Motivation: Recently, with urbanisation becoming an increasing trend, the African
population have been introduced to the westernised lifestyle. This contributed to severe
health implications and a rapid increase in cardiovascular morbidity and mortality in the
African population. In South Africa and other sub–Saharan African countries, the prevalence
of cardiovascular disease is increasing rapidly. The African population is thus regarded as a
high risk group, and we deem it necessary and important to investigate additional possible
cardiovascular risk markers in the attempt to improve the diagnosis of cardiovascular
diseases and the treatment thereof. We investigate double product as a possible
cardiovascular risk marker in African and Caucasian men from South Africa. Recent studies
have suggested that increased double product values might be an independent predictor of
cardiovascular morbidity and mortality. However, investigations on double product and endorgan
damage are limited in this population group. The strength of associations between
double product and various measurements of end–organ damage, including intima–media
thickness, left ventricular hypertrophy and albumin–to–creatinine ratio, are compared with the
associations between the more traditional risk factor, systolic blood pressure, and the
measurements of end–organ damage.
Aim: The aim of this study is to investigate the usability of double product as a possible
cardiovascular risk marker in African and Caucasian men from South Africa.
Methodology: The manuscript presented in Chapter 3 made use of the cross–sectional
SABPA (Sympathetic Activity and Ambulatory Blood Pressure in Africans) study, where 101
urbanised African and 101 Caucasian male school teachers from the North West Province of
South Africa were recruited. Anthropometric measurements were taken in triplicate using
standard methods. The cardiovascular measurements included 24–hour ambulatory blood
pressure and electrocardiogram measurements. Double products were calculated as the
product of 24–hour, daytime and night–time mean systolic blood pressure and mean heart
rate values. The carotid intima–media thickness was also obtained following the prescribed
protocols. A registered nurse collected blood samples and the biochemical measurements
were performed by independent laboratories, blinded to the subject’s cardiovascular profile.
Means and proportions were compared by standard t–tests and the x2 –tests, respectively.
The association between markers of end–organ damage and double product were investigated using single, partial and multiple regression analyses. All p–values <= 0.05 were
deemed significant.
Results and conclusions: Results from this study showed that Africans displayed
significantly higher systolic blood pressure values, heart rate values and subsequent double
product values compared to the Caucasians. Despite these significant differences, double
product only showed borderline significant correlations with the markers of end–organ
damage in African men, while no correlations were evident in Caucasian men. In African
men, systolic blood pressure displayed stronger and significant correlations with intimamedia
thickness, left ventricular hypertrophy, and albumin–to–creatinine ratio than double
product. These findings suggest that double product may not be a good marker of increased
risk for end–organ damage and subsequent cardiovascular–related mortality. / Thesis (M.Sc. (Physiology))--North-West University, Potchefstroom Campus, 2011.
| Identifer | oai:union.ndltd.org:NWUBOLOKA1/oai:dspace.nwu.ac.za:10394/4889 |
| Date | January 2010 |
| Creators | Schultz, Andreas Josias |
| Publisher | North-West University |
| Source Sets | North-West University |
| Detected Language | English |
| Type | Thesis |
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