Extract:

Literature Review: Factors affecting cardiovascular health

Introduction

Blood pressure is considered to be a well-established measure of cardiovascular health (Kelley, Kelley & Tran, 2001) and is determined by both genetic and environmental factors (Turnpenny & Ellard 2005). Hypertension, or high blood pressure, is unique in that it can simultaneously be regarded as a cardiovascular disease in itself and a risk factor (Powers & Dodd 2003). Various studies have found positive associations between hypertension and risk of developing coronary heart disease (e.g. Wang et al. 2006). Identification of the genes involved in hypertension is an extremely well researched area. Recent research by Zhu et al (2005) has found evidence for loci of major importance in influencing hypertension on chromosomes 6q24 and 21q21.

Despite the identification of large numbers of genetic loci that are potentially involved in the determination of cardiovascular health and disease, the results are inconsistent. One of the main criticisms of genetic association studies is failure to replicate findings; Hirschorn et al. (2002, as cited in Sturm 2004) showed that only 3.6 % of associations between common gene variants and disease have been consistently replicated.

Evidence suggests that cardiovascular disease is a multifactorial disorder, i.e. cardiovascular health is determined by multiple genetic and environmental factors (Powers & Dodd 2003; Turnpenny & Ellard 2005). Although several susceptibility loci associated with cardiovascular disease and its risk factors have been found, we do not currently have a complete understanding of the complex genetics involved. However, Sturm (2004) argues that the primary goal of cardiovascular genetic research can now be achieved to reduce morbidity and mortality due to cardiovascular disease by identifying people who are most at risk through genetic counselling. As well as possible drug therapy, a key component of this counselling should be an individualised plan to include lifestyle changes to improve cardiovascular health and reduce the risk of disease. This review will now focus on the role of lifestyle factors in cardiovascular health and disease.

Physical Activity

Lack of physical activity has been recognised as a major risk factor for cardiovascular disease since 1992 (Powers & Dodd 2003). There is indisputable evidence to show that regular exercise is effective for improving cardiovascular health and reducing disease. This evidence comes from both laboratory studies of monkeys (e.g. Williams et al. 2003) and natural studies of both leisure and occupational activity in humans (e.g. Noda et al. 2005; Hu et al. 2005). In spite of this evidence, many people still do not engage in frequent physical activity. Relative to other risk factors for cardiovascular disease, a sedentary lifestyle is of high prevalence (as illustrated in Figure 2).