Population causes and consequences of leading chronic diseases: a comparative analysis of prevailing explanations

CONTEXT: The mortality numbers and rates of chronic disease are rising faster in developing than in developed countries. This article compares prevailing explanations of population chronic disease trends with theoretical and empirical models of population chronic disease epidemiology and assesses some economic consequences of the growth of chronic diseases in developing countries based on the experiences of developed countries. METHODS: Four decades of male mortality rates of cardiovascular and chronic noncommunicable diseases were regressed on changes in and levels of country income per capita, market integration, foreign direct investment, urbanization rates, and population aging in fifty-six countries for which comparative data were available. Neoclassical economic growth models were used to estimate the effect of the mortality rates of chronic noncommunicable diseases on economic growth in high-income OECD countries. FINDINGS: Processes of economic growth, market integration, foreign direct investment, and urbanization were significant determinants of long-term changes in mortality rates of heart disease and chronic noncommunicable disease, and the observed relationships with these social and economic factors were roughly three times stronger than the relationships with the population's aging. In low-income countries, higher levels of country income per capita, population urbanization, foreign direct investment, and market integration were associated with greater mortality rates of heart disease and chronic noncommunicable disease, less increased or sometimes reduced rates in middle-income countries, and decreased rates in high-income countries. Each 10 percent increase in the working-age mortality rates of chronic noncommunicable disease decreased economic growth rates by close to a half percent. CONCLUSIONS: Macrosocial and macroeconomic forces are major determinants of population rises in chronic disease mortality, and some prevailing demographic explanations, such as population aging, are incomplete on methodological, empirical, and policy grounds. Rising chronic disease mortality rates will significantly reduce economic growth in developing countries and further widen the health and economic gap between the developed and developing world.     

The global impact of noncommunicable diseases: estimates and projections

With the aging of populations in developing countries there is both a demographic and an epidemiological transition which affects the impact of chronic degenerative diseases on the health status of the populations. Demographic transition takes place in countries where there are effective programmes of disease control which allow for survival during the early years of childhood and adolescence. This results in an increase in life expectancy which places larger proportions of the population in the age range (60 years and older) in which chronic degenerative diseases become the major determinants of health status. Epidemiological transition in diseases may also be brought about by shifts in social and economic patterns which favour detrimental changes in risk factors for the chronic degenerative diseases. Such changes may include health-related behaviour which augments dietary consumption of fats and alcohol, increases obesity, increases smoking and decreases physical activity. Such changes in risk-factor levels increase the prevalence of chronic degenerative diseases which manifest themselves at later ages, and for which early preventive actions could be cost-effective. In order to illustrate the impact of both demographic and risk-factor effects, analyses are made of the impact of increases in life expectancy on cause-specific mortality in both developing and developed countries. It is shown that there is great similarity in the effect of major noncommunicable diseases on the life expectancy of adults in both developed and developing countries. The major differences are seen to be in the proportions of deaths expected from such diseases as cancer, diabetes, heart disease, stroke and cirrhosis; but not in the distribution of age at death which is the better measure of disease impact. Demographic analyses, computing indirect estimates of mortality, also demonstrate that there are currently more chronic disease deaths in developing than developed countries and that as expectation of life increases in developing countries the global chronic disease burden will be greatly concentrated in the developing countries. Analyses of risk-factor reduction by feasible intervention strategies, e.g. smoking cessation campaigns, treatment of high blood pressure, using relationships between risk factors and diseases established in longitudinal studies carried out in developed countries, point out that the effect of risk-factor control in long-living populations can be hidden by the dependency of risk factors and various related causes of death, e.g. smoking has an impact on lung cancer, ischaemic heart disease and emphysema, but at different ages.(ABSTRACT TRUNCATED AT 400 WORDS)     

What can public health nutritionists do to curb the epidemic of nutrition-related noncommunicable disease?

As a result of the rapid shift in dietary and activity patterns, the world is facing a pandemic of obesity. This new global pandemic is rapidly becoming a problem of the poor. Extensive work has been undertaken to document the changes in weight and, to a much lesser extent, in diet, energy expenditures, and activity patterns. Broad-based creative public health actions are needed to offset these larger forces that promote energy imbalance, poor diets, and reduced physical activity. Inaction will result in an acceleration of morbidity, disability, and deaths from major nutrition-related noncommunicable diseases – primarily in developing countries.     

Inequalities in Noncommunicable Disease Mortality in the Ten Largest Japanese Cities

The burden of noncommunicable diseases and social inequalities in health among urban populations is becoming a common problem around the world. This phenomenon is further compounded by population aging. Japan faces the task of maintaining its high level of population health while dealing with these challenges. This study focused on the ten largest cities in Japan and, using publicly available administrative data, analyzed standardized mortality ratios to examine inequalities in relative mortality levels due to major noncommunicable disease at both city and subcity levels. On average, the ten major cities had excess mortality due to cancer and lower mortality due to heart disease and cerebrovascular disease compared to the country as a whole. Substantial inequalities in relative mortality were observed both between and within cities, especially for heart disease and cerebrovascular disease among men. Inequalities in relative mortality levels within cities appear to be increasing over time even while relative mortality levels are decreasing overall. The widely observed health inequalities signal the need for actions to ensure health equity while addressing the burden of noncommunicable diseases. Increasingly, more countries will have to deal with these challenges of inequity, urbanization, aging, and noncommunicable diseases. Local health governance informed by locally specific data on health determinants and outcomes is essential for developing contextualized interventions to improve health and health equity in major urban areas.     

Epidemiological and nutrition transition in developing countries: impact on human health and development

Whereas common infectious and parasitic diseases such as malaria and the HIV/AIDS pandemic remain major unresolved health problems in many developing countries, emerging non-communicable diseases relating to diet and lifestyle have been increasing over the last two decades, thus creating a double burden of disease and impacting negatively on already over-stretched health services in these countries. Prevalence rates for type 2 diabetes mellitus and CVD in sub-Saharan Africa have seen a 10-fold increase in the last 20 years. In the Arab Gulf current prevalence rates are between 25 and 35% for the adult population, whilst evidence of the metabolic syndrome is emerging in children and adolescents. The present review focuses on the concept of the epidemiological and nutritional transition. It looks at historical trends in socio-economic status and lifestyle and trends in nutrition-related non-communicable diseases over the last two decades, particularly in developing countries with rising income levels, as well as the other extreme of poverty, chronic hunger and coping strategies and metabolic adaptations in fetal life that predispose to non-communicable disease risk in later life. The role of preventable environmental risk factors for obesity and the metabolic syndrome in developing countries is emphasized and also these challenges are related to meeting the millennium development goals. The possible implications of these changing trends for human and economic development in poorly-resourced healthcare settings and the implications for nutrition training are also discussed.     

Health transition in Africa: practical policy proposals for primary care

Sub-Saharan Africa is undergoing health transition as increased globalization and accompanying urbanization are causing a double burden of communicable and noncommunicable diseases. Rates of communicable diseases such as HIV/AIDS, tuberculosis and malaria in Africa are the highest in the world. The impact of noncommunicable diseases is also increasing. For example, age-standardized mortality from cardiovascular disease may be up to three times higher in some African than in some European countries. As the entry point into the health service for most people, primary care plays a key role in delivering communicable disease prevention and care interventions. This role could be extended to focus on noncommunicable diseases as well, within the context of efforts to strengthen health systems by improving primary-care delivery. We put forward practical policy proposals to improve the primary-care response to the problems posed by health transition: (i) improving data on communicable and noncommunicable diseases; (ii) implementing a structured approach to the improved delivery of primary care; (iii) putting the spotlight on quality of clinical care; (iv) aligning the response to health transition with health system strengthening; and (v) capitalizing on a favourable global policy environment. Although these proposals are aimed at primary care in sub-Saharan Africa, they may well be relevant to other regions also facing the challenges of health transition. Implementing these proposals requires action by national and international alliances in mobilizing the necessary investments for improved health of people in developing countries in Africa undergoing health transition.     

Integrated programme for noncommunicable diseases prevention and control (NCD)

In spite of the difference between developed and developing countries, health conditions change in a predictable pattern: the mortality and morbidity rates caused by infectious diseases decline while the rates related to non-infectious pathology increase. Taking into account the increasing importance of noncommunicable diseases, the majority of countries are developing a set of disease-oriented (cancer, cardiovascular diseases, diabetes, etc.) prevention and control programmes as well as factor-oriented programmes such as anti-smoking, alcohol abuse and nutrition. The Integrated Programme for Community Health in Noncommunicable Diseases, which is being developed both in WHO headquarters and in the Regional Offices, aims to amalgamate into one programme activities directed at influencing a group of risk factors common to several of the most important noncommunicable diseases. The four main directions being developed for the realization of this programme are: experimental testing, mathematical modelling, training activity and research development: At present WHO headquarters: has established 18 demonstration projects in 15 countries for experimental testing of different intervention programmes; is collecting mathematical models for prediction of efficacy and effectiveness of different alternatives and scenarios; is developing different types of training courses; is investigating the competing risk among noncommunicable diseases and time lag for different intervention programmes, etc. In order to develop all these directions many collaborating centres are participating, and close cooperation with some nongovernmental organizations has been established.(ABSTRACT TRUNCATED AT 250 WORDS)     

The global burden of oral diseases and risks to oral health

This paper outlines the burden of oral diseases worldwide and describes the influence of major sociobehavioural risk factors in oral health. Despite great improvements in the oral health of populations in several countries, global problems still persist. The burden of oral disease is particularly high for the disadvantaged and poor population groups in both developing and developed countries. Oral diseases such as dental caries, periodontal disease, tooth loss, oral mucosal lesions and oropharyngeal cancers, human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS)-related oral disease and orodental trauma are major public health problems worldwide and poor oral health has a profound effect on general health and quality of life. The diversity in oral disease patterns and development trends across countries and regions reflects distinct risk profiles and the establishment of preventive oral health care programmes. The important role of sociobehavioural and environmental factors in oral health and disease has been shown in a large number of socioepidemiological surveys. In addition to poor living conditions, the major risk factors relate to unhealthy lifestyles (i.e. poor diet, nutrition and oral hygiene and use of tobacco and alcohol), and limited availability and accessibility of oral health services. Several oral diseases are linked to noncommunicable chronic diseases primarily because of common risk factors. Moreover, general diseases often have oral manifestations (e.g. diabetes or HIV/AIDS). Worldwide strengthening of public health programmes through the implementation of effective measures for the prevention of oral disease and promotion of oral health is urgently needed. The challenges of improving oral health are particularly great in developing countries.     

A global response to a global problem: the epidemic of overnutrition

It is estimated that by 2020 two-thirds of the global burden of disease will be attributable to chronic noncommunicable diseases, most of them strongly associated with diet. The nutrition transition towards refined foods, foods of animal origin, and increased fats plays a major role in the current global epidemics of obesity, diabetes and cardiovascular diseases, among other noncommunicable conditions. Sedentary lifestyles and the use of tobacco are also significant risk factors. The epidemics cannot be ended simply by encouraging people to reduce their risk factors and adopt healthier lifestyles, although such encouragement is undoubtedly beneficial if the targeted people can respond. Unfortunately, increasingly obesogenic environments, reinforced by many of the cultural changes associated with globalization, make even the adoption of healthy lifestyles, especially by children and adolescents, more and more difficult. The present paper examines some possible mechanisms for, and WHO's role in, the development of a coordinated global strategy on diet, physical activity and health. The situation presents many countries with unmanageable costs. At the same time there are often continuing problems of undernutrition. A concerted multisectoral approach, involving the use of policy, education and trade mechanisms, is necessary to address these matters.     

Injuries and noncommunicable diseases: emerging health problems of children in developing countries.

The present article identifies, for children living in developing countries, the major causes of ill-health that are inadequately covered by established health programmes. Injuries and noncommunicable diseases, notably asthma, epilepsy, dental caries, diabetes mellitus and rheumatic heart disease, are growing in significance. In countries where resources are scarce it is to be expected that increasing importance will be attached to the development and implementation of measures against these problems. Their control may benefit from the application of elements of programmes directed against infectious, nutritional and perinatal disorders, which continue to predominate.     

Introductory lecture the epidemiology and determinants of obesity in developed and developing countries

Obesity is recognized as a serious problem in the industrialized and developed countries of the world. However, little attention is paid to the fact that obesity is becoming an increasing problem in developing countries too, with some countries showing increasing rates of obesity in the midst of the persisting occurrence of childhood malnutrition and stunting. As developing countries embrace the dominant western economic ways of development, industrialization and urbanization they contribute to improvements in living standards, with consequent dramatic changes in diets and lifestyles leading to weight gain and obesity which in turn poses a growing threat to the health. Overweight and obesity is associated with an increased likelihood of non-insulin dependent diabetes mellitus, hypertension, hyper-lipidaemia, and cardiovascular disease. It is also associated with increased rates of breast, colo-rectal and uterine cancer. Obesity is thus an important factor in the increasing morbidity and mortality due to chronic, non-communicable diseases (NCDs) and thereby contributes to premature mortality in the population. Thus, while the problem of undernutrition persists in much of the developing world, overweight and obesity and its related co-morbidities are posing an increasingly important public health problem both in the developed and developing world.     

World Health Organization global oral health strategies for oral health promotion and disease prevention in the twenty-first century

Despite great improvements in oral health in the past decades, oral disease remains a major public health problem worldwide. The burden of oral disease is particularly high among the disadvantaged population groups in both developing and developed countries. The pattern of oral disease reflects distinct risk profiles across countries that are related to living conditions, lifestyles, environmental factors, and the availability and accessibility of oral health services. In several developing countries, people at large do not benefit from preventive oral health programmes. It is expected that the incidence of dental caries will increase in the near future in many of these countries as a result of growing consumption of sugars and inadequate exposure to fluorides. With the rising use of tobacco in developing countries, the risk of periodontal disease, tooth loss and oral cancer may therefore increase. Several oral diseases are linked to non-communicable chronic diseases or conditions that share common risk factors, such as diabetes, obesity and cancer. Similarly, general diseases often have oral manifestations (e.g. diabetes or HIV/AIDS). Worldwide strengthening of public health programmes through implementation of effective oral disease prevention measures and health promotion is urgently needed, and use of common risk factors approaches should integrate oral health within national health programmes. The challenges to oral health improvement are particularly high in developing countries. The World Health Organization Global Oral Health Programme formulates policies and actions for the improvement of oral health, strategies that are fully integrated with chronic disease prevention and general health promotion. At the 60th World Health Assembly in 2007, the WHO Member States agreed on an action plan for oral health and integrated disease prevention, thereby confirming the approach of the Oral Health Programme. The policy forms the basis for future development of oral health programmes.     

Nutritional transition and non-communicable diet-related chronic diseases in developing countries

It is increasingly recognized that developing countries are undergoing an epidemiologic transition similar to that which occurred in industrialized countries in previous centuries. While infectious diseases are still the main cause of morbidity and mortality, there is a marked increase in chronic non-communicable diseases, particularly in the most advanced developing countries, and these diseases are expected to take the lead in a decade or two. Most of these diseases, above all coronary heart diseases, stroke and diabetes, are related to diet and lifestyles, for example tobacco and alcohol consumption. As a matter of fact, these societies are also facing a growing epidemic of overweight and obesity, due to the frequent energetic imbalance between energy-dense food consumption and reduced daily physical expenditure. This health transition, favoured by demographic changes towards aging populations, is occurring at an increased pace in urban societies widely exposed to the modernization of lifestyle, sedentary occupation, and to lipid- and sugar-rich food, often poor in fibre and micronutrients. Increased world access to cheaper vegetable oil is thought to have triggered off this accelerated and generalized trend, though animal food, rich in saturated fat, and imported or locally-made industrialized food also play a role. While increased national and household incomes facilitate the initial change, as the transition advances poor people progressively become the main victims, as has been observed in the more advanced developing countries. Metabolic imprinting due to intra-uterine and infant malnutrition, which are still common in these societies, is also thought to play a significant role in the increase in the expression of insulin resistance, obesity and chronic diseases when these children are exposed to abundant food and modern lifestyle, later in life. Treatment and secondary prevention of nutrition-related chronic diseases and associated disabilities have an ever rising cost in industrialized countries, which is far beyond the means of the still fragile economies of developing countries. This double burden of infectious diseases and undernutrition that still exist, and of non-communicable diseases and overnutrition represents a threat to the frequently unprepared health care services in developing countries. There is a clear need to focus health policies on the prevention of chronic diseases through primary health care services, the use of mass media for communication and education about healthy nutrition and lifestyle, and the adaptation of public policies. Nutritionists must also adapt to this changing nutritional situation which may result in apparently contradictory nutritional status findings within societies if not even within households.     

Obesity,overnutrition and the immune system

The increasing prevalence of obesity, particularly in developing countries is a major health concern due to the high risk factor that overweight and obesity represent in a number of chronic diseases such as diabetes, cardiovascular diseases and certain types of cancers. Nutritional status has an important influence on the immune system and its function is very sensitive to nutritional changes. Both under- and overnutrition are known to alter immunocompetence. While slight excess of several nutrients, specially in populations at risk of nutrient deficiencies, can stimulate immune system, excessive intake of lipids and many micronutrients is known to have adverse consequences on various components of the immune system. Obesity is associated with alteration in cellular immunity in both animal and human studies. Nutritional, metabolic and endocrine factors are implicated in the immunological changes.     

Cohort studies around the world: methodologies, research questions and integration to address the emerging global epidemic of chronic diseases

With ageing populations, increased economic prosperity and the ensuing lifestyle changes, there has been a dramatic increase in the burden of chronic non-communicable diseases in countries of the developing world. The distribution of risk factors for chronic diseases among populations in developing countries has traditionally been very different from that in their Western counterparts, thus resulting in considerable variation in disease distribution in these settings. However, with the increase in globalization along with rapid advancements in technology, many developing countries are now faced with the challenge of a dual disease burden, battling existing communicable infectious diseases as well as the emerging epidemic of non-communicable chronic diseases. This paper highlights the need for multiple cohort studies on chronic diseases around the world, and explores some of the challenges in establishing and maintaining these studies in resource-constrained settings.     

The worldwide epidemic of obesity in adolescents

There is an epidemic of obesity affecting adolescents worldwide. Both in developing and in developed countries, adolescents are increasingly becoming more obese. The number of adolescents exceeding previously identified cut-points as well as the weight and fatness of the most obese individuals is increasing at a progressive rate. Despite their benign appearance, epidemics of noncommunicable disease (or their risk factors) are no less devastating to the health of populations. The two key responses to any epidemic are to discover the causes of the epidemic disease and to characterize the epidemic. The latter needs to occur in relation to prevalence, distribution across the populations (are some population groups more likely to be affected than others?), and secular trends. This chapter reviews what is currently known about the epidemiology of overweight and obesity among adolescents throughout the world. To clarify terms of epidemiology, this chapter first identifies what are considered the most appropriate measures of adiposity and defines how much fat is too much fat.     

Drug discovery and developments in developing countries: bottlenecks and way forward

Infectious and parasitic diseases continue to threaten the health of million of people throughout the world, with the major burden being in developing countries. Many of the currently available drugs for the treatment of these diseases face setbacks such as insufficient efficacy, increasing loss of effectiveness due to emergence of resistance, high levels of toxicity, inaccessibility and/or high costs. The driving force for drug discovery and development by pharmaceutical firms has been the foreseeable profit from drug sells. Since most infectious diseases prevail in developing countries and the fact that people living in these countries have poor purchasing power, the market for such drugs are unattractive to these firms. Thus, there has been reluctance for the pharmaceutical companies to engage in the development of drugs addressing diseases that mainly affect developing countries. Although a lot of research to discover new effective and cheap drugs is in progress in the disease endemic countries, it is not yet possible to fully develop leads and drug candidates from natural products, hence people in these countries continue to rely on traditional medicines. Poor economies and technological capabilities, lack of human resources and good management in these countries are the major constraints to progress in research and development work for new drugs. This paper discusses these major bottlenecks in drug discovery and development and suggests the way forward.     

Health sector reform in South Asia: new challenges and constraints

In early 1990s, Jamison, Mosley and others concluded that a profound demographic and consequent epidemiological transition is taking place in developing countries. According to this classical model, by the year 2015, infectious diseases will account for only about 20% of deaths in developing countries as chronic diseases become more pronounced. These impending demographic and epidemiological transitions were to dominate the health sector reform agenda in developing countries. Following an analysis of fertility, mortality and other demographic and epidemiological data from South Asian and other developing countries, the paper argues that the classical model is in need of re-evaluation. A number of new 'challenges' have complicated the classical interplay of demographic and epidemiological factors. These new challenges include continuing population growth in some countries, rapid unplanned urbanization, the HIV/AIDS pandemic in Sub-Saharan Africa (and its impending threat in South Asia), and globalization and increasing marginalisation of developing countries. While the traditional lack of investment in human development makes the developing countries more vulnerable to the vicissitudes of globalization, increasing economic weakness of their governments forces them to retreat further from the social sector. Pockets of poverty and deprivation, therefore, persist giving rise to three simultaneous burdens for South Asia and much of the rest of the developing world: continuing communicable diseases, increasing burden of chronic diseases, and increasing demand for both primary and tertiary levels of health care services. While these complex factors, on the one hand, underscore the need for health sector reform, on the other, they make the task much more difficult and challenging. The paper emphasizes the need to revisit the classical model of demographic and epidemiological transition. It is argued that the health sector in developing countries must be aware of and effectively address these 'new challenges'. Although it has included data from many developing countries, the focus is primarily on South Asia.     

Contribution of nutrition to the health transition in developing countries: a framework for research and intervention

The major focus of public health programs in developing populations is alleviating undernutrition. In South Africa, however, as in many other developing countries, the African population is experiencing rapid urbanization characterized by a double burden of disease in which noncommunicable diseases (NCD) become more prevalent and infectious diseases remain undefeated. The possible mechanisms through which nutrition contributes to the additional vulnerability to NCD experienced by developing populations are explored and research priorities in this area are identified.