Concepts of Poverty and Health

Poverty is a multidimensional phenomenon that can be defined in both economic and social terms. An economic measure of poverty identifies an income sufficient to provide a minimum level of consumption of goods and services. A sociologic measure of poverty is concerned not with consumption but with social participation [2]. Poverty leads to a person's exclusion from the mainstream way of life and activities in a society [3]. There is a difference between absolute poverty, which implies a lack of resources deemed necessary for survival in a given society, and relative poverty, which is defined in relation to the average resources available in a society. Economic measures are easy to obtain, but social measures may provide a better understanding of the causes and consequences of poverty. Steps have been taken toward the development of indices of deprivation, which have promising uses in health services and public health research [4].

In 1978, the World Health Organization (WHO), in the Alma-Ata Declaration, spelled out the dependence of human health (defined broadly) on social and economic development and noted that adequate living conditions are necessary for health [5]. Despite their knowledge of this, governments and major development organizations have largely continued to view health narrowly as a responsibility of the medical sector, outside the scope of economic development efforts. Consequently, governments have encouraged many large-scale but narrowly focused economic development efforts, ignoring the connection between poverty and health [6]. In developed countries, governments promote various practices, such as heavy pesticide applications, that are designed to increase economic development and competitiveness but that are environmentally unsound and personally unhealthy.

Poverty Causes Death and Illness on a Massive Scale

During the second half of the 1980s, the number of persons in the world who were living in extreme poverty increased. Currently, extreme poverty afflicts more than 20% of the world's population. A recent report from WHO points out that up to 43% of children in the developing world-230 million children-have low height for their age and that about 50 million children have low weight for their height [7]. Micronutrient malnutrition (deficiencies of vitamin A, iodine, and iron) affects about 2 billion persons worldwide.

It has been estimated that if developing countries enjoyed the same health and social conditions as the most developed nations, the current annual toll of more than 12 million deaths in children younger than 5 years of age could be reduced to less than 400 000. An average person in one of the least developed countries has a life expectancy of 43 years; the life expectancy of an average person in one of the most developed countries is 78 years [7]. This is not to deny that real gains in health have occurred in recent decades. For example, since 1950, life expectancy at birth in several developing countries has increased from 40 to more than 60 years. Similarly, worldwide, mortality rates for children younger than 5 years of age decreased from 280 to 106 per 1000, on average. Some countries show much sharper declines [7], but indices of health in these countries still fall far short of those in wealthier nations.

Poverty and Sustainable Development

The relation between poverty and health is complex, and we believe that it is best understood in the framework of a new notion of "ecosystem health," which places poverty and health in the nexus of environment, development, and population growth [8]. Ecosystems provide the fundamental underpinning for public health in both developed and less developed countries, not only through food production, for example, but also through their roles in economic development. For instance, they supply forest resources and biomass fuels and serve as habitats for the vectors of disease [9]. Sustainability is produced by using resources in ways that meet the needs of current populations without compromising the ability of future generations to meet their own needs [10] and is predicated on the need to ensure a more equitable sharing of today's resources. Meeting the needs of the world's poor implies limitation of the current use of resources by industrialized nations.

Barriers to the benefits of development include rapid population growth, environmental degradation, and the unequal distribution of resources. At one extreme, traditional, preindustrial societies are characterized by relatively high birth rates coupled with high death rates attributable to acute infectious diseases and the hazards of childbearing; this leads to slow population growth. At the other extreme, in the most developed countries, population stability has occurred. In the intermediate situation, in less developed countries, population stability has not been reached, and the global population thus continues to increase. In some less developed countries, a "demographic trap" exists in which the development of resources cannot keep pace with the requirements of the growing population and poverty is worsened [11]. The most developed countries escape the trap by buying additional essential resources in the global marketplace to make up the difference.

Environmental degradation exaggerates the imbalance between population and resources, increases the costs of development, and increases the extent and severity of poverty. For example, the need for fuel wood, timber for export, and farmland results in deforestation, which increases soil erosion, flooding, and mud slides and reduces agricultural productivity. As a result, biological diversity is lost, production becomes increasingly reliant on pesticides and fertilizers, and use of expensive fossil fuels increases. Water is a critical resource. In Punjab, the breadbasket of India, the major aquifer is decreasing at a rate of 20 cm per year, threatening health by reducing agricultural productivity and the supply of clean water [12]. Economic development without regard to long-term environmental and social consequences also threatens sustainability by damaging the systems that sustain healthy communities.

Inequalities in Health Are Socially Determined

The strong and pervasive relation between an individual person's place in the structure of a society and his or her health status has been clearly shown in research conducted over the past 30 years [13-16]. In 1973, Kitagawa and Hauser [17] published convincing evidence of an increase in the differential mortality rates according to socioeconomic level in the United States between 1930 and 1960. They found that rates of death from most major causes was higher for persons in lower social classes. In Britain, research into health inequalities was summarized in 1980 in The Black Report [18], which was updated in 1992 [19] and is currently under review by an official working group. The report was prepared by a labor government-appointed research working group chaired by Sir Douglas Black, formerly Chief Scientist at the Department of Health and, at the time, President of the Royal College of Physicians. The Black Report concluded that "there are marked inequalities in health between the social classes in Britain" (Figure 1). Marmot and colleagues, in the well-known Whitehall studies of British civil servants begun in 1967, showed that mortality rates are three times greater for the lowest employment grades (porters) than for the highest grades (administrators) and that no improvement occurred between 1968 and 1988 [20-22].

View larger version (14K): [in this window] [in a new window]   Figure 1. Comparison of standardized mortality ratios for men 15 to 64 years of age by social class over five decades in England and Wales. Figures have been adjusted to the classification of occupations used in 1951. Information on men 20 to 64 years of age in Great Britain was obtained from Black and colleagues [18].

Such findings could, in theory, be due to differences in age, smoking, nutrition, types of employment, accident rates, or living conditions, but the Whitehall study participants were from a relatively homogeneous population of office-based civil servants in London. They had largely stable, sedentary jobs and access to comprehensive health care. A second observation of the Whitehall investigations, confirmed by the Multiple Risk Factor Intervention Trial (MRFIT) studies in the United States, is that conventional risk factors (smoking, obesity, low levels of physical activity, high blood pressure, and high plasma cholesterol levels) explain only about 25% to 35% of the differences in mortality rates among persons of different incomes (Figure 2) [23, 24].

View larger version (27K): [in this window] [in a new window]   Figure 2. Income and age-adjusted mortality rates among 300 000 white men in the United States. Data obtained from Smith and colleagues [23].

An equally striking finding is Wilkinson's observations of the relation between income distribution and mortality [25, 26]. Wilkinson assembled two sets of observations. First, he found no clear relation between income or wealth and health when comparisons were drawn between countries (for example, there is no relation between per capita gross domestic product and life expectancy at birth in comparisons between developed countries at similar levels of industrialization). But Wilkinson also showed a strong relation between income inequality and mortality within countries, a relation that has been confirmed more recently [27, 28]. The countries with the longest life expectancy are not necessarily the wealthiest but rather are those with the smallest spread of incomes and the smallest proportion of the population living in relative poverty. These countries (such as Sweden) generally have a longer life expectancy at a given level of economic development than less equitable nations (such as the United States).

Recent analysis of U.S. data supports earlier observations that the distribution of wealth within societies is associated with all-cause mortality and suggests that the relative socioeconomic position of the individual in U.S. society may be associated with health. Populations in U.S. states with income distributions that are more equitable have longer life expectancies than do those in less egalitarian states, even when average per capita income is taken into account [27, 28]. Authors of the studies that revealed these findings recently introduced the notion of "social capital," which is defined as civic engagement and levels of mutual trust among community members, as an important variable intervening between income inequality and health status [29]. Evans and associates [15] suggest that one's control of the work environment is an important connection between social and occupational class and mortality.

The Robin Hood index, also known as the Pietra ratio, is used to estimate the percentage of total income that would have to be transferred from groups above the mean to groups below the mean to equalize income distribution. A higher Robin Hood index value represents greater disparity in incomes. The strong correlation between income distribution and mortality rates shows that income disparity, in addition to absolute income level, is a powerful indicator of overall mortality (Figure 3) [27].

View larger version (13K): [in this window] [in a new window]   Figure 3. Age-adjusted mortality in the United States in 1990 and the Robin Hood index of income inequality. Circles represent the states of the United States. Data were not available for New Mexico, Rhode Island, and Virginia. Adapted from Kennedy and colleagues [27] with permission.

Inequalities in Income and Health Are Worsening

Many of the improvements in life expectancy and infant mortality rates that have occurred around the world are overshadowed by the countervailing influence of increasing disparities between rich and poor. Since 1980, economic decline or stagnation has affected 100 countries, reducing the incomes of 1.6 billion persons [19]. Between 1990 and 1993, the average income decreased by 20% or more in 21 countries, particularly countries in eastern Europe and the countries of the former Soviet Union [30]. The net worth of the world's 358 richest persons is equal to the combined income of the poorest 45% of the world's population: 2.3 billion persons. Between 1960 and 1991, the ratio of the global income of the richest 20% of the world's population relative to the poorest 20% increased from 30:1 to 61:1 [30, 31].

Many recent improvements in population health have been threatened and, in some cases, reversed at the same time that income differentials have widened. For example, the proportion of underweight children in Africa may decrease from 26% in 1990 to 25% in 2005, but the total number of underweight children is projected to increase from 31.6 million to 39.2 million because of population growth.

In the United States and the United Kingdom, income distribution has become more unequal. According to the United Nations Development Programme, income distributions within each of these countries are now among the most unequal distributions in the world's industrialized countries [31, 32]. For example, in the United Kingdom, the proportion of persons with an income less than half of the national average increased from less than 10% in 1982 to more than 20% in 1993, and unskilled men in Scotland now have a mortality rate three times that of professional men [33]. This represents a widening from a twofold differential in the early 1970s. In the United Kingdom, the difference in mortality rates between rich and poor has increased because mortality rates have decreased faster among the rich than among the poor [34], and the proportion of children below the official poverty line has tripled in the past 10 years [35, 36]. In the United States, inequality in income increased in all states except Alaska between 1980 and 1990 [37].

Effective Interventions Reduce Ill Health Due to Poverty

Some evidence suggests that improving the income of the poorest persons improves health in both developed and less developed countries. International data have been used to show that the doubling of per capita income (adjusted for purchasing power parity) from $1000, using 1990 figures, corresponds to an increase of 11 years in life expectancy. The relation flattens off above an average per capita income of approximately $5000 (Figure 4) [30]. The distribution of income within households also influences health. It has been suggested, for example, that it takes 10 times more spending to achieve a given improvement in child nutrition in Guatemala when income is earned by the father than when it is earned by the mother because the mother is more likely to spend the money on essentials for the family [30].

View larger version (18K): [in this window] [in a new window]   Figure 4. Life expectancy at birth and gross national product (GNP) in 1970 and 1995 in rich and poor countries in 1990 U.S. dollars. Triangles represent life expectancy in 1970; diamonds represent life expectancy in 1995. Data obtained from World Development Indicators, World Bank, 1995.

An important, possibly unique, randomized trial in Gary, Indiana, suggests that increasing the income of poor expectant mothers receiving welfare increased the birthweight of their babies [38]. Education, particularly for mothers, has dramatically affected health. In Peru, for instance, the children of mothers with 7 or more years of education have a reduction in child mortality of nearly 75% compared with the children of mothers with no schooling. Studies in several countries have shown that mothers who have completed secondary or higher education are much more likely to treat childhood diarrhea appropriately with oral rehydration therapy. Families are also likely to be smaller when women are more educated [30].

A recent systematic review of the effectiveness of health service interventions, predominantly in industrialized countries, to reduce poverty-related inequalities in health suggests several characteristics of interventions that may be successful, although they do not directly affect income [39]. These include programs that target high-risk groups; outreach programs that include home visits; and programs that overcome barriers to the use of services by providing transportation or convenient access and by using prompts and reminders. Large-scale multidisciplinary interventions involving a range of agencies and programs may be cost-effective. The Special Supplemental Food Program for Women, Infants and Children (WIC) was initiated in 1972 in the United States and provides healthy food, education about nutrition, and health services to low-income women and their children. Data analysis suggests substantial reductions in the number of babies with low and very low birth weights as a result [40]. The project paid for itself through equivalent savings in medical care. Project Head Start provides preschool children and their families with education, health care, and social services. Short- and long-term benefits have been shown in health, developmental, and social outcomes [41].

Economic analysis confirms that primary care interventions, including measures designed to reduce childhood malnutrition, improve immunization against childhood diseases, provide chemotherapy against tuberculosis, provide condoms and education to combat the spread of HIV, and reduce smoking (including consumer taxes on tobacco) are cost-effective [42].

Physicians Have Special Responsibilities

It is widely accepted that physicians have a special and central professional responsibility to treat disease and reduce mortality rates, a responsibility that arises from their knowledge of medicine and medical practice [43]. The physician-patient relationship is a fiduciary one, based on the inherent responsibility of physicians to deserve the trust of patients. Professionalism also extends this relationship to society, which confers on the profession respect and certain kinds of autonomy and authority. In the context of the physician-society relationship, the physician's fiduciary responsibility takes the form of concern for the public health. Most major traditions of medical ethics suggest that physicians have a special responsibility for the care of poor persons, defined as those who cannot afford to pay for treatment [44].

In addition, physician responsibilities in patient care extend to the social context of health and disease. Physicians regularly attempt to influence both patients' lifestyles and their environments to help prevent illness. They do so because illness is often precipitated by behavioral and social factors. Physicians in practice have an obligation to act on behalf of the general public welfare (for example, by reporting infectious diseases to the proper authorities). Recently, it has become widely accepted that physicians should work to promote smoking cessation, encourage use of seatbelts, and prevent firearm injury. Health hazards should not be ruled out as medical concerns because their remedy requires social or political action. Although the proper form and extent of political involvement for physicians may at times be controversial, concern for the health of the public has been an important responsibility of the medical profession at least since the Industrial Revolution [45].

It may be argued that although physicians have a responsibility to care for persons who are ill even though they are poor and cannot pay, medicine has no particular responsibility with respect to the general condition of poverty. Physicians' efforts to mitigate poverty may be seen as going beyond the bounds of the patient–physician relationship. However, efforts against poverty may have parallels in widely accepted attempts by physicians to prevent child abuse or health hazards in the workplace. Although patients may not ask to be protected from toxins or abuse, physicians have agreed that they have a responsibility to assist patients who may be in danger and, when possible, to prevent harm. If poverty is connected to ill health in a direct and powerful way, it can be argued that physicians have some degree of responsibility for addressing poverty itself to the best of their ability.

Physicians Can Help Mitigate the Health Inequalities Caused by Poverty

A panel convened by the King's Fund of London recently proposed four types of interventions to correct health inequalities related to poverty: addressing social and economic factors; reducing barriers to the adoption of healthier ways of living; improving the physical environment; and improving access to appropriate, effective health and social services [46]. Physicians have clear roles to play in each of these efforts.

Physicians can address social and economic factors both on the level of the individual patient and on the level of the community. By being aware of socioeconomic factors, such as insurance status, educational background, occupational history, housing conditions, and social isolation, physicians can make more comprehensive diagnoses and tailor therapies to patients' needs. Unfortunately, in residency training, the social history (if it is taken at all) is often labeled "noncontributory." Raik and colleagues [47] examined the content of resident case presentations on inpatient rounds and found remarkably low rates of mention of socioeconomic factors. Physicians as teachers can address these factors on rounds and in describing their own patients to trainees and colleagues.

On the community level, physicians can advocate for public policies to improve the health of the disadvantaged. Jarman [48] showed that physicians know that it is more complicated and takes more time to care for poor patients than for patients who are not poor. With this evidence, he was able to persuade the National Health Service in the United Kingdom to take patient economic status into account in rewarding general practitioners who work in deprived areas. Given the growth of managed care in the United States, physicians should be at the forefront of those calling for poverty-based risk adjustments to capitated payments.

As research scientists, physicians can advance the understanding of the mechanisms by which deprivation leads to ill health and the development of more effective interventions to reduce inequality in health [49]. Similarly, physicians who are aware of the adverse effects of international debt on health can urge debt relief for the poorest countries [50].

Physicians may also be able to assist in removing barriers to healthy lifestyles-for example, campaigning against the promotion of tobacco, which is increasingly being targeted to adolescents in less developed countries and in minority communities in the United States [51].

Physicians can affect environmental factors associated with poverty by advocating for legislation to maintain and improve the quality of air, drinking water, and food. Physician-led public health efforts in the United States have been instrumental in reducing the incidence of lead poisoning, which is strongly associated with poverty. Internationally, physicians are participating in local initiatives surrounding Agenda 21, developed at the 1992 Earth Summit in Rio de Janeiro, Brazil. More than 1300 local communities in 31 countries have developed their own action plans, many of which feature health issues. Through the WHO Healthy Cities Project, cities have addressed such issues as smoking, sanitation, air pollution, and socioeconomic differences in health [52].

Approaches to improving access to effective health and social services in the United States and elsewhere have been extensively reviewed [39, 53]. However, more than 800 million persons lack access to health services worldwide, and the increasing imposition of user fees (copayments and deductibles) in many countries has exacerbated inequities in care [54]. Physicians and their associations should lead the movement for universal access to health care [55].

An international meeting on health and poverty hosted by WHO and Action in International Medicine (which has approximately 100 affiliated organizations in more than 30 countries) urged associations of health professionals to engage in activities to reduce health inequalities due to poverty [56]. Dr. Gro Harlem Brundtland, the newly appointed Director General of WHO, has indicated that she intends to make the reduction of ill health due to poverty a priority for her term of office [57]. The United Nations Declaration of Human Rights includes access to the basic necessities of life, such as food and water, as well as health care. However, 50 years after the Declaration was written, we are still far from providing this access to everyone. Physicians have an important role to play in helping to transform the rhetoric of the Declaration into reality.

Dr. Haines: Department of Primary Care and Population Sciences, Royal Free and University College Schools of Medicine, Rouland Hill Street, London, NW3 2PF, United Kingdom.

Dr. Fein: Cornell University Medical College, 1300 York Avenue, Box 577, New York, NY 10021.

Dr. Addington: Primary Care Institute, Rush School of Medicine, 1653 West Congress Parkway, Suite 807 Kidston, Chicago, IL 60612.

Dr. Lawrence: Professional Education and Programs, Johns Hopkins School of Public Health, 615 North Wolfe Street, Room 205, Baltimore, MD 21218.

Dr. Cassel: Department of Geriatrics and Adult Development, Mount Sinai School of Medicine, New York, NY 10029.