Chronic Non-communicable Diseases in Low and Middle-income Countries

Ama de-Graft Aikins, Charles Agyemang, Ama de-Graft Aikins, Charles Agyemang

• Publisher: CAB International
• Year: 2015
• ISBN:
  9781789244922
• Topic: Medicine
• Subtopic: Public Health, Administration & Care

Low and middle income countries in Africa, Asia and Latin America bear a significant proportion of the global burden of chronic non-communicable diseases. This book synthesizes evidence across countries that share similar socio-economic, developmental and public health profiles, including rapid urbanization, globalization and poverty. Providing insights on successful and sustainable interventions and policies, it shows how to slow and reverse the rising burden of chronic diseases in resource-poor settings.

1 Cardiovascular Diseases and Established Risk Factors in Low- and Middle-income Countries

RAPHAEL BAFFOUR AWUAH¹, ERNEST AFRIFA-ANANE¹ AND CHARLES AGYEMANG^2*

¹Regional Institute for Population Studies, University of Ghana, Accra, Ghana; ²Department of Public Health, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands

1.1 Introduction

Cardiovascular diseases (CVDs) are the leading cause of mortality worldwide, with more deaths from CVDs than from any other cause annually [1]. In 2008, it was estimated that CVDs accounted for over 17 million deaths worldwide from a total of 57 million [1]. The CVD burden varies across different world regions. In high-income countries, CVD-related deaths have declined progressively since the mid-20th century because of successful preventive strategies and improved treatment for acute CVD events [2]. By contrast, in many low- and middle-income countries (LMICs), CVD rates are increasing rapidly, and CVD is already the leading cause of death in many countries [3]. It is estimated that over 80% of deaths attributable to CVDs occur in LMICs, with the occurrence being equally distributed among men and women [1]. Estimates show that LMICs experience 300–600 CVD deaths per 100,000 of the population, which is higher than in most high-income countries [1]. This is an unfortunate paradox because many years of progress in the fight against CVD in most high-income countries is being superseded by the rapidly increasing CVD burden in many LMICs [4].

The total number of CVD deaths (mainly stroke and coronary heart disease (CHD)) increased globally from 14.4 million in 1990 to 17.5 million in 2005. Of these deaths, 7.6 million were attributed to CHD and 5.7 million were attributed to stroke [5]. About 51% of deaths due to stroke and 45% of deaths due to CHD are also attributable to hypertension [6, 7].

The burden of CVD in LMICs is expected to increase further. It is estimated that over 23 million people will die from CVD by 2030 [1, 8] and it will remain the single leading cause of mortality and morbidity [8], more than infectious diseases (including human immunodeficiency virus/AIDS, tuberculosis and malaria), maternal and perinatal conditions, and nutritional disorders combined [9]. The largest increase in terms of percentage will occur in the Eastern Mediterranean region and the largest increase in number of deaths in the South-east Asia region.

The main drivers of the increasing burden of CVD in LMICs are the increasing trends in the prevalence of risk factors such as hypertension, obesity and diabetes. Time trend analyses, for example, indicate that the prevalence of obesity in urban West Africa has more than doubled over the last 15 years [10]. The most important behavioural risk factors of CVD are unhealthy diet, physical inactivity and tobacco use. The effects of unhealthy diet and physical inactivity may lead to hypertension, diabetes, dyslipidaemia, overweight and obesity, and subsequent CVDs. This clearly reflects the changing lifestyles in most LMICs, such as consumption of energy-dense foods and refined sugars complemented by less-energy-demanding jobs, particularly in the urban settings. The changing lifestyle is driven mainly by rapid economic growth coupled with the rapid pace of urbanization in LMICs. It has been suggested that it is the rapid development and resulting changes in the social fabric and physical environment that are accelerating the CVD and other chronic diseases epidemic in LMICs [4]. The potentially devastating effects of this trend are magnified by a detrimental economic impact on households and nations, where poverty can be both a contributing cause and a consequence of CVDs and other chronic diseases [2].

The increasing burden of CVD is occurring at a time when communicable diseases are still highly prevalent, particularly in Africa and South-east Asia, placing a great demand on the overburdened and impoverished healthcare systems in many of these countries.

Below we describe the current burden of the main CVDs (i.e. stroke and CHD) and their main risk factors (i.e. hypertension, diabetes, obesity, smoking, physical inactivity, excessive alcohol consumption) in the last 15 years using data from individual studies and systematic review articles known to the authors. Literature searches were performed using electronic databases (PubMed, PsycINFO and Google Scholar) that reported data on the epidemiology of stroke, CHD, hypertension and diabetes, overweight and obesity, smoking, physical inactivity and alcohol consumption in Africa, Asia, the Middle East, Latin America and the Caribbean. The articles used in this review consist of scholarly papers published between 2000 and 2014.

1.2 The Burden of CVD

Stroke

The prevalence of stroke in LMICs in the period between 2000 and 2014 ranged from 114 per 100,000 people in an urban community in Nigeria [11] to 9300 per 100,000 people in an urban area in China [12]. In rural areas of LMICs, the prevalence of stroke ranged from 243 per 100,000 in South Africa [13] to 6500 per 100,000 in Mexico [12]. The prevalence of stroke varied between different studies for some countries. For example, in Egypt, the prevalence of stroke ranged from 508 per 100,000 [14] to 963 per 100,000 [15]. The incidence of stroke ranged from 25 per 100,000 in Nigeria [16] to 250 per 100,000 in Egypt [17]. The prevalence and incidence of stroke was higher in men than in women.

The estimates indicated that stroke prevalence and mortality rates were 25% greater in LMICs relative to high-income countries [18]. Furthermore, a study of 56 population-based registries worldwide showed that there was a 42% decrease in stroke incidence in high-income countries, whereas LMICs experienced a 100% increase in stroke incidence from 1970 to 2008 [19]. In the absence of any meaningful clinical or public health interventions, it is expected that the incidence of stroke will increase further in LMICs.

Coronary heart disease

CHD, the principal component of CVD, is the leading cause of death in all World Health Organization (WHO) regions of the world except for the African region [20]. CHD is not only a disease of the elderly in high-income countries but also has a major global impact on the economically active population, and is a growing concern for LMICs [21]. Even in sub-Saharan Africa, where CHD was not considered as a major public health concern, it now ranks eighth among the leading causes of death in men and women in the region [22]. More importantly, among people aged >60 years, CHD is already the leading cause of death in men and the second leading cause of death in women in the African region. Mensah’s study showed the age-adjusted mortality rate for CHD ranged from 111 per 100,000 in Algeria to 277 per 100,000 in Mauritius in men, and 49 per 100,000 in the Seychelles to 161 per 100,000 in Mauritius among women [22]. Additionally, in China, the age-adjusted death rate from CHD in the period under review was 80–128 per 100,000 for men and 57–98 per 100,000 for women [23]. Furthermore, among men aged 35–64, CHD mortality rates were 64–106 per 100,000 in China [24]. High mortality levels have also been reported in many LMICs. Age-standardized mortality due to CHD was 110 per 100,000 in the Federated States of Micronesia, 125 per 100,000 in Samoa and 181 per 100,000 in Nauru [7]. In Mexico, the age-adjusted mortality due to CHD in the year 2000 was 82 per 100,000 in men and 53 per 100,000 in women [25]. In India, it was estimated that 31.8 million people were living with CHD in 2001 [26].

The age-adjusted prevalence of CHD in Iran was 12.7% [27], 5.5% in Saudi Arabia [28] and 5.9% in Jordan [29]. The rising prevalence of risk factors such as hypertension and diabetes, as well as the weak and overstretched health systems in most LMICs, will most likely exacerbate the burden of CHD in these regions.

1.3 Risk Factors of CVD

1.3.1 Metabolic risk factors

Hypertension

We considered articles that defined hypertension as a measured blood pressure of >140 mmHg systolic and/or >90 mmHg diastolic or as those receiving anti-hypertensive therapy. The prevalence of hypertension ranged from 6.8% in a rural community in Mexico [30] to 69.9% in an urban study among individuals aged 70 and above in Tanzania [31]. The prevalence in rural areas ranged between 6.8% in Mexico [30] and 42.9% in Brazil [32]. The prevalence of hypertension in urban areas, on the other hand, ranged from 12.3% in Kenya [33] to 69.9% in Tanzania [31]. There was a higher hypertension prevalence among males than among females. There were considerable differences in the prevalence of hypertension in studies conducted in the same country. For example, the prevalence of hypertension ranged from 21.9% [34] to 42.1% [35] in China, from 9.3% [36] to 30.3% [37] in Ethiopia and from 15% [38] to 30.3% [39] in India. The evidence from the studies included in this review suggests that the prevalence of hypertension is comparable to that found in high-income countries. The African region has the highest prevalence rate, 46% of adults aged 25 and above, whereas the Americas have the lowest prevalence, at 35%.

Despite the increasing burden of hypertension in LMICs, a large number of people with hypertension are undiagnosed, untreated and uncontrolled [40]. As of 2008, almost 1 billion people had uncontrolled hypertension worldwide [41]. This means that a large number of people in LMICs will be affected by hypertension-related complications unless major efforts are made to halt or reduce the current rising prevalence of hypertension and its poor control.

Diabetes

With regard to diabetes (type 2), articles were included if they reported the prevalence of the condition, impaired fasting glucose and/or impaired glucose tolerance. The prevalence of diabetes in LMICs was as low as 0.4% in a rural community in Uganda [42] and as high as 26.3% in a study conducted in an urban community in South Africa [43]. Most of the studies reported a higher diabetes prevalence among men compared with women. The prevalence in rural settings ranged between 0.4% in Uganda [42] and 17.5% in Sri Lanka [44]. In the studies that focused on urban communities, the prevalence was from 4.4% in Peru [45] to 26.3% in South Africa [43]. The prevalence of impaired glucose tolerance was from 2.2% in an urban community in Nigeria [46] to 21.6% in Ethiopia [47], while the prevalence of impaired fasting glucose ranged from 1.2% in an urban town in South Africa [48] to 12.1% in a study conducted in a rural community in Angola [49]. Studies conducted in the same country showed some variation in the prevalence of diabetes. For example, the prevalence of diabetes ranged from 4.3% in rural India [50] to 24.6% in urban India [51].

The review of studies on diabetes in LMICs indicated that the rates are as high as rates observed in high-income countries [52]. The number of individuals with diabetes in LMICs is likely to be even higher than current estimates because of a substantial proportion of people living with diabetes who are undetected [53]. This leads to an increase in diabetes complications (principally nephropathy, retinopathy, neuropathy and small-vessel vasculopathy causing lower extremity amputation). These complications account for much of the social and financial burden of diabetes in LMICs [52]. According to the latest estimates from the International Diabetes Federation, the African region has the highest proportion of undiagnosed type 2 diabetes (63%), and over half a million people in the region died from diabetes-related causes in 2013 [53]. This represents 8.6% of deaths from all causes in adults in the region. Moreover, despite the predominantly urban impact of the epidemic, diabetes is fast becoming a major health problem in rural communities in LMICs [54].

The rising prevalence of diabetes in LMICs is, to a large extent, attributed to rapid globalization and urbanization, with subsequent changes in diet, a reduction in physical activity levels and the adoption of sedentary lifestyles. The diabetes epidemic has increased in line with the worldwide rise in overweight and obesity.

Obesity

The prevalence of overweight and obesity is increasing at an alarming rate in both high-income countries and LMICs throughout the globe. WHO estimates indicate that the undernourished population in the world has declined, whereas the overnourished population has increased significantly [55]. Data from WHO show that, globally, there are more than 1 billion adults who are overweight and 300 million obese people. LMICs have been particularly affected, with obesity rates having increased more than threefold since 1980 in the Pacific Islands, Australasia and China [55]. Overweight and obesity are important risk factors for diabetes, CVD, cancer and premature death. In a review of CHD among LMICs, Gaziano et al. found a high population attribution factor of 10 and 5%, respectively, for Eastern Asia and Pacific and South Asia and 8% for sub-Saharan Africa [25]. In addition, Kelly et al. reported an average prevalence of overweight of 20.4% among women and 16.8% among men for Asian countries compared with those of sub-Saharan Africa, which were 17.5 and 12.1% for women and men, respectively [56]. Although explanations for the high prevalence are complex, it can be attributed to factors such as changes in dietary patterns, low physical activity levels and sedentary behaviours due to increased used of motorized vehicles as urbanization increases [57]. The gender-based prevalence from the studies indicates that women have been more affected by overweight and obesity than men. In India, 30% of females aged 25 and above were considered to be obese compared with 18% of their male counterparts [58]. Urban residents have also been more affected by overweight and obesity compared with rural residents. For example, in Cameroon, 17.1% versus 5.4% of urban women and men and 3% versus 0.5% of rural women and men, respectively, were found to be obese [59].

As the overweight and obesity epidemic positively correlates with the rising burden of CVD in LMICs, their reduction will have a major impact in reducing the current CVD burden worldwide.

Dyslipidaemia

High cholesterol levels increase the risks of heart disease and stroke [60]. About one-third of CHD is attributable to high cholesterol globally. High cholesterol...

Table of contents

• Cover Page
• Title Page
• Copyright Page
• Contents
• Contributors
• Abbreviations
• Introduction: Addressing the Chronic Non-communicable Disease Burden in Low- and Middle-income Countries
• Part I
• Part II
• Part III
• Index
• Footnotes