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.