2.13 Risk factors in health See Table 2.13 here

Commentary
About the data
Definitions
Data sources

Back to Contents

Public health programs typically serve needs that cannot be met by private or market-based activities. Their objective is to prevent disease or injury and to provide information on self-cure and the importance of seeking care. By contrast, clinical services respond to demand from individuals who are already sick, and they are often provided, partly or entirely, through private resources. Providing essential clinical services is often the responsibility of public health programs, however.

Governments face difficult choices in the use of public money devoted to health. The World Bank's World Development Report 1993: Investing in Health identified six particularly cost-effective public health activities: providing population-based services, such as immunization and mass screening for widespread diseases; improving diet and nutrition; providing family planning and maternal health care; reducing the abuse of tobacco, alcohol, and other drugs; improving household and external environments, including mitigating occupational hazards; and preventing AIDS (table 2.13a). The report recommended that public health programs in developing countries include components in most or all of these six areas, depending on local epidemiological conditions. The criterion for including a service should be its cost-effectiveness in dealing with major threats to health. The report identified care for sick children, prenatal and delivery care, treatment of sexually transmitted diseases, and short-course therapy for tuberculosis as the most cost-effective essential clinical services.

Government action in many areas of public health has already had important payoffs in developing countries. Immunization saves an estimated 3 million lives a year, and diarrheal disease control more than one million. Contraceptive use has increased in developing countries from about 10 percent of married couples in the mid-1960s to 53 percent in 1990 (WHO 1996b), enabling women to space or avoid pregnancies. But governments need to expand their efforts and move forward with public health initiatives, especially in the areas of child malnutrition, tobacco use, and AIDS. The last two are high-risk factors in developing countries and are expected to be among the main causes of death and disability in the next few decades.

a. Refers to the Expanded Programme of Immunization, which focuses on preventing selected childhood diseases and, through support to national immunization programs, aims to achieve 90 percent immunization coverage of children born each year.

Source: World Bank 1993c.

Table 2.13b Prevalence of child malnutrition, 1985, 1990, and 1995
percentage of children under 5

Note: Data refer to 93 countries and are based on World Bank regional groupings.

Source: WHO estimates.

Back to top
Back to Contents

Either directly or in association with such infectious diseases as measles, diarrhea, or respiratory diseases, malnutrition accounts for about a quarter of deaths among children under age five. According to World Health Organization (WHO) estimates, about a third of the children in developing countries are malnourished (table 2.13b). Because chronic malnutrition is mostly a consequence of poverty, governments need to ensure food distribution, especially during periods of seasonal variability, and control infectious diseases. But equally important is the need to encourage more healthy eating by providing information on improving diets.

Tobacco causes more deaths than all other psychoactive substances combined (World Bank 1993c). About 3 million premature deaths a year (6 percent of the world total in 1990) are attributable to smoking. If current trends continue, annual deaths related to tobacco smoking are projected to reach 10 million by 2020, with most of the increase in developing countries. Effectively discouraging tobacco use involves slow changes, and public education is central to this process. Information on the risks of smoking—and taxes on tobacco—are changing behavior in some countries, although so far mostly in richer ones.

AIDS has killed about 6 million people and infected 28 million (WHO 1996b). More than 80 percent of those infected in 1990 lived in developing countries; by 2000 this share is expected to increase to 95 percent. AIDS is the largest cause of death in many African cities, and it is likely to become a major cause of death in Sub-Saharan Africa and in India and other Asian countries unless action is taken now (Bobadilla and others 1994). A combination of strategies is required to stem the spread of AIDS. Most crucial is providing information on how to avoid infection and promoting condom use, which has proved successful in Uganda and Zaire (World Bank 1993c).

Back to top
Back to Contents

The limited availability of data on health status is a major constraint to assessing the health situation in developing countries. Surveillance data are lacking for a number of major public health concerns. Estimates of prevalence and incidence are available for only a few diseases and a handful of countries, and are notoriously unreliable and variable. National health authorities differ widely in their capability and willingness to collect or report information. Even when intentions are good, reporting is based on definitions that may vary widely across countries or over time. To compensate for the paucity of data and ensure a reasonable degree of reliability and international comparability, the World Health Organization (WHO) prepares estimates in accordance with epidemiological and statistical procedures.

Low birthweight is associated with maternal malnutrition, raises the risk of infant mortality, and leads to poor growth in infancy and childhood, thus increasing the incidence of other forms of retarded development. Estimates of low-birthweight infants are drawn from hospital records and community surveys. But since many births in developing countries take place at home without assistance from formal medical practitioners and are seldom recorded, these data should be treated with caution.

Estimates of child malnutrition, here defined by weight for age, are from survey data. The minimum criterion for including a survey in the global analysis is that it be at least a national survey. Weight for age is a composite indicator of both weight for height (wasting) and height for age (stunting). The disadvantage of this indicator is that it cannot indicate whether the malnutrition is due to stunting or wasting. This indicator is nevertheless useful for comparisons with earlier surveys, as weight for age was the first anthropometric measure in general use. Methods of assessment vary, but the indicator used here is less than minus 2 standard deviations from the median weight for age of the U.S. National Center of Health Statistics reference population aged 0-59 months. The reference population, adopted by the WHO in 1983, is based on children from the United States who are assumed to be well nourished. Where this indicator could not be estimated (because a different age range or assessment method was used), priority was given to deriving identically defined prevalence comparable within the country across time. This approach has minor effects on the estimated rates, which are considered generally comparable across countries by the WHO.

Adult HIV-1 seroprevalence rates reflect the rate of HIV-1 infection estimated by WHO for each country's adult population. The global HIV pandemic currently involves two HIV viruses: HIV-1 and HIV-2. HIV-1 is the dominant type worldwide. HIV-2 is found principally in West Africa, but cases have been reported in East Africa, Europe, Asia, and Latin America. There are at least 10 different genetic subtypes of HIV-1, but their biological and epidemiological significance is unclear at present. While the routes of transmission for the two viruses are the same, HIV-2 appears to be less easily transmitted than HIV-1 and the progression from HIV-2 infection to AIDS appears to be slower than that for HIV-1. AIDS is late-stage infection characterized by a severely weakened immune system that can no longer ward off life-threatening opportunistic infections and cancers. Surveys of HIV seroprevalence are not based on national samples. Most HIV data originate from diagnostic centers or screening programs and are therefore subject to selection (usually high-risk groups) and participation bias. The extent of bias in the estimates is determined by how different the sampled population group or geographical area is from the general population.

Tobacco consumption, where raw-leaf equivalents are not available, is derived from Food and Agriculture Organization (FAO) data by converting data on consumption or sale of products. In some cases consumption is calculated from production of and net trade in leaf and products. Estimates for 1995 are based on assumptions on the growth of private consumption expenditure to derive per capita demand for tobacco. The demand function and elasticities were based on an analysis of recent national family budget surveys and previous time-series data on consumption. Antismoking campaigns and other preventive activities that have influenced tobacco consumption were also considered for some countries through a trend factor, independent of income and price.

Back to top
Back to Contents

• Low-birthweight babies are children born weighing less than 2,500 grams, with the measurement taken within the first hours of life, before significant postnatal weight loss has occurred.

• Prevalence of child malnutrition is the percentage of children under 5 whose weight for age is less than minus 2 standard deviations from the median of the reference population.

• Adult HIV-1 seroprevalence reflects the estimated rate of infection in each country's adult population (age 15 and older).

• Tobacco consumption is kilograms of dry-weight tobacco consumed per adult (aged 15 and older) per year.

Data presented here are drawn from a variety of sources. In order of their appearance in the table, these are:

WHO, World Health Statistics Annual. United Nations, Update on the Nutrition Situation. WHO. FAO, Tobacco: Supply, Demand and Trade Projections 1995 and 2000.

Back to top
Back to Contents