Challenges in Public Heath

Challenges in Public Health

Unfortunately, in the modern world, interpersonal violence and war have become common. In some segments of society (particularly among adolescent and young adult minority males), violence has become the leading cause of death and productive years of life lost. Public health cannot ignore the fact that violence and wars are major factors dramatically reducing the quality of life for millions.

Many of the advances in public health have become possible through research. The research will continue to be essential for identifying and anticipating health problems and the optimal strategies for addressing them. Strategies that seem very logical may, in fact, not succeed for a variety of unforeseen reasons. Therefore, public health systems and programmes cannot be assumed to function cost-effectively without continuous monitoring and evaluation. Thus, it is essential that new public health strategies undergo rigorous evaluation before being scaled up, and once scaled up, are periodically reviewed to ensure their continuing effectiveness in diverse groups and populations.

Over the last century, the quality of research has been enhanced by the development of new methodologies, particularly in the fields of epidemiology, biostatistics, and laboratory sciences. Rapid advances in computational hardware and techniques have increased our ability to analyse massive amounts of data and to use multiple strategies to aid in the interpretation of data. Despite this, it will be a major challenge to keep pace with the explosive growth in the volume and complexity of data being generated, driven by a range of factors from the pervasive use of the Internet, social media, and mobile phones, to the masses of data from molecular biology and sequencing studies. Glean valuable insights pertinent to public health from these huge datasets will require new approaches, strategies, and methodologies. It is essential that public health continues to use leading-edge technologies to develop more sophisticated research strategies to address public health issues.

From poverty to disease

Underlying the bulk of the public health problems of the world is the issue of poverty.  More than half of the world’s population lives below the internationally defined poverty line, and 22 per cent of the population in developing countries lives on less than the US $1.25 per day based on the report published by World Bank in 2012. Although the majority of the worlds poor live in developing countries, there are many poor livings in the wealthiest countries of the world—underscoring the disparity of wealth between the poor and the rich in all countries.

Top 10 causes of death worldwide

By 1980, many leading public health figures felt that infectious diseases had been eliminated as a primary concern for public health; however, the discovery and expanding the pandemic of AIDS (Acquired Immuno-deficiency Syndrome caused by the HIV (Human Immunodeficiency Virus) in the early 1980s, and subsequently, the SARS (Severe Acute Respiratory Syndrome) outbreaks in the early 2000s demonstrated the fallacy of their thinking, as do the persisting high rates of infectious diseases, particularly in Africa.

Although communicable diseases persist as a major public health concern, globally chronic non-communicable diseases have become the major health problem, accounting for 70 per cent of deaths. Even in poor, developing countries, Non-communicable diseases are a dominant and growing challenge. 

Nearly 80 per cent of the deaths due to non-communicable or chronic diseases in 2008 occurred in developing countries, in part because many more people live in low- and middle-income countries than in high-income countries as per WHO Report in the year 2011. The age-standardized death rate due to Non-communicable diseases among males in low- and middle-income countries was 65 per cent higher, and among females, 85 per cent higher than for men and women in high-income countries. This figure is particularly disturbing because low- and middle-income countries have far fewer resources and capacity to address the epidemic of Non-communicable diseases. Communicable diseases, however, still accounted for 30 per cent of the burden of disease worldwide but caused most deaths only in Africa. Many communicable diseases are now preventable through vaccines, improved sanitation, behavioural interventions, and better standards of living.

Global trends in causes of death

Leading causes of early death, 1990 and 2017: Ischemic heart disease, neonatal disorders, stroke, lower respiratory infections, diarrhoea, road injuries, and COPD (Chronic Obstructive Pulmonary Disease (COPD) accounted for more than 1 million deaths each worldwide in 2017.

Between 1990 and 2017, early death from enteric infections, respiratory infections and tuberculosis, and maternal and neonatal disorders dropped, with the greatest declines in the least developed countries. Progress in reducing mortality from some common diseases has stalled or reversed, primarily for non-communicable diseases such as cardiovascular diseases and cancers. An unintended consequence of greater access to health care globally is increasing in mortality from diseases and disorders linked to antibiotic resistance.

World Population Ageing

This graph gives us a better understanding about the proportion of the global population – 60 years or older from the year 1950 to 2050 as per the report published by United Nations.

Compounding the global shift to Non-communicable diseases is the rapidly rising age of populations in many countries due to increased longevity and dramatically decreased birth rates.

Population growth is already below replacement in many countries, both developed and developing. This demographic shift has widespread and profound implications. It will increase the burden of chronic disease in these countries, place increasing demands on healthcare and social support services, and strain public financing systems.

This will occur even as the proportion of the population in the productive ages will decrease, which in turn will impact economic growth. The low- and middle-income countries will be affected by the ageing of their populations.

Measuring disease occurrence

An essential step in defining health is to identify appropriate methods for measuring it. Traditionally, public health has defined disease in terms of mortality rates because they are relatively easy to obtain and death is indisputable. The use of mortality rates, however, places the greatest emphasis on diseases that end life, and tends to ignore those which compromise function and quality of life without causing death. Thus, the problems of mental illnesses, accidents, and disabling conditions are seriously underestimated if one uses only mortality to define health.

Two other strategies to measure health that evolved in the last half of the twentieth century have been ‘Years of Productive Life Lost’ (YPLL) and ‘Disability-Adjusted Life Years’ (DALYs). The former emphasizes those diseases that reduce the productive lifespan (currently arbitrarily defined as 75 years), whereas the latter emphasizes those diseases that compromise function but also includes a measure of premature mortality. Using either of these alternatives to define health results in quite different orderings of diseases and/or health problems as public health priorities.

Using death to identify disease priorities, the leading cause is Non-communicable diseases, which account for 70 per cent of diseases worldwide. Among the chronic diseases, cardiovascular diseases account for half of the deaths. The proportion, however, varies markedly by regions of the world and level of affluence of the countries. Communicable diseases remain the major cause of death only in Africa, although they account for a significant proportion of deaths in South East Asia and the eastern Mediterranean. The major victims of these communicable diseases are infants and children under 5 years old. The persistence of communicable diseases in these areas represents a continuing major public health challenge.

Communicable Diseases

Many new vaccines against infectious agents have been and are being developed and many have become more affordable. The WHO’s regional offices working with individual countries have conducted intensive immunization programmes against the major preventable infectious diseases of childhood, but there are significant barriers to complete coverage, including poverty, geographic obstacles, low levels of education affecting willingness to accept vaccination, logistical problems, civil unrest and wars, corruption, and mistrust of governments. Poverty, weak governments, and misuse of funds have also prevented the control of disease vectors that play a key role in diseases such as malaria and dengue, provision of clean water, and safe disposal of sanitation, all essential for the control of communicable diseases.

Another major factor in the rapid spread of communicable diseases has been the rapid growth in transportation. It is now possible for an individual with a communicable disease to circumnavigate the globe while still infectious and asymptomatic. Similarly, due to the extensive global food supply chains, food-borne infections can spread rapidly within and across countries. Another source of communicable diseases is the continuing emergence of new infectious agents, many of them adapting to humans from animal sources. Changes in food production, crowding of animals, mixing of live animal species in ‘wet markets’ (selling live animals for food) in Asia and elsewhere, and the introduction of hormones and antibiotics into animal feed have all contributed to the emergence of these new diseases.

Newly identified infectious diseases and pathogens

This slide lists many of the new diseases that have been recognized since 1980.

In the next slide, we will be discussing the list of factors that contribute to the emergence of these new agents and disease threats. In addition to the diseases listed in the slide, antibiotic-resistant strains of known agents have emerged rapidly due, in part, to the widespread inappropriate use of antibiotics. Thus, resistant strains of gonorrhoea, Staphylococcus, tuberculosis and malaria have become major problems. The latter two have now emerged as two of the three current major infectious disease problems globally. The development of drug-resistant malaria has been compounded by the emergence of vectors resistant to the commonly used chemical insecticides.

List of factors contributing to the emergence/re-emergence of infectious diseases:

Approximately 1 billion people, one-sixth of the world’s population, suffer from one or more tropical disease, including Buruli ulcer, Chagas’ disease, cholera, dengue, dracunculiasis, trypanosomiasis, leishmaniasis, leprosy, lymphatic filariasis, onchocerciasis, schistosomiasis, helminthiasis, and trachoma as per WHO report published in 2006. The functional ability of those so afflicted is severely compromised, in turn affecting the economic competitiveness of the poorest countries, which suffer the greatest burden of these tropical diseases. However, major strides have been achieved in reducing the burden of diseases such as leprosy, guinea worm disease, and lymphatic filariasis. Continuing efforts are needed to further reduce the burden of these and other tropical diseases. We now recognize that we will continue to see new human pathogens emerging in the future and need to be prepared to contain them. Unless the world realizes the consequences of not protecting the environment in which we live, and acts on it, newly emerging diseases will continue to plague us.

Non-communicable diseases

Non-communicable diseases are the world’s top-most killer, bringing hardship to rich and poor nations alike. Non-communicable diseases, such as heart disease, cancer, chronic respiratory disease, and diabetes, are the leading cause of death worldwide and represent an emerging global health threat. Deaths from Non-communicable diseases now exceed all communicable disease deaths combined. Non-communicable diseases kill 41 million people each year, equivalent to over 7 out of 10 deaths worldwide. Changing social, economic, and structural factors such as more people moving to cities and the spread of unhealthy lifestyles have fuelled the NCD crisis that kills 15 million people prematurely—before the age of 70—each year.

Non-communicable diseases make the largest contribution to mortality and account for 60% which is around 35 million global deaths. The largest burden - 80% which means 28 million - occurs in low- and middle-income group countries, making Non-communicable diseases a major cause of poverty and an urgent development issue. They will be the leading global cause of disability by 2030.

With increasing control of communicable diseases and increasing lifespan, Non-communicable diseases have emerged as the major global health problem in both developed and developing countries. Even in developing countries, Non-communicable diseases have assumed greater importance. The prevalence of type 2 diabetes in rural India is 13.2 per cent. Cardiovascular diseases have become a major cause of death in China. The causes of Non-communicable diseases are many and complex. Although the immediate causes are factors such as raised blood pressure, increased blood glucose, abnormal lipids and fat deposition, and diabetes, the underlying causes are behavioural and social. These behavioural factors include unhealthy diets that substitute pre-packaged and fast foods high in fats for a balanced diet, physical inactivity, and, especially, tobacco use; these, in turn, are the products of social change, including globalization, urbanization, and ageing.

Globally, the NCD burden will increase by 20% in the next ten years, and in the African region by 30%. This rapidly changing health and disease profile have serious implications for poverty reduction and economic development. Non-communicable diseases strangle macro-economic development and keep the bottom billion locked up in chronic poverty. Non-communicable diseases have a severe impact on individuals, communities, and countries. The magnitude and rapid spread of Non-communicable diseases mean we are all headed for a sick future unless we act now. Low-income countries still grappling with heavy burdens of infectious disease risk being overwhelmed by this wave of largely preventable Non-communicable diseases.

Another aspect of Non-communicable diseases are the increasing survival of affected individuals who would not have survived as long previously. However, many of them are left with disabilities that require modified environments to experience a reasonable quality of life and to realize their full potential to contribute to society. Most Non-communicable diseases can be reduced by a combination of healthy behaviours, including not smoking, moderate alcohol use, and exercise. Many developed countries have been promoting healthy lifestyles, but there is a need for greater emphasis and development of these programmes in developing countries, where the major global burden of chronic diseases occurs.

Mental illness and Population projections

Mental Illness: Mortality rates seriously underestimate the burden of mental health on society. The true extent of mental illness is probably greater—only 60 per cent of countries report having a dedicated mental health policy and only 27 per cent report data on expenditures for mental health. Global provisions for the treatment of a mental illness are still significantly below what is necessary to adequately address the problem. In developing countries, only US $0.25 is allocated per patient for mental health and there is less than one psychiatrist per 200,000 persons. Of those with mental illness in developing countries, 76–85 per cent do not have access to appropriate care. Although 87 per cent of the world’s governments offer some mental health services at the primary care level, 30 per cent of them have no relevant programme, and 28 per cent have no budget specifically identified for mental health. Mental illness robs society of a significant number of potentially productive persons. With the diminishing proportion of productive people of working age and the increasing proportion of elderly dependents, it is important to assist those who are not productive because of mental illness to become healthy, productive members of society.

Population projections: The occurrence of disease in old age is directly correlated with unhealthy behaviours developed in early life. Unfortunately, concurrent with population growth, there has been a worldwide epidemic of obesity and decreased physical activity, which has increased the proportion of elderly who suffer from chronic debilitating diseases in both the developed and developing world. Thus, unless efforts to promote healthy lifestyles are successful, not only will there be an increase in the proportion of elderly, but also an increasing proportion of them will require assistive care, placing a further economic and social burden on families and society. As the population grows, there is increasing pressure to provide food, water, and other necessities to maintain a high quality of life. Shifts in dietary preferences in developing countries towards greater meat consumption also put additional strains on food production. Fertile farmlands are increasingly being converted to residential, commercial, or industrial use. Thus, more people will effectively need to be supported on less arable land. Food security will hence be a key issue for the future, and this will be affected by a multitude of factors but most notably sufficiency of water resources and whether there will be major increases in agricultural productivity.

Other public health issues

Nutrition: Appropriate nutrition is essential for health. In many developing countries (as well as among the poor and homeless in developed countries), undernutrition is a problem. Beyond access to nutritious and safe food, many of the poor have little knowledge about what constitutes a healthy diet, compounding the difficulties. At the same time, in developed and many rapidly developing countries such as China, overnutrition and obesity are major problems.

Oral health: Good dental health is essential for maintaining adequate nutrition and good quality of life. Worldwide, however, 60–90 per cent of school children and nearly 100 per cent of adults have dental cavities. About 30 per cent of adults aged 65–74 years have no natural teeth. It was also estimated in 2004, that globally, there was an average of 1.6 decayed, missing, or filled teeth (DMFT) among children aged 12 years old as per WHO report in 2004. These high rates of dental problems reflect poor dental hygiene and preventive care. Unfortunately, many people believe that dental care is an expendable luxury and that visits to dentists are only necessary when there is a problem. Oral cancers are the sixth most common cause of cancer globally, with a 5-year prevalence estimated to be 6.8 per cent globally. Poor dental hygiene is an important risk factor, together with smoking as well as the habit of betel nut chewing which is common in parts of Asia. Clearly, the public health message regarding the importance of good dental hygiene, regular tooth-brushing, and regular dental check-ups is not reaching most people. 

Injuries: Injuries and violence caused 5.8 million deaths in 2011, of which 1.6 million were due to global violence, 1.3 million to traffic accidents, and 844,000 to suicide. Deaths due to injuries are almost three times greater in developing than in developed countries. However, most of the injuries do not cause death but may result in disability. Furthermore, they occur more commonly among younger persons and children. Injuries can be broadly categorized into the following groups: motor vehicle accidents, suicide, homicide, and unintentional injuries, including occupational injuries and falls. Motor vehicle accidents account for the largest proportion of deaths due to injury. The WHO projects that motor vehicle accidents will become the third highest cause of DALYs globally by 2020. Falls, particularly among the elderly, are a major cause of DALYs as well. Unintentional injuries are largely preventable through community and governmental intervention. Thus, improved roads, separation of different modes of transportation, enactment and enforcement of seat belt and helmet laws, and improved designs of automobiles, ladders, and other equipment and tools have all been shown to significantly reduce injuries and deaths due to accidents.

Homicide, violence, and suicide: Homicide, violence, and suicide represent a growing problem, particularly among the young. Homicide and suicide are among the leading causes of death globally. In some minority groups in the United States, homicide and violence are the leading cause of death of youth, followed by suicide. In China, suicide remains the leading cause of death among women in rural areas. Globally, the WHO predicts that homicide and suicide will account for an increasing proportion of deaths. The WHO predicts that by 2020, war will become the eighth highest cause of DALYs, violence (including gender-based and personal) the twelfth, and self-inflicted injuries the fourteenth.

Vulnerable populations: Public health has always been concerned with the health and well-being of vulnerable groups who require special attention. The definition of a vulnerable population varies by time, situation, and culture, but the common characteristic across all vulnerable groups is their special susceptibility to adverse health and poor quality of life. The list of vulnerable groups includes the poor, minorities, women, children, the elderly, the handicapped, the illiterate, orphans and street children, immigrants, rural-to-urban migrants, refugees, and displaced people, the homeless, and the mentally ill. In certain situations, other groups may be considered vulnerable. For example, in the face of epidemics such as HIV/AIDS, one should also consider adolescents to be a vulnerable group. Often vulnerable individuals live at the margins of society and have difficulty accomplishing the basic functions of living and accessing healthcare. Thus, they require assistance. In many societies, particularly in developing countries, the family acts as the safety net for these groups, but if the family itself is vulnerable or dysfunctional, this safety net is absent. Societies with ample resources have developed social support programmes that assist the vulnerable, but these programmes seldom cover the full range of vulnerable groups and may not adequately support those whom they target. Universal access to healthcare is one component of assisting the vulnerable, but presently, even in rich, developed countries such as the United States, healthcare is not available to all, and strategies to fund universal healthcare are difficult to implement.

In almost every country, developed and developing, there are homeless people, many of whom suffer from multiple problems, including mental illness. The ability to function adequately and achieve good health among many vulnerable groups, including the homeless, mentally ill, alcoholics, and drug addicts, is adversely impacted by additional factors such as poverty, prejudice, and stigmatization by society. Thus, programmes to assist the vulnerable need to also encourage society to take supportive action, to be optimally effective. This is a particular challenge with respect to persons with handicaps.

Many developed countries have adequate provision for persons with handicaps, but in poorer countries, those with handicaps face substantial difficulties to function in society, and many do not survive. In designing programmes for vulnerable groups, a further complication is a fact that the specific problems and needs of each of these groups differ, and they thus require public health actions that are more tailored to their requirements. For some of these groups, such as mothers and children and the handicapped, there are well-established programmes, although coverage is far from complete and the quality of these programmes varies widely. For others, such as the illiterate and migrants, there are fewer established programmes. If we are to meet the public health goal of ‘Health for All’, we need to identify and assist the vulnerable groups within societies to achieve their maximum possible health and function.

The environment: Currently, one of the major problems which the world faces is the deterioration of the environment caused by the increasing numbers of people and the accumulation of wastes produced by them, their vehicles, and the industries they support. Thus, the quality of the air that we breathe has declined, especially in developing countries where rapid economic growth has been achieved at the expense of the environment. The most polluted cities of the world are concentrated in developing countries, which often have the least capacity and political will to reduce pollutants. Pollution of the world’s oceans, which receive massive amounts of biological and chemical wastes annually, affects not only the quality of the water but also the ability of the ocean to sustain marine life, an important source of food. Problems of the environment occur at the personal level (at home and the workplace), the community level (example - air and water pollution), and globally (example - global warming, hazardous and radioactive waste). Although these problems may be viewed separately, they are in fact all global issues affecting both local and remote populations.

Air pollution: The rapid increase in automobiles and industry has caused widespread air pollution in most urban areas of the world, the worst occurring in the developing countries, which have rapidly industrialized at the expense of their environment. Now, in the early part of the twenty-first century, many of these countries are realizing the need to protect the environment. Unfortunately, the reversal of decades of pollution is far more difficult and costly than prevention. The harmful effects of air pollution extend beyond the environment. Many members of society, including asthmatics and persons with chronic respiratory disease, are vulnerable to even relatively low levels of pollutants. Levels of pollutants observed in many developing countries, especially in China and India, are considerably higher than in developed countries. Studies have documented the serious health effects of long-term exposure to the levels of pollutants occurring in China. However, the true cost of uncontrolled industrialization and pollution in these countries is not known. Indoor pollution is a particular problem in developing countries where cooking is traditionally carried out using coal or charcoal fires in poorly ventilated houses. However, it is also a problem in wealthier countries in which harmful chemicals are used for cleaning and household construction. 

Water pollution: Those who live in developed countries take the provision of safe drinking water for granted, but 40 per cent of the world’s population does not have access to clean drinking water, a necessity of life. As the world population expands, the production of waste increases and the problem of protecting water supplies also rises. Approximately 60 per cent of the world does not have adequate facilities for waste disposal. Even in leading cities in developed countries, pollution of the water supply can occur, as happened in Milwaukee, Wisconsin, when cryptosporidia contaminated the water supply, causing severe illness and death, especially in vulnerable populations compromised by immune deficiency disorders. The increased rate of upper respiratory infections and gastrointestinal disorders among surfers and others using the ocean for recreational purposes has been well documented. Beaches in most urban areas are frequently closed when the sewage disposal systems that drain into the vicinity become overwhelmed. Acid rain from industrialization has caused acidification of lakes, making them inhospitable for fish and other marine life, thus compromising the food supply. Recently there has been discussion about whether the benefits of omega-3 fatty acids found in fish outweigh the risk of mercury poisoning among those who eat large quantities of fish. Ensuring a safe, adequate water supply for people in both developed and developing countries must become a public health priority.

Other pollutants: As the population of the world rapidly increases and technology produce new substances and processes, not only the number of pollutants but also the varieties of pollutants increase. As new substances are developed, it would be ideal if their use is not permitted until plans and provisions have been developed and implemented for their safe disposal. However, this is often not the case in practice. Biodegradable pollutants have a limited lifespan in the environment, but we are increasingly producing non-biodegradable substances such as plastics, which are now ubiquitous, and hazardous materials such as radioactive wastes that persist for generations. The problem of discarding these materials safely has become a major public health issue. In some cases, developed countries are paying developing countries to accept their hazardous waste products. This strategy does not solve the problem but shifts it to those countries that have fewer resources with which to deal with the challenge. In the last decade, nanoparticles (1 nanometre is 1 billionth of a metre) have been increasingly used in the production of foods, drugs, cosmetics, and other products used by humans. Particles of this small size become reactive in the body and, according to recent reports, can cause serious damage to lung cells, the liver, and brain cells. Given this problem, it is important that the use of nanoparticles in products intended for human use be regulated.

Climate change: One of the most serious, long-term challenges of the twenty-first century is global warming due to the release of carbon dioxide and other ‘greenhouse gasses. There is growing evidence that consequential climate change will be associated with increased public health risks. A major review by WHO to assess the public health impact of anthropogenic climate change to date estimated that from 1975, climate change might already have contributed to 150,000 deaths and about 5 million DALYs per year. These are largely related to the increased incidence of conditions such as malnutrition, diarrhoea, and malaria. Mitigating the health impact of global warming and climate change at the regional level will be a major public health issue for this century.

Rescuing the environment: To prevent further degradation of the environment and to tackle the threat of global climate change, strong political will is required of the countries of the world. For example, while the United States is one of the world’s major producers of carbon dioxide and other greenhouse gases, it has yet to ratify the United Nations Framework Convention on Climate Change, an international treaty aimed at stabilizing global greenhouse gas at levels that would avoid dangerous climate change. From a public health perspective, it is unrealistic to expect that the risks from environmental pollution and hazardous waste can be reduced to zero. Instead, the concept of ‘acceptable risk’ will continue to be a part of the process. Determining the level of acceptable risk will probably be arrived at through an interplay of the scientific data and evidence, with policy and political judgements. Public health professionals and researchers must endeavour to play a strong role in these determinations.