Showing papers in "Bulletin of The World Health Organization in 2005"

The environment and disease: association or causation?

Abstract: In 1965, Sir Austin Bradford Hill offered his thoughts on: “What aspects of [an] association should we especially consider before deciding that the most likely interpretation of it is causation?” He proposed nine means for reasoning about the association, which he named as: strength, consistency, specificity, temporality, biological gradient, plausibility, coherence, experiment, and analogy. In this paper, we look at what motivated Bradford Hill to propose we focus on these nine features. We contrast Bradford Hill’s approach with a currently fashionable framework for reasoning about statistical associations – the Common Task Framework. And then suggest why following Bradford Hill, 50+ years on, is still extraordinarily reasonable.

The burden of oral disease: challenges to improving oral health in the 21st century.

Abstract: Dental caries and periodontal diseases have historically been considered the most important part of the global burden of oral diseases. At present, the distribution and severity of oral diseases vary in different parts of the world and within the same country or region. Dental caries is still a major public health problem in most industrialized countries, affecting 60-90% of schoolchildren and the vast majority of adults. It is also a prevalent oral disease in several Asian and Latin American countries, while it appears to be less common and less severe in most African countries. It is expected, however, that the incidence of dental caries will increase in the near future in many developing countries of Africa, as a result of growing consumption of sugars and inadequate exposure to fluorides. The significant role of socio-behavioural and environmental factors in oral disease and health is demonstrated in a large number of epidemiological surveys. The current pattern of dental caries reflects primarily distinct risk profiles across countries (related to living conditions, lifestyles and environmental factors) and the implementation of preventive oral health systems. In some industrialized countries there has been a positive trend in the reduction of tooth loss among adults in recent years, though the proportion of edentulous persons in the elderly population is still high in some countries. In most developing countries, access to oral health services is limited and teeth are often left untreated or are extracted because of pain or discomfort. Tooth loss and impaired oral function are therefore expected to increase as a public health problem in many developing countries. Tooth loss in adult life may also be attributable to poor periodontal health. Severe periodontitis, which may result in tooth loss, is found in 5-15% of most populations. In industrialized countries, studies show that tobacco use is a major risk factor for adult periodontal disease. With the growing consumption of tobacco in many developing countries, the risk of periodontal disease and tooth loss may therefore increase. Oral cancer is closely related to the use of tobacco and excessive consumption of alcohol. The prevalence of oral cancer is particularly high among men, and is the eighth most common cancer worldwide. In south and central Asia, consumption of tobacco in various forms is particularly high, and cancer of the oral cavity ranks among the three most common types of cancer. Periodontal disease and tooth loss are also related to chronic diseases such as diabetes mellitus: the growing incidence of diabetes may further impact negatively on oral health of people in several developing countries. …

The global burden of oral diseases and risks to oral health

Abstract: 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.

Counting the dead and what they died from: an assessment of the global status of cause of death data

Abstract: OBJECTIVE: We sought to assess the current status of global data on death registration and to examine several indicators of data completeness and quality. METHODS: We summarized the availability of death registration data by year and country. Indicators of data quality were assessed for each country and included the timeliness, completeness and coverage of registration and the proportion of deaths assigned to ill-defined causes. FINDINGS: At the end of 2003 data on death registration were available from 115 countries, although they were essentially complete for only 64 countries. Coverage of death registration varies from close to 100% in the WHO European Region to less than 10% in the African Region. Only 23 countries have data that are more than 90% complete, where ill-defined causes account for less than 10% of total of causes of death, and where ICD-9 or ICD-10 codes are used. There are 28 countries where less than 70% of the data are complete or where ill-defined codes are assigned to more than 20% of deaths. Twelve high-income countries in western Europe are included among the 55 countries with intermediate-quality data. CONCLUSION: Few countries have good-quality data on mortality that can be used to adequately support policy development and implementation. There is an urgent need for countries to implement death registration systems, even if only through sample registration, or enhance their existing systems in order to rapidly improve knowledge about the most basic of health statistics: who dies from what?

Re-evaluating the burden of rabies in Africa and Asia

Abstract: Objective To quantify the public health and economic burden of endemic canine rabies in Africa and Asia. Methods Data from these regions were applied to a set of linked epidemiological and economic models. The human population at risk from endemic canine rabies was predicted using data on dog density, and human rabies deaths were estimated using a series of probability steps to determine the likelihood of clinical rabies developing in a person after being bitten by a dog suspected of having rabies. Model outputs on mortality and morbidity associated with rabies were used to calculate an improved disability-adjusted life year (DALY) score for the disease. The total societal cost incurred by the disease is presented. Findings Human mortality from endemic canine rabies was estimated to be 55 000 deaths per year (90% confidence interval (CI) = 24 000–93 000). Deaths due to rabies are responsible for 1.74 million DALYs lost each year (90% CI = 0.75–2.93). An additional 0.04 million DALYs are lost through morbidity and mortality following side-effects of nerve-tissue vaccines. The estimated annual cost of rabies is US$ 583.5 million (90% CI = US$ 540.1–626.3 million). Patient-borne costs for post-exposure treatment form the bulk of expenditure, accounting for nearly half the total costs of rabies. Conclusions Rabies remains an important yet neglected disease in Africa and Asia. Disparities in the affordability and accessibility of post-exposure treatment and risks of exposure to rabid dogs result in a skewed distribution of the disease burden across society, with the major impact falling on those living in poor rural communities, in particular children.

The global burden of disease attributable to low consumption of fruit and vegetables: implications for the global strategy on diet

Abstract: OBJECTIVE: We estimated the global burden of disease attributable to low consumption of fruit and vegetables, an increasingly recognized risk factor for cardiovascular disease and cancer, and compared its impact with that of other major risk factors for disease. METHODS: The burden of disease attributable to suboptimal intake of fruit and vegetables was estimated using information on fruit and vegetable consumption in the population, and on its association with six health outcomes (ischaemic heart disease, stroke, stomach, oesophageal, colorectal and lung cancer). Data from both sources were stratified by sex, age and by 14 geographical regions. FINDINGS: The total worldwide mortality currently attributable to inadequate consumption of fruit and vegetables is estimated to be up to 2.635 million deaths per year. Increasing individual fruit and vegetable consumption to up to 600 g per day (the baseline of choice) could reduce the total worldwide burden of disease by 1.8%, and reduce the burden of ischaemic heart disease and ischaemic stroke by 31% and 19% respectively. For stomach, oesophageal, lung and colorectal cancer, the potential reductions were 19%, 20%, 12% and 2%, respectively. CONCLUSION: This study shows the potentially large impact that increasing fruit and vegetable intake could have in reducing many noncommunicable diseases. It highlights the need for much greater emphasis on dietary risk factors in public health policy in order to tackle the rise in noncommunicable diseases worldwide, and suggests that the proposed intersectoral WHO/FAO fruit and vegetable promotion initiative is a crucial component in any global diet strategy.

Standardized interpretation of paediatric chest radiographs for the diagnosis of pneumonia in epidemiological studies

Abstract: BACKGROUND: Although radiological pneumonia is used as an outcome measure in epidemiological studies, there is considerable variability in the interpretation of chest radiographs. A standardized method for identifying radiological pneumonia would facilitate comparison of the results of vaccine trials and epidemiological studies of pneumonia. METHODS: A WHO working group developed definitions for radiological pneumonia. Inter-observer variability in categorizing a set of 222 chest radiographic images was measured by comparing the readings made by 20 radiologists and clinicians with a reference reading. Intra-observer variability was measured by comparing the initial readings of a randomly chosen subset of 100 radiographs with repeat readings made 8-30 days later. FINDINGS: Of the 222 images, 208 were considered interpretable. The reference reading categorized 43% of these images as showing alveolar consolidation or pleural effusion (primary end-point pneumonia); the proportion thus categorized by each of the 20 readers ranged from 8% to 61%. Using the reference reading as the gold standard, 14 of the 20 readers had sensitivity and specificity of > 0.70 in identifying primary end-point pneumonia; 13 out of 20 readers had a kappa index of > 0.6 compared with the reference reading. For the 92 radiographs deemed to be interpretable among the 100 images used for intra-observer variability, 19 out of 20 readers had a kappa index of > 0.6. CONCLUSION: Using standardized definitions and training, it is possible to achieve agreement in identifying radiological pneumonia, thus facilitating the comparison of results of epidemiological studies that use radiological pneumonia as an outcome.

Oral health, general health and quality of life.

Abstract: The compartmentalization involved in viewing the mouth separately from the rest of the body must cease because oral health affects general health by causing considerable pain and suffering and by changing what people eat, their speech and their quality of life and well-being. Oral health also has an effect on other chronic diseases (1). Because of the failure to tackle social and material de-terminants and incorporate oral health into general health promotion, millions suffer intractable toothache and poor quality of life and end up with few teeth.Health policies should be reori-ented to incorporate oral health using sociodental approaches to assessing needs and the common risk factor approach for health promotion (1, 2). Oral diseases are the most common of the chronic diseases and are important public health problems because of their prevalence, their impact on individuals and society, and the expense of their treatment. The determinants of oral diseases are known — they are the risk factors common to a number of chronic diseases: diet and dirt (hygiene), smok-ing, alcohol, risky behaviours causing injuries, and stress — and effective public health methods are available to prevent oral diseases.In some countries, oral diseases are the fourth most expensive diseases to treat. Treating caries, estimated at US$ 3513 per 1000 children, would exceed the total health budget for children of most low-income countries (3). The situation for adults in developing coun-tries is worse, as they suffer from the accumulation of untreated oral diseases. There are few efficient dental care sys-tems to cope with their problems, and where there are, the cost is beyond most people’s means. Millions with untreated caries have cavities and suppuration, yet planners continue to overlook oral dis-eases, despite their significant impact on cost and quality of life. This oversight will lead to more decay and expensive, ineffective clinical interventions.

Health information systems: the foundations of public health

Abstract: Public health decision-making is critically dependent on the timely availability of sound data. The role of health information systems is to generate, analyse and disseminate such data. In practice, health information systems rarely function systematically. The products of historical, social and economic forces, they are complex, fragmented and unresponsive to needs. International donors in health are largely responsible for the problem, having prioritized urgent needs for data over longer-term country capacity-building. The result is painfully apparent in the inability of most countries to generate the data needed to monitor progress towards the Millennium Development Goals. Solutions to the problem must be comprehensive; money alone is likely to be insufficient unless accompanied by sustained support to country systems development coupled with greater donor accountability and allocation of responsibilities. The Health Metrics Network, a global collaboration in the making, is intended to help bring such solutions to the countries most in need.

No cry at birth: global estimates of intrapartum stillbirths and intrapartum-related neonatal deaths.

Abstract: Objective Fewer than 3% of 4 million annual neonatal deaths occur in countries with reliable vital registration (VR) data. Global estimates for asphyxia-related neonatal deaths vary from 0.7 to 1.2 million. Estimates for intrapartum stillbirths are not available. We aimed to estimate the numbers of intrapartum-related neonatal deaths and intrapartum stillbirths in the year 2000. Methods Sources of data on neonatal death included: vital registration (VR) data on neonatal death from countries with full (> 90%) VR coverage (48 countries, n = 97 297); studies identified through literature searches (> 4000 abstracts) and meeting inclusion criteria (46 populations, 30 countries, n = 12 355). A regression model was fitted to cause-specific proportionate mortality data from VR and the literature. Predicted cause-specific proportions were applied to the number of neonatal deaths by country, and summed to a global total. Intrapartum stillbirths were estimated using median cause-specific mortality rate by country (73 populations, 52 countries, n = 46 779) or the subregional median in the absence of country data. Findings Intrapartum-related neonatal deaths were estimated at 0.904 million (uncertainty 0.65–1.17), equivalent to 23% of the global total of 4 million neonatal deaths. Country-level model predictions compared well with population-based data sets not included in the input data. An estimated 1.02 million intrapartum stillbirths (0.66–1.48 million) occur annually, comprising 26% of global stillbirths. Conclusion Intrapartum-related neonatal deaths account for almost 10% of deaths in children aged under 5 years. Intrapartum stillbirths are a huge and invisible problem, but are potentially preventable. Programmatic attention and improved information are required.

Strategies and approaches in oral disease prevention and health promotion

Abstract: Oral health is an important element of general health and well-being. Although largely preventable, many people across the world still suffer unnecessarily from the pain and discomfort associated with oral diseases. In addition, the costs of dental treatment are high, both to the individual and to society. Effective evidence-based preventive approaches are needed to address this major public health problem. The aim of this paper is to outline public health strategies to promote oral health and reduce inequalities. An extensive collection of public health policy documents produced by WHO are reviewed to guide the development of oral health strategies. In addition a range of Cochrane and other systematic reviews assessing the evidence base for oral health interventions are summarized. Public health strategies should tackle the underlying social determinants of oral health through the adoption of a common risk approach. Isolated interventions which merely focus on changing oral health behaviours will not achieve sustainable improvements in oral health. Radical public health action on the conditions which determine unhealthy behaviours across the population is needed rather than relying solely on the high-risk approach. Based upon the Ottawa Charter, a range of complementary strategies can be implemented in partnership with relevant local, national and international agencies. At the core of this public health approach is the need to empower local communities to become actively involved in efforts to promote their oral health.

Health-promoting schools: an opportunity for oral health promotion

Abstract: Schools provide an important setting for promoting health, as they reach over 1 billion children worldwide and, through them, the school staff, families and the community as a whole. Health promotion messages can be reinforced throughout the most influential stages of children's lives, enabling them to develop lifelong sustainable attitudes and skills. Poor oral health can have a detrimental effect on children's quality of life, their performance at school and their success in later life. This paper examines the global need for promoting oral health through schools. The WHO Global School Health Initiative and the potential for setting up oral health programmes in schools using the health-promoting school framework are discussed. The challenges faced in promoting oral health in schools in both developed and developing countries are highlighted. The importance of using a validated framework and appropriate methodologies for the evaluation of school oral health projects is emphasized.

Poverty, child undernutrition and morbidity: new evidence from India

Abstract: Undernutrition continues to be a primary cause of ill-health and premature mortality among children in developing countries. This paper examines how the prevalence of undernutrition in children is measured and argues that the standard indices of stunting, wasting and underweight may each be underestimating the scale of the problem. This has important implications for policy-makers, planners and organizations seeking to meet international development targets. Using anthropometric data on 24 396 children in India, we constructed an alternative composite index of anthropometric failure (CIAF) and compared it with conventional indices. The CIAF examines the relationship between distinct subgroups of anthropometric failure, poverty and morbidity, showing that children with multiple anthropometric failures are at a greater risk of morbidity and are more likely to come from poorer households. While recognizing that stunting, wasting and underweight reflect distinct biological processes of clear importance, the CIAF is the only measure that provides a single, aggregated figure of the number of undernourished children in a population.

The public health implications of asthma

Abstract: Asthma is a very common chronic disease that occurs in all age groups and is the focus of various clinical and public health interventions. Both morbidity and mortality from asthma are significant. The number of disability-adjusted life years (DALYs) lost due to asthma worldwide is similar to that for diabetes, liver cirrhosis and schizophrenia. Asthma management plans have, however, reduced mortality and severity in countries where they have been applied. Several barriers reduce the availability, affordability, dissemination and efficacy of optimal asthma management plans in both developed and developing countries. The workplace environment contributes significantly to the general burden of asthma. Patients with occupational asthma have higher rates of hospitalization and mortality than healthy workers. The surveillance of asthma as part of a global WHO programme is essential. The economic cost of asthma is considerable both in terms of direct medical costs (such as hospital admissions and the cost of pharmaceuticals) and indirect medical costs (such as time lost from work and premature death). Direct costs are significant in most countries. In order to reduce costs and improve quality of care, employers and health plans are exploring more precisely targeted ways of controlling rapidly rising health costs. Poor control of asthma symptoms is a major issue that can result in adverse clinical and economic outcomes. A model of asthma costs is needed to aid attempts to reduce them while permitting optimal management of the disease. This paper presents a discussion of the burden of asthma and its socioeconomic implications and proposes a model to predict the costs incurred by the disease.

Infant feeding patterns and risks of death and hospitalization in the first half of infancy: multicentre cohort study

Abstract: OBJECTIVE: To determine the association of different feeding patterns for infants (exclusive breastfeeding, predominant breastfeeding, partial breastfeeding and no breastfeeding) with mortality and hospital admissions during the first half of infancy. METHODS: This paper is based on a secondary analysis of data from a multicentre randomized controlled trial on immunization-linked vitamin A supplementation. Altogether, 9424 infants and their mothers (2919 in Ghana, 4000 in India and 2505 in Peru) were enrolled when infants were 18-42 days old in two urban slums in New Delhi, India, a periurban shanty town in Lima, Peru, and 37 villages in the Kintampo district of Ghana. Mother-infant pairs were visited at home every 4 weeks from the time the infant received the first dose of oral polio vaccine and diphtheria-pertussis-tetanus at the age of 6 weeks in Ghana and India and at the age of 10 weeks in Peru. At each visit, mothers were queried about what they had offered their infant to eat or drink during the past week. Information was also collected on hospital admissions and deaths occurring between the ages of 6 weeks and 6 months. The main outcome measures were all-cause mortality, diarrhoea-specific mortality, mortality caused by acute lower respiratory infections, and hospital admissions. FINDINGS: There was no significant difference in the risk of death between children who were exclusively breastfed and those who were predominantly breastfed (adjusted hazard ratio (HR) = 1.46; 95% confidence interval (CI) = 0.75-2.86). Non-breastfed infants had a higher risk of dying when compared with those who had been predominantly breastfed (HR = 10.5; 95% CI = 5.0-22.0; P < 0.001) as did partially breastfed infants (HR = 2.46; 95% CI = 1.44-4.18; P = 0.001). CONCLUSION: There are two major implications of these findings. First, the extremely high risks of infant mortality associated with not being breastfed need to be taken into account when informing HIV-infected mothers about options for feeding their infants. Second, our finding that the risks of death are similar for infants who are predominantly breastfed and those who are exclusively breastfed suggests that in settings where rates of predominant breastfeeding are already high, promotion efforts should focus on sustaining these high rates rather than on attempting to achieve a shift from predominant breastfeeding to exclusive breastfeeding.

A new definition of drowning: towards documentation and prevention of a global public health problem

Abstract: Drowning is a major global public health problem. Effective prevention of drowning requires programmes and policies that address known risk factors throughout the world. Surveillance, however, has been hampered by the lack of a uniform and internationally accepted definition that permits all relevant cases to be counted. To develop a new definition, an international consensus procedure was conducted. Experts in clinical medicine, injury epidemiology, prevention and rescue from all over the world participated in a series of "electronic" discussions and face-to-face workshops. The suitability of previous definitions and the major requirements of a new definition were intensely debated. The consensus was that the new definition should include both cases of fatal and nonfatal drowning. After considerable dialogue and debate, the following definition was adopted: "Drowning is the process of experiencing respiratory impairment from submersion/immersion in liquid." Drowning outcomes should be classified as: death, morbidity, and no morbidity. There was also consensus that the terms wet, dry, active, passive, silent, and secondary drowning should no longer be used. Thus a simple, comprehensive, and internationally accepted definition of drowning has been developed. Its use should support future activities in drowning surveillance worldwide, and lead to more reliable and comprehensive epidemiological information on this global, and frequently preventable, public health problem.

Emergency medical systems in low- and middle-income countries: recommendations for action

Abstract: Emergency medical care is not a luxury for rich countries or rich individuals in poor countries. This paper makes the point that emergency care can make an important contribution to reducing avoidable death and disability in low- and middle-income countries. But emergency care needs to be planned well and supported at all levels--at the national, provincial and community levels--and take into account the entire spectrum of care, from the occurrence of an acute medical event in the community to the provision of appropriate care at the hospital. The mix of personnel, materials, and health-system infrastructure can be tailored to optimize the provision of emergency care in settings with different levels of resource availability. The misconception that emergency care cannot be cost effective in low-income settings is demonstrably inaccurate. Emergencies occur everywhere, and each day they consume resources regardless of whether there are systems capable of achieving good outcomes. With better planning, the ongoing costs of emergency care can result in better outcomes and better cost-effectiveness. Every country and community can and should provide emergency care regardless of their place in the ratings of developmental indices. We make the case for universal access to emergency care and lay out a research agenda to fill the gaps in knowledge in emergency care.

Current global iodine status and progress over the last decade towards the elimination of iodine deficiency

Abstract: Objective To estimate worldwide iodine nutrition and monitor country progress towards sustained elimination of iodine deficiency disorders. Methods Cross-sectional data on urinary iodine (UI) and total goitre prevalence (TGP) in school-age children from 1993–2003 compiled in the WHO Global Database on Iodine Deficiency were analysed. The median UI was used to classify countries according to the public health significance of their iodine nutrition status. Estimates of the global and regional populations with insufficient iodine intake were based on the proportion of each country’s population with UI below 100 µg/l. TGP was computed for trend analysis over 10 years. Findings UI data were available for 92.1% of the world’s school-age children. Iodine deficiency is still a public health problem in 54 countries. A total of 36.5% (285 million) school-age children were estimated to have an insufficient iodine intake, ranging from 10.1% in the WHO Region of the Americas to 59.9% in the European Region. Extrapolating this prevalence to the general population generated an estimate of nearly two billion individuals with insufficient iodine intake. Iodine intake was more than adequate, or excessive, in 29 countries. Global TGP in the general population was 15.8%. Conclusion Forty-three countries have reached optimal iodine nutrition. Strengthened UI monitoring is required to ensure that salt iodization is having the desired impact, to identify at-risk populations and to ensure sustainable prevention and control of iodine deficiency. Efforts to eliminate iodine deficiency should be maintained and expanded.

WHO study on Prevention of REcurrences of Myocardial Infarction and StrokE (WHO-PREMISE)

Abstract: OBJECTIVE: To determine the extent of secondary prevention of coronary heart disease (CHD) and cerebrovascular disease (CVD) in low- and middle-income countries. METHODS: A descriptive cross-sectional survey of a sample of 10 000 CHD (85.2%) and CVD (14.8%) patients (6252 men; 3748 women) was conducted over 6 months in geographically defined areas. The mean age was 59.2 years (standard deviation (SD), 10.8). Consecutive patients were recruited from a stratified random sample of primary, secondary and tertiary care facilities in defined areas in 10 countries (Brazil, Egypt, India, Indonesia, Islamic Republic of Iran, Pakistan, Russian Federation, Sri Lanka, Tunisia and Turkey). The main outcome measures were levels of lifestyle and physiological risk factors, and the use of drugs for secondary prevention of CHD and CVD. FINDINGS: Approximately 82%, 89% and 77% of patients were aware of the cardiovascular benefits of quitting smoking, a heart-healthy diet and regular physical activity, respectively. About half (52.5%) engaged in less than 30 minutes of physical activity per day, 35% did not follow a heart-healthy diet and 12.5 % were current tobacco users. Blood pressure had been measured in 93.8% (range 71-100%), blood cholesterol in 85.5% (range 29-97%) and blood sugar in 75.5% (range 65-99%) in the preceding 12 months. The proportions who had received medications among CHD and CVD patients were: aspirin, 81.2%, 70.6%; beta-blockers, 48.1%, 22.8%; angiotensin-converting enzyme inhibitor, 39.8%, 37.8%; statins, 29.8%, 14.1%, respectively. About one-fifth of patients with CHD had undergone revascularization. CONCLUSION: A significant proportion of patients did not receive appropriate medications. About 47% of patients had at least two or more modifiable risk factors (smoking, physical inactivity, hypertension, diabetes or hypercholesterolaemia). There are considerable missed opportunities for prevention of recurrences in those with established CVD in low- and middle-income countries.

Mental and social health during and after acute emergencies: emerging consensus?

Abstract: Mental health care programmes during and after acute emergencies in resource-poor countries have been considered controversial. There is no agreement on the public health value of the post-traumatic stress disorder concept and no agreement on the appropriateness of vertical (separate) trauma-focused services. A range of social and mental health intervention strategies and principles seem, however, to have the broad support of expert opinion. Despite continuing debate, there is emerging agreement on what entails good public health practice in respect of mental health. In terms of early interventions, this agreement is exemplified by the recent inclusion of a "mental and social aspects of health" standard in the Sphere handbook's revision on minimal standards in disaster response. This affirmation of emerging agreement is important and should give clear messages to health planners.

The role of diet and nutrition in the etiology and prevention of oral diseases

Abstract: Diet plays an important role in preventing oral diseases including dental caries, dental erosion, developmental defects, oral mucosal diseases and, to a lesser extent, periodontal disease. This paper is intended to provide an overview of the evidence for an association between diet, nutrition and oral diseases and to clarify areas of uncertainty. Undernutrition increases the severity of oral mucosal and periodontal diseases and is a contributing factor to life-threatening noma. Undernutrition is associated with developmental defects of the enamel which increase susceptibility to dental caries. Dental erosion is perceived to be increasing. Evidence suggests that soft drinks, a major source of acids in the diet in developed countries, are a significant causative factor. Convincing evidence from experimental, animal, human observational and human intervention studies shows that sugars are the main dietary factor associated with dental caries. Despite the indisputable role of fluoride in the prevention of caries, it has not eliminated dental caries and many communities are not exposed to optimal quantities of fluoride. Controlling the intake of sugars therefore remains important for caries prevention. Research has consistently shown that when the intake of free sugars is < 15 kg/person/year, the level of dental caries is low. Despite experimental and animal studies suggesting that some starch-containing foods and fruits are cariogenic, this is not supported by epidemiological data, which show that high intakes of starchy staple foods, fruits and vegetables are associated with low levels of dental caries. Following global recommendations that encourage a diet high in starchy staple foods, fruit and vegetables and low in free sugars and fat will protect both oral and general health.

Mycobacterium ulcerans disease

Abstract: Mycobacterium ulcerans disease (Buruli ulcer) is an important health problem in several west African countries. It is prevalent in scattered foci around the world, predominantly in riverine areas with a humid, hot climate. We review the epidemiology, bacteriology, transmission, immunology, pathology, diagnosis and treatment of infections. M. ulcerans is an ubiquitous micro-organism and is harboured by fish, snails, and water insects. The mode of transmission is unknown. Lesions are most common on exposed parts of the body, particularly on the limbs. Spontaneous healing may occur. Many patients in endemic areas present late with advanced, severe lesions. BCG vaccination yields a limited, relatively short-lived, immune protection. Recommended treatment consists of surgical debridement, followed by skin grafting if necessary. Many patients have functional limitations after healing. Better understanding of disease transmission and pathogenesis is needed for improved control and prevention of Buruli ulcer.

Tobacco smoking as a possible etiologic factor in bronchiogenic carcinoma.

Abstract: General Increase.--There is rather general agreement that the incidence of bronchiogenic carcinoma has greatly increased in the last half-century. Statistical studies at the Charity Hospital of New Orleans (Ochsner and DeBakey), (1) the St. Louis City Hospital (Wheeler) (2) and the Veterans Administration Hospital of Hines, Ill. (Avery) (3) have revealed that at these hospitals cancer of the lung is now the most frequent visceral cancer in men. Autopsy statistics throughout the world show a great increase in the incidence of bronchiogenic carcinoma in relation to cancer in general. Kenneway and Kenneway, (4) in a careful statistical study of death certificates in England and Wales from 1928 to 1945, have presented undoubted evidence of a great increase in deaths from cancer of the lung. In this country statistics compiled by the American Cancer Society show a similar trend during the past two decades? Tobacco as a Possible Cause of Increase.--The suggestion that smoking, and in particular cigaret smoking, may be important in the production of bronchiogenic carcinoma has been made by many writers on the subject-even though well controlled and large scale clinical studies are lacking. Adler (6) in 1912 was one of the first to think that tobacco might play some role in this regard. Tylecote, (7) Hoffman, (8) McNally, (9) Lickint, (10) Arkin and Wagner, (11) Roffo (12) and Maier (13) were just a few of the workers who thought that there was some evidence that tobacco was an important factor in the increase of cancer of the lungs. Muller (14) in 1939, from a careful but limited clinical statistical study, offered good evidence that heavy smoking is an important etiologic factor. In 1941 Ochsner and DeBakey (15) called attention to the similarity of the curve of increased sales of cigarets in this country to the greater prevalence of primary cancer of the lung. They emphasized the possible etiologic relationship of cigaret smoking to this condition. In a recent paper Schrek (16) concluded that there is strong circumstantial evidence that cigaret smoking is an etiologic factor in cancer of the respiratory tract and finds that his data are in agreement with the results of a preliminary report presented by Wynder and Graham at the National Cancer Conference in February 1949. (17) Purpose of Study.--The purpose of the present study was to attempt to determine, so far as possible by clinical investigations, statistical methods and experimental studies, the importance of various exogenous factors that might play a role in the induction of bronchiogenic carcinoma. In this regard we intended to learn the relative importance of previous diseases of the lungs, rural and urban distribution of patients, various occupations and hereditary background as well as smoking habits. By obtaining all this information, we hoped to determine whether any of these factors, either singly or in combination, have had an effect in increasing the incidence of bronchiogenic carcinoma. In the present paper the chief emphasis will be placed on our findings in regard to smoking. METHOD OF STUDY The results of this study are based on 684 cases of proved bronchiogenic carcinoma. It should be emphasized that the results in this report have not been obtained from hospital records since we learned at the outset of our study that the routine records did not supply satisfactory answers to our questions. It was therefore decided to seek the desired information by special interviews. Six hundred and thirty-four patients reported on in this paper have been personally interviewed, and in 33 cases we obtained the information by mailing a questionnaire. (18) In the remaining 17 cases information for the questionnaire was obtained from a person who had been intimately acquainted with the patient throughout his adult life. Through the cooperation of many hospitals and physicians throughout all parts of the country who permitted us to interview their patients, it is felt that a fairly good cross section of the entire United States has been obtained. …

World Report on Knowledge for Better Health: strengthening health systems

Abstract: It is a painful irony that in parts of some developing countries, it is not uncommon for people to fall sick and die of diseases that can be easily prevented and treated. A simple solution of sugar, salt and water could save the lives of thousands of children who die of diarrhoeal diseases every year. Malaria kills hundreds of thousands of children who could have been protected by sleeping under insecticide-treated bednets or cured by the use of effective drugs. Lacking access to antiretroviral drugs, thousands of HIV-infected persons die prematurely. These and other examples illustrate the gap between existing knowledge and health technologies and their application. The authors of the World Report on Knowledge for Better Health have tackled the important question of how to close the gap between knowledge and its application in the health sector. The book's five chapters (Learning to improve health, Towards a scientific basis for health systems, Strengthening health research systems, Linking research to action, Recommendations and action plan) present a well-argued and carefully illustrated case for the systematic use of knowledge derived from research. It draws on previous studies and reports that have addressed aspects of the problem and provides a useful synthesis of current thinking. The 1990 report of the Commission on Health Research for Development provided many of the seminal ideas and concepts on global health research. Follow-up initiatives by the Council on Health Research for Development (COHRED) and by the Global Forum for Health Research (GFHR) have extended the Commission's work. It would have been useful if the Report had highlighted the lessons that could be learned from these and other initiatives. For example, a critical review of COHRED's experience in strengthening national health research would have revealed to readers how the authors used those lessons to inform their proposed recommendations and action plan. The Report recommends a strengthening of national health research systems, with particular emphasis on strategic research, to facilitate the translation of advances in knowledge into effective intervention programmes. The authors point out that many developing countries do not provide appropriate financial support for health research. Not only does this severely limit the effectiveness of national scientists in these countries , but also more seriously, reflects a persistent failure among health officials to recognize how health research could facilitate better analysis of problems and more effective interventions. The complementary recommendations on strengthening health systems aim at ensuring …

Leprosy: too complex a disease for a simple elimination paradigm

Abstract: Can leprosy be eliminated? This paper considers the question against the background of the WHO programme to eliminate leprosy. In 1991 the World Health Assembly set a target of eliminating leprosy as a public health problem by 2000. Elimination was defined as reaching a prevalence of < 1 case per 10 000 people. The elimination programme has been successful in delivering highly effective antibiotic therapy worldwide. However, despite this advance, new-case detection rates remain stable in countries with the highest rates of endemic leprosy, such as Brazil and India. This suggests that infection has not been adequately controlled by antibiotics alone. Leprosy is perhaps more appropriately classed as a chronic stable disease than as an acute infectious disease responsive to elimination strategies. In many countries activities to control and treat leprosy are being integrated into the general health-care system. This reduces the stigma associated with leprosy. However, leprosy causes long-term immunological complications, disability and deformity. The health-care activities of treating and preventing disabilities need to be provided in an integrated setting. Detecting new cases and monitoring disability caused by leprosy will be a challenge. One solution is to implement long-term surveillance in selected countries with the highest rates of endemic disease so that an accurate estimate of the burden of leprosy can be determined. It is also critical that broad-based research into this challenging disease continues until the problems are truly solved.

Oral lesions in infection with human immunodeficiency virus

Abstract: This paper discusses the importance of oral lesions as indicators of infection with human immunodeficiency virus (HIV) and as predictors of progression of HIV disease to acquired immunodeficiency syndrome (AIDS). Oral manifestations are among the earliest and most important indicators of infection with HIV. Seven cardinal lesions, oral candidiasis, hairy leukoplakia, Kaposi sarcoma, linear gingival erythema, necrotizing ulcerative gingivitis, necrotizing ulcerative periodontitis and non-Hodgkin lymphoma, which are strongly associated with HIV infection, have been identified and internationally calibrated, and are seen in both developed and developing countries. They may provide a strong indication of HIV infection and be present in the majority of HIV-infected people. Antiretroviral therapy may affect the prevalence of HIV-related lesions. The presence of oral lesions can have a significant impact on health-related quality of life. Oral health is strongly associated with physical and mental health and there are significant increases in oral health needs in people with HIV infection, especially in children, and in adults particularly in relation to periodontal diseases. International collaboration is needed to ensure that oral aspects of HIV disease are taken into account in medical programmes and to integrate oral health care with the general care of the patient. It is important that all health care workers receive education and training on the relevance of oral health needs and the use of oral lesions as surrogate markers in HIV infection.

Monitoring low birth weight: an evaluation of international estimates and an updated estimation procedure

Abstract: OBJECTIVE: To critically examine the data used to produce estimates of the proportion of infants with low birth weight in developing countries and to describe biases in these data. To assess the effect of adjustment procedures on the estimates and propose a modified estimation procedure for international reporting purposes. METHODS: Mothers' reports about their recent births in 62 nationally representative Demographic and Health Surveys (DHS) conducted between 1990 and 2000 were analysed. The proportion of infants weighed at birth, characteristics of those weighed, extent of misreporting, and mothers' subjective assessments of their children's size at birth were examined. FINDINGS: In many developing countries the majority of infants were not weighed at birth. Those who were weighed were more likely to have mothers who live in urban areas and are educated, and to be born in a medical facility with assistance from medically trained personnel. Birth weights reported by mothers are "heaped" on multiples of 500 grams. CONCLUSION: Current survey-based estimates of the prevalence of low birth weight are biased substantially downwards. Two adjustments to reported data are recommended: a weighting procedure that combines reported birth weights with mothers' assessment of the child's size at birth, and categorization of one-quarter of the infants reported to have a birth weight of exactly 2500 grams as having low birth weight. Averaged over all surveys, these procedures increased the proportion classified as having low birth weight by 25%. We also recommend that the proportion of infants not weighed at birth be routinely reported. Efforts are needed to increase the weighing of newborns and the recording of their weights.

Association or causation: evaluating links between "environment and disease"

Abstract: Epidemiological studies typically examine associations between an exposure variable and a health outcome. In assessing the causal nature of an observed association the “Bradford Hill criteria” have long provided a background framework — in the words of one of Bradford Hill’s closest colleagues an “aid to thought”. First published exactly 40 years ago these criteria also provided biomedical relevance to epidemiological research and quickly became a mainstay of epidemiological textbooks and data interpretation. Their checklist nature suited the study of simple direct causation by disciplines characterized by classic scientific and mathematical training. Most diseases have a multifactorial pathogenesis but the conceptualization of their causation varies by discipline. While it is scientifically satisfying to elucidate the many component causes of an illness in public health research the more important emphasis is on the discovery of necessary or sufficient causes that are amenable to intervention. Even so over the four decades since Bradford Hill’s paper appeared the range of multivariate multistage and multi-level research questions tackled by epidemiologists has evolved as have their statistical methods and their engagement in wider-ranging interdisciplinary research. Within that context it is often not appropriate to seek the discrete cause or causes of a disease but rather to identify a complex of interrelated and often interacting factors that influence the risk of disease. This complicates the assessment of causality. (excerpt)

World mortality 1950-2000: divergence replaces convergence from the late 1980s.

Abstract: OBJECTIVE: We sought to investigate to what extent worldwide improvements in mortality over the past 50 years have been accompanied by convergence in the mortality experience of the world's population. METHODS: We have adopted a novel approach to the objective measurement of global mortality convergence. The global mortality distribution at a point in time is quantified using a dispersion measure of mortality (DMM). Trends in the DMM indicate global mortality convergence and divergence. The analysis uses United Nations data for 1950-2000 for all 152 countries with populations of at least 1 million in 2000 (99.7% of the world's population in 2000). FINDINGS: The DMM for life expectancy at birth declined until the late 1980s but has since increased, signalling a shift from global convergence to divergence in life expectancy at birth. In contrast, the DMM for infant mortality indicates continued convergence since 1950. CONCLUSION: The switch in the late 1980s from the global convergence of life expectancy at birth to divergence indicates that progress in reducing mortality differences between many populations is now more than offset by the scale of reversals in adult mortality in others. Global progress needs to be judged on whether mortality convergence can be re-established and indeed accelerated.

Exploiting the potential of vector control for disease prevention

Abstract: Although vector control has proven highly effective in preventing disease transmission, it is not being used to its full potential, thereby depriving disadvantaged populations of the benefits of well tried and tested methods. Following the discovery of synthetic residual insecticides in the 1940s, large-scale programmes succeeded in bringing many of the important vector-borne diseases under control. By the late 1960s, most vector-borne diseases--with the exception of malaria in Africa--were no longer considered to be of primary public health importance. The result was that control programmes lapsed, resources dwindled, and specialists in vector control disappeared from public health units. Within two decades, many important vector-borne diseases had re-emerged or spread to new areas. The time has come to restore vector control to its key role in the prevention of disease transmission, albeit with an increased emphasis on multiple measures, whether pesticide-based or involving environmental modification, and with a strengthened managerial and operational capacity. Integrated vector management provides a sound conceptual framework for deployment of cost-effective and sustainable methods of vector control. This approach allows for full consideration of the complex determinants of disease transmission, including local disease ecology, the role of human activity in increasing risks of disease transmission, and the socioeconomic conditions of affected communities.