World health report

Executive summary

Health of adults

Globally about 51 million people of all ages died in 1993, about three-quarters of them adults. Some 39 million deaths took place in the developing world and about 12 million in the developed. Poor countries had three times more deaths than rich ones.

Communicable diseases such as tuberculosis and respiratory infections as well as maternal, perinatal and neonatal conditions account for about 20 million, or about 40%, of the 51 million global deaths; and 99% of these occur in the developing world.

Noncommunicable diseases such as cancer and heart disease account for about 19 million deaths, or 36% of the global total, divided more or less equally between the developing and the developed world. The great majority of such deaths are among adults.

External causes such as accidents and violence account for about 4 million deaths, or some 8% of the total, again mostly among adults. Developing countries have nearly four times the number of deaths from these causes as the developed world. Other and unknown causes account for the remaining 16% of deaths worldwide.

Maternal complications claim another 508 000 lives a year.

Of the 20 million deaths due to communicable diseases more than 16 million, or about 80%, are due to infectious and parasitic diseases. Tuberculosis kills about 3 million people, malaria around 2 million and hepatitis B possibly 1 million.

Among the major communicable diseases, tuberculosis was responsible for more than 5% of the global total of deaths - over 7 000 a day - and it is estimated that there will be 8.8 million new cases in 1995 - equal to more than 1 000 new cases every hour of every day. Drug treatment, in most cases costing as little as US $13-30 per person for a six-month course, can cure people; but providing the drugs to those who need them, and ensuring that patients take them for the required period, is a major public health challenge.

Meanwhile the lethal relationship of tuberculosis with HIV is making the death toll many times worse. During the next 10 years in Asia alone it is estimated that tuberculosis and AIDS together will kill more people than the entire populations of the cities of Singapore, Beijing, Yokohama and Tokyo combined.

Malaria, directly or in association with acute respiratory infections and anaemia, causes around 2 million deaths a year, the vast majority among young children, and some 400 million cases annually. Globally more than 2 billion people are threatened. The estimated direct and indirect cost of the disease in Africa alone is expected to reach US $1.8 billion by 1995.

Cholera has become endemic in many countries in Africa, Asia and Latin America. In 1993 there were 377 000 new cases reported and only 6 800 deaths. Nevertheless, the number of cases and deaths remain at far higher levels than those reported earlier.

Among the other communicable diseases, dengue and dengue haemorrhagic fever are now the most important and rapidly rising arbovirus infections in the world. There are millions of cases annually, with approximately 500 000 people needing hospital treatment, and thousands of deaths. The ancient scourge of leprosy still causes 600 000 new cases a year. Between 2 and 3 million people are disabled by the disease, including those who have been cured but crippled in some way prior to treatment. Onchocerciasis (river blindness) infects 18 million people in 34 countries, while dracunculiasis (guinea- worm disease) causes terrible suffering and disability among 3 million of the world's most deprived people who have no access to safe water. Chagas disease affects 17 million people in 21 countries in Latin America and causes 45 000 deaths and 400 000 cases of heart and stomach disease annually. African trypanosomiasis (sleeping sickness), kills an estimated 55 000 people a year. Schistosomiasis (bilharziasis or snail fever) affects 200 million people in 74 countries in the Americas, Africa and Asia and kills perhaps 200 000 people. Leishmaniasis infects about 13 million people. Visceral leishmaniasis, also known as kala-azar, is the most severe form. Almost always fatal if untreated, it causes some 500 000 cases and more than 80 000 deaths a year. Lymphatic filariasis (elephantiasis) affects around 100 million people, while Ascaris causes clinical symptoms in as many as 214 million people, Trichuris in 133 million and hookworm in 96 million.

Sexually transmitted diseases impose a huge health burden across the world. Some 236 million people are estimated to have trichomoniasis, with 94 million new cases a year. Chlamydial infections affect some 162 million people, with 97 million new cases annually. An estimated 32 million new cases of genital warts occur each year, and there are some 78 million new cases of gonorrhoea. Genital herpes infects 21 million people a year, and syphilis 19 million. More than 9 million people are infected with chancroid each year.

Many, if not all, STDs could be avoided if condoms were used. Most STDs can be treated effectively and cheaply - the cost of treating genital ulcer disease, for instance being between US $0.5 and US $4 per person. But there are problems in the supply and accessibility of services, compounded by fear of stigma on the part of patients and the attitude of some service providers.

HIV and AIDS continue to spread relentlessly. WHO estimates that in 1994 HIV prevalence among adults worldwide was over 13 million. Some 6 000 people are becoming infected each day. In parts of Africa and Asia the virus is advancing rapidly. In southern and south-eastern Asia HIV infections were estimated at 2.5 million - a million more than in 1993.

In 1993, 2 065 cases of human plague (with 191 deaths) recorded in 10 countries in Africa, Asia and the Americas were notified to WHO. That number exceeded the 1992 total and the annual average for the previous 10 years. The outbreak was a stern reminder to the world that a dreaded disease, often regarded as a scourge of the past, still exists.

Noncommunicable diseases such as those of the circulatory system account for 10 million deaths globally, with more than 5 million due to heart disease and another 4 million due to cerebrovascular conditions (such as stroke). These and other noncommunicable diseases that primarily affect adults are also emerging as a major cause of death in the developing world. Although until recently heart disease and stroke were perceived as problems of the developed countries, about 44% of total deaths from these causes now occur in the developing world. Cancer accounts for 6 million or 12% of deaths globally - with the majority of them, 58%, in the developing world.

Among the other noncommunicable diseases, chronic obstructive pulmonary diseases such as chronic bronchitis and emphysema killed nearly 2.9 million adults in 1993, representing about 6% of total deaths. The number of sufferers in the world from these diseases is put at 600 million. This is the second largest known category of persons with a single disorder recorded by WHO. At the same time there are believed to be 275 million asthma sufferers in the world, although WHO has no data on the number of deaths due to this condition.

Diabetes mellitus is a growing public health problem in both developed and developing countries. A recent WHO expert group estimated that more than 100 million people will suffer from diabetes by the end of this century - 85-90% with the non-insulin dependent form. In Europe the prevalence of diabetes is 2-5% per cent of the adult population. In India a quarter of the population is affected by the age of 60, and 1 in 5 North Americans will acquire the disease by the age of 70. One recent estimate put the cost of diabetes in the USA alone, both direct and indirect, at US $92 billion a year.

Mental ill-health is at the bottom of the medical pecking order. Only the most severe cases, such as schizophrenia or manic depression, receive what minimal care there is, even in developed countries. There are disturbing signs that society would sooner have such patients wandering the streets homeless than provide them with the care they need. The stigma of "madness" is still a potent barrier in preventing ill people from receiving help. Some 500 million people are believed to suffer from neurotic, stress- related and somatoform disorders. A further 200 million are affected by mood disorders such as chronic and manic depression. Mental retardation afflicts some 83 million people, epilepsy 30 million, dementia 22 million and schizophrenia 16 million.

Smoking is emerging as the world's largest single preventable cause of illness and death. WHO estimates that there are about 1.1 billion smokers in the world today. About 800 million are in the developing world - nearly three times as many as in developed countries. Smoking already kills an average of 3 million adults a year worldwide. If current trends continue, this figure is expected to reach 10 million by the year 2020.

In the area of women's health and childbirth, the differences in maternal mortality between countries are shocking. In Europe maternal mortality is 50 per 100 000 live births. In some of the least developed countries the rate exceeded 700 maternal deaths per 100 000 births in 1991. In developing countries 1 in 5 deaths of women of reproductive age are due to complications of pregnancy and delivery. Half a million women die every year from conditions which are easily preventable.