Risk of Cardiovascular Disease in a Traditional African Population with a High Infectious Load: A Population-Based Study

Westendorp RGJ (2012) Risk of Cardiovascular Disease in a Traditional African Population with a High Infectious Load: A Population-Based Study. PLoS ONE 7(10): e46855. doi:10.1371/journal.pone.0046855 Risk of Cardiovascular Disease in a Traditional African Population with a High Infectious Load: A Population- Based Study Jacob J. E. Koopman 0 David van Bodegom 0 J. Wouter Jukem 0 a 0 Rudi G. J. Westendor 0 p 0 Stefan Kiechl, Innsbruck Medical University, Austria 0 1 Department of Gerontology and Geriatrics, Leiden University Medical Center , Leiden , The Netherlands , 2 Department of Gerontology and Geriatrics, Leiden University Medical Center , Leiden , The Netherlands , 3 Department of Cardiology, Leiden University Medical ZCenter , Leiden, 4TDheepartmenNteothfeGrelaronndtso,logy and Geriatrics , Leiden University Medical Center , Leiden , The Netherlands , 5 Leyden Academy on Vitality and Ageing , Leiden , The Netherlands Background: To test the inflammatory origin of cardiovascular disease, as opposed to its origin in western lifestyle. Population-based assessment of the prevalences of cardiovascular risk factors and cardiovascular disease in an inflammation-prone African population, including electrocardiography and ankle-arm index measurement. Comparison with known prevalences in American and European societies. Methodology/Principal Findings: Traditional population in rural Ghana, characterised by adverse environmental conditions and a high infectious load. Population-based sample of 924 individuals aged 50 years and older. Median values for cardiovascular risk factors, including waist circumference, BMI, blood pressure, and markers of glucose and lipid metabolism and inflammation. Prevalence of myocardial infarction detected by electrocardiography and prevalence of peripheral arterial disease detected by ankle-arm index. When compared to western societies, we found the Ghanaians to have more proinflammatory profiles and less cardiovascular risk factors, including obesity, dysglycaemia, dyslipidaemia, and hypertension. Prevalences of cardiovascular disease were also lower. Definite myocardial infarction was present in 1.2% (95%CI: 0.6 to 2.4%). Peripheral arterial disease was present in 2.8% (95%CI: 1.9 to 4.1%). Conclusions/Significance: Taken together, our data indicate that for the pathogenesis of cardiovascular disease inflammatory processes alone do not suffice and additional factors, probably lifestyle-related, are mandatory. - Funding: This research has been supported by the Netherlands Foundation for the Advancements of Tropical Research (WOTRO 93467), the Netherlands Organization for Scientific Research (NOW 051-14-050), the European Union funded Network of Excellence LifeSpan (FP6 036894), a grant of the Board of Leiden University Medical Center, and Stichting Dioraphte. The funders have had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. The pathogenesis of cardiovascular disease has long been described as an accumulation of lipids in a dysfunctional endothelial wall, driven by lifestyle-related factors such as smoking, dyslipidaemia, dysglycaemia, obesity, and hypertension. Since the end of the millennium, it has been commonly accepted that inflammatory processes play a prominent role in atherosclerosis, reclassifying cardiovascular disease as a chronic inflammatory disorder [13]. Still, the exact balance between lifestyle and inflammation in its causality has remained unclear. There are both indications of subendothelial lipid retention [4] and inflammation [1] as being the primary causative factor. The lifestyle-related risk factors are mainly present in western societies, which have experienced an epidemiologic and demographic transition. In these countries, cardiovascular disease is one of the major causes of morbidity and the most common cause of mortality. In developing countries, where these risk factors are absent, infectious diseases prevail [5]. Without the public health care of western societies, infectious diseases are highly lethal. Selectively those individuals that resist the high infectious pressure by a strong inflammatory response will survive, resulting in a population expressing a selectively proinflammatory immune system [610]. If cardiovascular disease is an inflammatory disease, it can be expected to be provoked by such a proinflammatory status. Indeed, with the progressing control of lethal infectious diseases, cardiovascular pathology is becoming more frequent in developing countries, especially in semideveloped environments where a western lifestyle concurs with a high infectious load [5,11,12]. Within western countries, the cardiovascular risk of migrants from developing countries remains elevated [1214]. Inflammatory markers are used to predict cardiovascular risk [2,3]. These figures reinforce the dominant role of inflammation in cardiovascular pathogenesis. However, the occurrence of cardiovascular disease in the remote and rural regions of developing countries, where a high infectious load induces proinflammatory phenotypes but a western lifestyle is absent, has infrequently been studied [1517]. Knowledge on these data could further unravel the roles of lifestyle and inflammation as the origins of cardiovascular disease. We have conducted a large population study in rural Ghana in West Africa. This study population has only recently started to experience an epidemiologic transition; the elderly are therefore not only a subgroup that has survived the pretransitional past, but have also been exposed to a pretransitional environment during the largest part of their lives [18]. Previous immunologic and genetic studies have shown this population to exhibit a proinflammatory immune status [810]. A previous study in a comparable population of forager-horticulturalists in Bolivia provided a first indication of a low prevalence of cardiovascular disease in populations where a western lifestyle is uncommon [7]. Our study population concerns a purely horticultural population where lifestyle-related risk factors are even more exceptional. This study firstly extends previous observations with a detailed assessment of cardiovascular health in a traditional African population, including electrocardiography and ultrasound measurement of ankle-arm indexes. Research area The Upper East Region in Ghana is remote, rural, and one of the least developed regions of the country. The vast majority of the inhabitants are involved in non-commercial agriculture performed by manual labor [19]. The yearly per capita income averages US$ 135 [20]; 88% of the households lives in poverty [21]. Infectious diseases are the main causes of death [22]. Since 2002, we have registered and followed a traditional horticultural population in the Garu-Tempane District in the Upper East Region occupying a res (...truncated)