be the main cause of differences in some metabolic parameters from individuals within different levels of socio-economic backgrounds seeing as such strict exclusion criteria were used. It is believed that the factors related to the different levels of socio-economic status, such as the prevalence of tuberculosis, HIV, diabetes mellitus, hypercholesterolaemia, may play an important role in the outcome of the health status of the individuals within different levels of society. This study implies that the metabolic variables associated with different levels of socio-economic status are not necessarily associated with socio-economic class itself, but rather with the associated factors related to the different levels of socio-economic status. The study group was also very small which might have contributed to the lack of significance between groups. This study emphasises the need for prospective epidemiological trails to evaluate the true effect of socioeconomic variables and associated conditions on metabolic risk factors.