Schools for health: Focus on health, education and the school-age child

Mortality in children under five years old has been dramatically reduced through successful programmes of immunization and control of diarrhoeal diseases. UNICEF estimates that some 90% of children in developing regions now survive to reach school age. These survivors face new and continuing threats to their health, which can affect their physical development and may also prevent them taking full advantage of their only opportunity for formal education. The physical and mental growth of the 1000 million school-age children today will influence how the world is shaped for coming generations. Yet the health problems of this age group have received little attention. Recognizing the importance of this age group, a workshop funded by the Edna McConnell Clark Foundation was held 10-13 November 1994 in Fort Mitchell, Kentucky, USA, to review what is known about the health of school-age children, what is or can be done to improve their health, and what steps must be taken to find ways to improve the health and educational achievement of this important segment of the world's population. Don Bundy and Helen Guyatt here report on the workshop, which had three major conclusions: (1) the school-age children of developing countries face health problems that remain neglected and poorly understood; (2) an important research need is to develop simpler means of monitoring the health status of school-age children and evaluating the impact of public health interventions in this age group; and (3) two strategies are available to address this public health problem. The first is to develop further and test programmes that appear, from available evidence and pilot studies, to offer effective means of improving the health of this age group at reasonable cost, and to be sustainable; and the second is, over a longer term, to develop the capacity within countries to assess the health problems of school-age children and devise cost-effective strategies to address these problems. This report attempts, in brief form, to survey what is known about the health status of school-age children, to discuss the possible benefits to health and learning that accrue from health interventions, and to suggest some avenues currently available for both research and application.     

Environmental hazards to children's health in the modern world

Patterns of illness in children have changed dramatically in the last century, and will continue to change in this century. The major diseases confronting children are now chronic and disabling conditions termed the "new pediatric morbidity"-asthma, leukemia and brain cancer, neurodevelopmental dysfunction and neurobehavioral abnormality, reproductive and systemic developmental problems. Chemical toxicants in the environment, poverty, and little or no access to health care are all factors contributing to life-threatening pediatric diseases; children are uniquely vulnerable to chemical toxicants because of their disproportionately heavy exposures and their inherent biological growth and development. Genetic susceptibility and environmental exposures during vulnerable periods of development are also important contributors to the etiologies of many diseases of childhood. It is vital that we develop a better understanding of the mechanisms and interactions between nutrition, infectious disease, environmental exposures, and genetic predisposition in order to develop better prevention methods. This paper briefly examines modern contributors to children's environmental health problems, efforts to date on both the regional and international level to address these challenges, and reflects upon major research needs that must be addressed in order to close the gaps that exist in our understanding of the relationship between environmental exposures and children's health.     

Evolution of virulence,environmental change,and the threat posed by emerging and chronic diseases

Assessments of future threats posed by infection have focused largely on zoonotic, acute disease, under the rubric “emerging diseases.” Evolutionary and epidemiological studies indicate, however, that particular aspects of infrastructure, such as protected water supplies, vector-proof housing, and health care facilities, protect against the emergence of zoonotic, acute infectious diseases. While attention in the global health community has focused on emerging diseases, there has been a concurrent, growing recognition that important chronic diseases, such as cancer, are often caused by infectious agents that are already widespread in human populations. For economically prosperous countries, the immediacy of this threat contrasts with their infrastructural protection from severe acute infectious disease. This reasoning leads to the conclusion that chronic infectious diseases pose a more significant threat to economically prosperous countries than zoonotic, acute infectious diseases. Research efforts directed at threats posed by infection may therefore be more effective overall if increased efforts are directed toward understanding and preventing infectious causes of chronic diseases across the spectrum of economic prosperity, as well as toward specific infrastructural improvements in less prosperous countries to protect against virulent, acute infectious diseases.     

Are there Characteristics of Infectious Diseases that Raise Special Ethical Issues?1

This paper examines the characteristics of infectious diseases that raise special medical and social ethical issues, and explores ways of integrating both current bioethical and classical public health ethics concerns. Many of the ethical issues raised by infectious diseases are related to these diseases' powerful ability to engender fear in individuals and panic in populations. We address the association of some infectious diseases with high morbidity and mortality rates, the sense that infectious diseases are caused by invasion or attack on humans by foreign micro-organisms, the acute onset and rapid course of many infectious diseases, and, in particular, the communicability of infectious diseases. The individual fear and community panic associated with infectious diseases often leads to rapid, emotionally driven decision making about public health policies needed to protect the community that may be in conflict with current bioethical principles regarding the care of individual patients. The discussion includes recent examples where dialogue between public health practitioners and medical-ethicists has helped resolve ethical issues that require us to consider the infected patient as both a victim with individual needs and rights and as a potential vector of disease that is of concern to the community.     

Parasite risk factors for stunting in grade 5 students in a community of extreme poverty in Peru

Malnutrition in school-age children is common in developing countries and includes both stunting and underweight. Stunting, which represents a chronic state of nutritional stress, leads to adverse health, educational and cognitive effects. Although much research is focused on preschool-age children, recent studies show both the high prevalence of stunting and the effectiveness of interventions in school-age children. The objectives of the current study were to determine the risk factors for stunting only, and stunting and underweight. A survey was conducted in 1074 grade 5 children (mean age 10 years) from 17 schools in Belen, Peru, a community of extreme poverty. Prevalence of underweight and stunting were 10.5 and 34.5%, respectively, co-prevalence was 9.3%. Based on multivariable logistic regression analyses, significant independent risk factors (odds ratio: OR) for stunting and underweight were: age (per 1 year increment) (OR=1.55; 95% confidence interval (CI): 1.33, 1.81); diarrhoea in the last week (OR=1.96; 95% CI: 1.17, 3.29) and hookworm infection (OR=1.74; 95% CI: 1.05, 2.86). Significant independent risk factors for stunting only were: age (per 1 year increment) (OR=1.51; 95% CI: 1.35, 1.70); anaemia (OR=1.98; 95% CI: 1.26, 3.11); and moderate and heavy Trichuris and Ascaris co-infection (OR=1.95; 95% CI: 1.35, 2.82). Our results indicate a high prevalence of stunting, in addition to other adverse health indicators, in the study population. Due to the interrelation between many of these health and nutrition problems, interventions at both the school and community levels, including de-worming, feeding programs and health and hygiene education, are needed to reduce malnutrition in this and other similar populations living in conditions of extreme poverty.     

Cultural Variation—Nutritional and Clinical Implications

Cultural variation may play an important role in human nutrition and must be considered in either clinical or public health intervention particularly in areas with large immigrant populations. Acculturative and environmental change influence the food habits and health of transitional groups. Nutritional assessment may be complicated by cultural variation. The relationship between ethnicity and nutrition may be of evolutionary significance. Food beliefs may have beneficial or detrimental effects on health status. The study of acculturating populations may elucidate the pathogenesis of nutrition-related chronic diseases. Appreciation of the interaction of culture and nutrition may be of benefit to physicians and nutritionists in clinical practice and to those concerned with the prevention of nutrition-related chronic diseases.     

Determinants of emerging and re-emerging infectious diseases.

In the 1960s and 1970s, many public health experts assumed that infectious diseases could at long last be conquered as had occurred with smallpox. In the last two decades, reports warned that infectious diseases were clearly not a problem of the past. They could not be considered as a unique or isolated event of wild and faraway regions, but penetrated every corner of the globe. Emerging infectious diseases have been recently described as clinically distinct conditions whose incidence in humans has increased regionally or worldwide within the past two decades. Emergence may be due to the introduction of new agents to or the recognition of an existing disease that has gone undetected, and re-emergence may describe the re-appearance of known diseases after a decline in incidence. In this article a global, multidisciplinary and integrated approach in different fields of demography, epidemiology, economy, ecology, anthropology and environment at science has been considered to describe the different determinants responsible for the emergence and re-emergence of infectious diseases.     

Life History theory hypotheses on child growth: Potential implications for short and long‐term child growth,development and health

Life history theory integrates ecological, physiological, and molecular layers within an evolutionary framework to understand organisms’ strategies to optimize survival and reproduction. Two life history hypotheses and their implications for child growth, development, and health (illustrated in the South African context) are reviewed here. One hypothesis suggests that there is an energy trade‐off between linear growth and brain growth. Undernutrition in infancy and childhood may trigger adaptive physiological mechanisms prioritizing the brain at the expense of body growth. Another hypothesis is that the period from conception to infancy is a critical window of developmental plasticity of linear growth, the duration of which may vary between and within populations. The transition from infancy to childhood may mark the end of a critical window of opportunity for improving child growth. Both hypotheses emphasize the developmental plasticity of linear growth and the potential determinants of growth variability (including the role of parent–offspring conflict in maternal resources allocation). Implications of these hypotheses in populations with high burdens of undernutrition and infections are discussed. In South Africa, HIV/AIDS during pregnancy (associated with adverse birth outcomes, short duration of breastfeeding, and social consequences) may lead to a shortened window of developmental plasticity of growth. Furthermore, undernutrition and infectious diseases in children living in South Africa, a country undergoing a rapid nutrition transition, may have adverse consequences on individuals’ cognitive abilities and risks of cardio‐metabolic diseases. Studies are needed to identify physiological mechanisms underlying energy allocation between biological functions and their potential impacts on health.     

免疫抑制剂治疗对儿童疫苗诱导的免疫保护性的影响及其相关机制

疫苗是目前公认的预防传染病的有效手段,接种疫苗可极大降低人群传染病的发病率和病死率。随着现代医学的进展,接受免疫抑制剂治疗肿瘤、器官移植、造血干细胞移植及慢性病的患儿生存率有了很大提高,但免疫抑制剂的使用会影响疫苗诱导的免疫保护效果及儿童时期疫苗接种的安全性,使这部分免疫低下的特殊儿童成为疫苗可预防疾病的高危易感人群。本文综述了免疫抑制剂对儿童疫苗免疫保护性的影响及其相关机制。     

The hidden penalties of gender inequality: fetal origins of ill-health

This paper is concerned with the interconnections between gender inequality and maternal deprivation, on the one hand, and the health of children (of either sex) and of adults that the children grow into (again, of either sex). The basic message of the paper is that women's deprivation in terms of nutrition and healthcare rebounds on the society as a whole in the form of ill-health of their offspring-males and females alike-both as children and as adults. There are a variety of pathways through which women's deprivation can affect the health of the society as a whole. This paper focuses on the pathways that operate through undernourishment of the mother. Maternal deprivation adversely affects the health of the fetus, which in turn leads to long-term health risks that extend not just into childhood but into adulthood as well. There are, however, important differences in the way children and adults experience the consequences of maternal deprivation via fetal deprivation. In particular, the pathways that lead to their respective risk factors and the circumstances under which those risk factors actually translate into ill-health are very different. These differences are best understood through the concept of 'overlapping health transition' in which two different regimes of diseases coexist side by side. Gender inequality exacerbates the old regime of diseases among the less affluent through the pathway of childhood undernutrition. At the same time it also exacerbates the new regime of diseases among the relatively more affluent through a pathway that has come to be known as the 'Barker hypothesis'. Gender inequality thus leads to a double jeopardy-simultaneously aggravating both regimes of diseases and thus raising the economic cost of overlapping health transition.     

Optimal Timing of Disease Transmission in an Age-Structured Population

It is a common medical folk-practice for parents to encourage their children to contract certain infectious diseases while they are young. This folk-practice is controversial, in part, because it contradicts the long-term public health goal of minimizing disease incidence. We study an epidemiological model of infectious disease in an age-structured population where virulence is age-dependent and show that, in some cases, the optimal behavior will increase disease transmission. This provides a rigorous justification of the concept of “endemic stability,” and demonstrates that folk-practices may have been historically justified.     

Impact of long-term treatment with ivermectin on the prevalence and intensity of soil-transmitted helminth infections

Background

Control of soil-transmitted helminth (STH) infections relies on the periodic and long-term administration of anthelmintic drugs to high-risk groups, particularly school-age children living in endemic areas. There is limited data on the effectiveness of long-term periodic anthelmintic treatment on the prevalence of STHs, particularly from operational programmes. The current study investigated the impact of 15 to 17 years of treatment with the broad-spectrum anthelmintic ivermectin, used for the control of onchocerciasis, on STH prevalence and intensity in school-age and pre-school children.

Methods and Findings

A cross-sectional study was conducted in communities that had received annual or twice-annual ivermectin treatments and geographically adjacent communities that had not received treatment in two districts of Esmeraldas Province in Ecuador. Stool samples were collected from school-age children and examined for STH infection using the Kato-Katz and formol-ether concentration methods. Samples were collected also from pre-school children and examined by the formol-ether concentration method. Data on risk factors for STH infection were collected by parental questionnaire. We sampled a total of 3,705 school-age children (6–16 years) from 31 treated and 27 non-treated communities, and 1,701 pre-school children aged 0–5 years from 18 treated and 18 non-treated communities. Among school-age children, ivermectin treatment had significant effects on the prevalence (adjusted OR =  0.06, 95% CI 0.03–0.14) and intensity of Trichuris trichiura infection (adjusted RR = 0.28, 95% CI 0.11–0.70), but appeared to have no impact on Ascaris lumbricoides or hookworm infection. Reduced prevalence and intensities of T. trichiura infection were observed among children not eligible to receive ivermectina, providing some evidence of reduced transmission of T. trichiura infection in communities receiving mass ivermectin treatments.

Conclusion

Annual and twice-annual treatments with ivermectin over a period of up to 17 years may have had a significant impact on T. trichiura infection. The present data indicate that the long-term control of onchocerciasis with ivermectin may provide additional health benefits by reducing infections with trichuriasis. The addition of a second anthelmintic drug such as albendazole may be useful for a long-term effect on A. lumbricoides infection.     

微生态制剂在老年人肠道菌群失衡中的应用

人类从青年到老年这个过程,随着年龄的增长,退行性和感染性疾病的易感性也增加,其可能与人体肠道菌群失衡有着密切的关系。人体肠道内生理菌群对机体健康具有重要的作用,其变化与宿主的免疫功能、食物、疾病和年龄等有关。了解老年人肠道菌群特点,且在老年人肠道菌群失调相关疾病中合理介入微生态制剂,将大大有利于老年人身体健康。本文就老年人肠道菌群失衡相关疾病以及微生态制剂在这些疾病中的应用进行综述。     

Urogenital schistosomiasis infection prevalence targets to determine elimination as a public health problem based on microhematuria prevalence in school-age children

BackgroundRecent research suggests that schistosomiasis targets for morbidity control and elimination as a public health problem could benefit from a reanalysis. These analyses would define evidence-based targets that control programs could use to confidently assert that they had controlled or eliminated schistosomiasis as a public health problem. We estimated how low Schistosoma haematobium infection levels diagnosed by urine filtration in school-age children should be decreased so that microhematuria prevalence was at, or below, a “background” level of morbidity.MethodologyData obtained from school-age children in Burkina Faso, Mali, Niger, Tanzania, and Zambia who participated in schistosomiasis monitoring and evaluation cohorts were reanalyzed before and after initiation of preventive chemotherapy. Bayesian models estimated the infection level prevalence probabilities associated with microhematuria thresholds ≤10%, 13%, or 15%.Principal findingsAn infection prevalence of 5% could be a sensible target for urogenital schistosomiasis morbidity control in children as microhematuria prevalence was highly likely to be below 10% in all surveys. Targets of 8% and 11% infection prevalence were highly likely to result in microhematuria levels less than 13% and 15%, respectively. By contrast, measuring heavy-intensity infections only achieves these thresholds at impractically low prevalence levels.Conclusions/significanceA target of 5%, 8%, or 11% urogenital schistosomiasis infection prevalence in school-age children could be used to determine whether a geographic area has controlled or eliminated schistosomiasis as a public health problem depending on the local background threshold of microhematuria.     

After 2015: infectious diseases in a new era of health and development

Running over timescales that span decades or centuries, the epidemiological transition provides the central narrative of global health. In this transition, a reduction in mortality is followed by a reduction in fertility, creating larger, older populations in which the main causes of illness and death are no longer acute infections of children but chronic diseases of adults. Since the year 2000, the Millennium Development Goals (MDGs) have provided a framework for accelerating the decline of infectious diseases, backed by a massive injection of foreign investment to low-income countries. Despite the successes of the MDGs era, the inhabitants of low-income countries still suffer an enormous burden of disease owing to diarrhoea, pneumonia, HIV/AIDS, tuberculosis, malaria and other pathogens. Adding to the predictable burden of endemic disease, the threat of pandemics is ever-present and global. With a view to the future, this review spotlights five aspects of the fight against infection beyond 2015, when the MDGs will be replaced by a new set of goals for poverty reduction and sustainable development. These aspects are: exploiting the biological links between infectious and non-infectious diseases; controlling infections among the new urban majority; enhancing the response to international health threats; expanding childhood immunization programmes to prevent acute and chronic diseases in adults; and working towards universal health coverage. By scanning the wider horizon now, infectious disease specialists have the chance to shape the post-2015 era of health and development.     

The Shifting Demographic Landscape of Pandemic Influenza

Background

As Pandemic (H1N1) 2009 influenza spreads around the globe, it strikes school-age children more often than adults. Although there is some evidence of pre-existing immunity among older adults, this alone may not explain the significant gap in age-specific infection rates.

Methods and Findings

Based on a retrospective analysis of pandemic strains of influenza from the last century, we show that school-age children typically experience the highest attack rates in primarily naive populations, with the burden shifting to adults during the subsequent season. Using a parsimonious network-based mathematical model which incorporates the changing distribution of contacts in the susceptible population, we demonstrate that new pandemic strains of influenza are expected to shift the epidemiological landscape in exactly this way.

Conclusions

Our analysis provides a simple demographic explanation for the age bias observed for H1N1/09 attack rates, and suggests that this bias may shift in coming months. These results have significant implications for the allocation of public health resources for H1N1/09 and future influenza pandemics.     

Public health activities for ensuring adequate sleep among school-age children: current status and future directions

Sleep and Biological Rhythms - This paper reviews epidemiological findings on sleep problems among school-age children and discusses the current status and future directions of public health...     

Health transition: examples from the western Pacific.

The Industrial Revolution ushered in a rapid transition from agriculture to industrialization. Some biological effects of this transition included increasing life expectancy, reduced infant mortality, and some decline in fertility. Reduced infant mortality first brought about an increase in life expectancy, but as humans were able to control infectious diseases, child and adult mortality also decreased. Now, accidents and chronic diseases are responsible for most mortality in many age groups. This shift from infectious diseases to accidents and chronic diseases is called the health transition. Japan and US are Pacific Basin countries which have relatively high life expectancy and low infant mortality (1988, 75.54 years vs. 71.38 years, and 4.4 vs. 9.9, respectively). These figures suggest that these countries rather advanced in the health transition. Japan may have better life expectancy than the US because of the effect of environmental factors, ethnic diversity, and health care differentials by social class on cardiovascular disease and cancer mortality. China and Thailand hold intermediate positions (67.98 years (1985-1990) vs. 63.82 years (1985-1986), and 32.4 vs. 39, respectively). Some research indicates that urban conditions and factory work increase the cardiovascular disease risk among the Chinese. Recent research suggests that access to immunization and modern medical care for acute disease are the only critical variables of the health transition rather than other variables. Papua New Guinea is not progressing very well (53.18 years and 58). Papua New Guinea has not yet been able to control infectious diseases, especially malaria. This comparison illustrates that populations progress through the health transition at different rates.     

Attaining the minimum target of resolution WHA 54.19 for schistosomiasis control in the Rainforest Zone of the state of Pernambuco, Northeastern Brazil

Resolution 19 of the 54th World Health Assembly (WHA-54.19) urged member nations to promote preventive measures, ensure treatment and mobilize resources for control of schistosomiasis and soil-transmitted helminthiases (STH). The minimum target is to attend 75% of all school-age children at risk by year 2010. The Brazilian Ministry of Health (MoH) recommends biennial surveys of whole communities and treatment of the positives through the Schistosomiasis Control Program within the Unified Health System (PCE-SUS). However, by 2004 the PCE-SUS had covered only 8.4% of the 1.2 million residents in the Rainforest Zone of Pernambuco (ZMP). Six of the 43 municipalities still remained unattended. Only three of the municipalities already surveyed reached coverage of 25% or more. At least 154 thousand children in the 7-14 years old range have to be examined (and treated if positive) within the next five years to attend the minimum target of the WHA 54.19 for the ZMP. To make this target feasible, it is suggested that from 2006 to 2010 the PCE-SUS actions should be complemented with school-based diagnosis and treatment, involving health and educational organs as well as community associations to include both children in schools and non-enrolled school-age children.