Health Of Human Populations Research Articles

Population vulnerabilities and capacities related to health: A test of a model

Variability in the health of human populations is greater in economically vulnerable areas. We tested whether this variability reflects and can be explained by: (1) underlying vulnerabilities and capacities of populations and/or (2) differences in the distribution of individual socioeconomic status between populations. Health outcomes were rates of mortality from 12 causes (cardiovascular disease, malignant neoplasms, accidents, chronic lower respiratory disease, cerebrovascular disease, pneumonia and influenza, diseases of the nervous system, suicide, chronic liver disease and cirrhosis, diabetes, homicide, HIV/AIDS) for 59 New York City neighborhoods in 2000. Negative binomial regression models were fit with a measure of socioeconomic vulnerability, median income, predicting each mortality rate. Overdispersion of each model was used to assess whether variability in mortality rates increased with increasing neighborhood socioeconomic vulnerability. To assess the two hypotheses, we examined changes in the variability of mortality rates (as indicated by changes in overdispersion of the models) for outcomes with significant non-constant variability after accounting for (1) vulnerabilities and capacities (social control, quality of local schools, unemployment, low education), and (2) the distribution of individual socioeconomic status (low income, poverty, socioeconomic distribution, high income). Some variability in all mortality rates was explained by accounting for a range of potential vulnerabilities and capacities, supporting the first explanation. However, variability in some causes of mortality was also explained in part by accounting for the distribution of individual resources, supporting the second explanation. The results are consistent with a theory of underlying socioeconomic vulnerabilities of human populations. In areas with lower levels of income, other characteristics of those neighborhoods exacerbate or temper the economic vulnerability, leading to more or less healthy conditions. Understanding the vulnerabilities and capacities that characterize populations may help us better understand the production of population health, and may inform efforts aimed at improving population health.

Educating for a healthy, sustainable world: an argument for integrating Health Promoting Schools and Sustainable Schools

Al Gore's movie An Inconvenient Truth and the British government's Stern Review of the economics of climate change have provided heightened awareness of how humans are over-stretching the Earth's life support systems. The health of human populations and the health of global ecosystems are inextricably linked and the need for fundamental changes in how we live is becoming impossible to ignore. While not the complete answer, education must be a part of imagining and transforming our patterns of living. Learning embedded in educational systems derived from worldviews that replicate unhealthy and unsustainable lifestyles and environments is not a part of the solution but a significant part of the problem. In Australia, two internationally implemented whole-school reform movements, health promoting schools (HPS) and sustainable schools (SS)--seek to provide ways of operationalizing transformative educational processes. Both movements aim to build resilience and optimism, use action-oriented teaching and learning approaches, and have a focus on the future. While these two approaches to educational and social change have much in common, currently there is virtually no conversation between their proponents and advocates. This paper makes a case for HPS and SS to work together--both theoretically and practically--with the ultimate goal being the emergence of schools that are both green and healthy. Such integration would make an important educational contribution to the creation of a healthy, sustainable world.

Effects of Low Doses of Radiation: Joint Statement from the Following Participants at the 15th Pacific Basin Nuclear Conference, Sessions Held in Sydney, Australia, Wednesday 18 October 2006

Effects of Low Doses of Radiation: Joint Statement from the Following Participants at the 15^th Pacific Basin Nuclear Conference, Sessions Held in Sydney, Australia, Wednesday 18 October 2006

A review of the nutritional value of lupins for dairy cows

Australia is the world’s leading source of lupin grain, producing ~1 million tonnes annually, of which 30% is used by the domestic livestock industry and the rest is exported for use in animal diets, including dairy cows. The domestic dairy industry uses ~70 000 tonnes annually, mainly as a supplementary feed source in pasture-based systems. Although much published information exists on the nutritive value of lupins for dairy cows, it tends to be fragmented and, in some important instances, exists only in the form of reports or publications outside the mainstream scientific journals. This paper aims to present a critical assessment of the current knowledge regarding the nutritional value of lupins as a feed for dairy cows, and offers recommendations for future research. For cows grazing pasture or fed diets based on conserved pasture or cereal hay, the mean fractional response to lupin feeding was 0.53 kg milk/kg DM lupins, with a range of 0–0.97 kg/kg. The mean fractional forage substitution rate was 0.54 kg DM/kg lupins, and this appeared to be independent of the type of basal forage. In experiments using cows fed iso-nitrogenous and iso-energetic total mixed rations, substituting oilseed protein such as soybean meal with cracked lupin grain had no significant effects on yield of milk, fat, and protein, but it reduced milk protein concentration and had mixed effects on fat concentration. There were no significant differences in milk yield or in fat or protein concentration when lupins were substituted for other pulse grains such as faba beans or peas. Treatment of lupin grain with heat or formaldehyde reduced lupin protein degradability in the rumen, but was not shown to have consistent benefits over untreated lupins in terms of increased milk yield. Substitution of cereal grains with an equivalent weight of lupins in dairy concentrate rations generally resulted in increased yield of milk, fat, and protein, and a higher fat concentration. The higher yield responses in most cases could be explained on the basis of the higher metabolisable energy content of lupins compared with cereal grains, although the contribution from a potentially lower incidence of rumen lactic acidosis could not be discounted. Feeding Lupinus albus lupins to cows significantly increased the concentration of C18 : 1 in milk and reduced that of C12 : 0–C16 : 0, thus shifting the fatty acid profile of milk towards national dietary guidelines for improved cardiovascular health in human populations. Although the review lists some recommendations for improving the nutritive value of lupins, current commercially available cultivars possess characteristics that make them attractive as a feedstuff for dairy cows.

Antioxidant and antimicrobial activities of native Rosa sp. from British Columbia, Canada

Indigenous traditional knowledge and western science have revealed the potential for significant nutritional and therapeutic benefits among natural antioxidants. We investigated antioxidant and antimicrobial activity of rose hip extracts (Rosa nutkana, Rosa pisocarpa and Rosa woodsii) from wild British Columbia populations using liposome oxidation and disc diffusion assays. All extracts exhibited strong antioxidant activity. R. nutkana pericarp extracts contained high phenolic concentrations and showed greater antioxidant and antimicrobial activity than seed extracts. R. woodsii seed extracts had a higher phenolic concentration and greater antioxidant activity than pericarp extracts. Antioxidant activity was correlated with antimicrobial activity, and both extracts showed antimicrobial activity against yeast and Gram-positive bacteria. Our study is the first to demonstrate the antioxidant and antimicrobial properties of wild British Columbia roses. The effectiveness of selected species compared with standards demonstrates the significance of this natural resource to the continued health of human populations, and the need for conservation practices.

The girl from the Church of the Sacrament: a case of congenital syphilis in XVIII century Lisbon

Syphilis is a sexually or congenitally transmitted infectious disease with an impact on the health of human populations that has undergone important cycles in different countries and periods of history. Its presence was first diagnosed in Europe in the late XIV century. In Portugal, although there are various written records of the infection in the last centuries, there are rare references to it in archeological findings (mummified bodies are also rare in Portugal). The current study describes a probable case of congenital syphilis in an 18-month-old girl buried in the Church of the Sacrament in Lisbon. Her body, dating to the XVIII century, was found mummified together with dozens of others, still not studied. Symmetrical periostitis of the long bones, osteitis, metaphyseal lesions, left knee articular, and epiphyseal destruction, and a rarefied lesion with a radiological appearance compatible with Wimberger's sign all point to a diagnosis of congenital syphilis. The diagnosis of this severe form of the infection, possibly related to the cause of death in this upper-class girl, calls attention to the disease's presence in XVIII century Lisbon and is consistent with the intense mobilization at the time in relation to the risks posed by so-called heredosyphilis. It is the first case of congenital syphilis in a child reported in archeological findings in Portugal, and can be correlated with other cases in skeletons of adults buried in cemeteries in Lisbon (in the XVI to XVIII centuries) and Coimbra (XIX century). Finally, this finding highlights the need to study the entire series of mummified bodies in the Church of the Sacrament in order to compare the paleopathological findings and existing historical documents on syphilis, so as to expand the paleoepidemiological knowledge of this infection in XVIII century Lisbon.

Investigating the health of our ancestors: Insights from the evolutionary genetic consequences of prehistoric diseases

Investigations into the health and diseases of prehistoric human populations are traditionally based on various approaches for analyzing skeletal remains. In this paper, I propose that a complementary approach, based on patterns of genetic variation in contemporary populations, can also provide insights into prehistoric health and disease. The idea is that selection for increased reproductive fitness, because of some selective force (such as resistance to a particular disease), will leave a signature on the gene(s) involved. I describe how modern genomic approaches can identify such genes, and two examples are given of genes that have clearly been influenced by selection. However, while modern genomics is making it relatively straightforward to identify genes that have been subject to selection, the challenge still remains as to how to identify the responsible selective force.

Fetal programming of hypothalamo‐pituitary‐adrenal function: prenatal stress and glucocorticoids

Prenatal stress (PS) and maternal exposure to exogenous glucocorticoids can lead to permanent modification of hypothalamo-pituitary-adrenal (HPA) function and stress-related behaviour. Both of these manipulations lead to increased fetal exposure to glucocorticoids. Glucocorticoids are essential for many aspects of normal brain development, but exposure of the fetal brain to an excess of glucocorticoids can have life-long effects on neuroendocrine function. Both endogenous glucocorticoid and synthetic glucocorticoid exposure have a number of rapid effects in the fetal brain, including modification of neurotransmitter systems and transcriptional machinery. Such fetal exposure permanently alters HPA function in prepubertal, postpubertal and ageing offspring, in a sex-dependent manner. Prenatal stress and exogenous glucocorticoid manipulation also lead to the modification of behaviour, brain and organ morphology, as well as altered regulation of other endocrine systems. It is also becoming increasingly apparent that the timing of exposure to PS or synthetic glucocorticoids has tremendous effects on the nature of the phenotypic outcome. Permanent changes in endocrine function will ultimately impact on health in both human and animal populations.

Climate Change and Human Health: Estimating Avoidable Deaths and Disease

Human population health has always been central in the justification for sustainable development but nearly invisible in the United Nations Framework Convention on Climate Change negotiations. Current scientific evidence indicates that climate change will contribute to the global burden of disease through increases in diarrhoeal disease, vector-borne disease, and malnutrition, and the health impacts of extreme weather and climate events. A few studies have estimated future potential health impacts of climate change but often generate little policy-relevant information. Robust estimates of future health impacts rely on robust projections of future disease patterns. The application of a standardized and established methodology has been developed to quantify the impact of climate change in relation to different greenhouse gas emission scenarios. All health risk assessments are necessarily biased toward conservative best-estimates of health effects that are easily measured. Global, regional, and national risk assessments can take no account of irreversibility, or plausible low-probability events with potentially very high burdens on human health. There is no "safe limit" of climate change with respect to health impacts as health systems in some regions do not adequately cope with the current climate variability. Current scientific methods cannot identify global threshold health effects in order for policymakers to regulate a "tolerable" amount of climate change. We argue for the need for more research to reduce the potential impacts of climate change on human health, including the development of improved methods for quantitative risk assessment. The large uncertainty about the future effects of climate change on human population health should be a reason to reduce greenhouse gas emissions, and not a reason for inaction.

Transitions in a globalising world

The increasing complexity of our global society means that sustainable development cannot be addressed from a single perspective or scientific discipline. By using the concept of transitions, we examine current and future tensions between welfare, well-being and the environment, and focus on four major issues that are of global importance: two of our key natural resources, water and biodiversity; the health of human populations; and the developments related to global tourism. In our global assessment, we base ourselves on the most recent scenario efforts of the Intergovernmental Panel on Climate Change (IPCC). Future developments are explored along the lines of four development paths (scenario groups), defined along two dimensions (global versus regional dynamics and emphasising economic objectives versus environmental and equity objectives.

A model of underlying socioeconomic vulnerability in human populations: evidence from variability in population health and implications for public health

Drawing from insights into the variability of complex biologic systems we propose that the health of human populations reflects the interrelationship between underlying vulnerabilities (determined by population-level social and economic factors; e.g., income distribution) and capacities (determined by population-level salutary resources, e.g., social capital) and how populations, shaped by these vulnerabilities and capacities, respond to intermittent stressors (e.g., economic downturns) and protective events (e.g., introduction of a school). Monitoring this dynamic at the population-level can be accomplished by examining not only rates of illness and mortality, but variability in rates, either between populations or within populations over time. We used mortality data from New York City neighborhoods between 1990 and 2001 to test two related hypotheses consistent with this model of population health: (a) There is greater variability in mortality rates at a point in time between neighborhoods that are characterized by socioeconomic vulnerability; and (b) there is greater variability in mortality rates over time within neighborhoods that are characterized by socioeconomic vulnerability. We found that neighborhoods characterized by social and economic vulnerability displayed substantial variability in particular mortality rates. Mortality rates displaying the greatest variability were from causes that may be sensitive to social conditions (e.g., homicide or HIV/AIDS rates). Variability in population health existed both between neighborhoods with underlying vulnerability at one point in time and within vulnerable neighborhoods over time. The results of this analysis are consistent with a theory of underlying socioeconomic vulnerabilities of human populations and suggest that variability in population health may be an important consideration in population health assessment.

Summary of a Workshop on the Development of Health Models and Scenarios: Strategies for the Future

A workshop was convened in July 2003 by the Global Change Research Program, Office of Research and Development at the U.S. Environmental Protection Agency, to review current strategies for developing human health models and scenarios in the context of global environmental change, particularly global climate change, and to outline a research agenda that effectively characterizes the interplay of global change with the health of human populations. The research agenda developed at the workshop focused on three issues: a) the development of health models, b) the development of health scenarios, and c) the use of health models and health scenarios to inform policy. The agenda identified research gaps as well as barriers to the development and use of models and scenarios. This report summarizes the workshop findings.

Ciclo de vida de Culex quinquefasciatus Say, 1826 (Diptera: Culicidae) bajo condiciones no controladas en Bogotá.

Aspects of the growth and development were described for immature stages of Culex quinquefasciatus Say, 1826 (Diptera: Culicidae), an antropophilic mosquito species found frequently in Bogotá, Colombia. Two experiments were carried out during January-February and September-October of 2001 under ambient environmental conditions. Oviposition occured 5-8 days after blood ingestion. Females laid eggs in plastic containers filled with pooled water with high organic material content. The number of eggs per raft varied between 152 and 203. For the 2 trials, the hatch rate was 50% and 75%. The asynchronous egg hatch, the short duration of the pupal stage (11% of the total development time, and the high efficiency of adult emergence from the pupal stage (98.6%) were noted. In general, these development times were shorter compared to those reported by other authors. Moreover, the high percentages of hatch (83.6%), pupation (86.6%) and emergence (98.6%) under the average temperature conditions of 14.8 degrees C and 15.1 degrees C, and average relative humidity of 72.5% and 74.1%, respectively) demonstrated adaptation of C. quinquefasciatus to Bogotá's cool, high altitude environment. These characteristics, together with its vectorial capacity and the resistance to chemical control methods, could make this species become a risk for the health of human populations.

IMMUNE SYSTEMS, GEOGRAPHIC INFORMATION SYSTEMS (GIS), ENVIRONMENT AND HEALTH IMPACTS

Exposure to dioxins, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) has been related to alterations in cellular and humoral immune responses in both adaptive and innate immune systems of most animal species. These compounds share a common signaling mechanism to exert their effects on cells of the immune system, which includes the aryl-hydrocarbon receptor (AhR) and the AhR nuclear translocator (ARNT). Recently, the interference of AhR–ARNT with the nuclear factor (NF)-κB signaling pathway has been proposed as a critical event in the adverse effects on the immune system. Studies on the effects of these AhR–ARNT-related toxicants on the immune system of higher and lower phylum animals and knowledge of intracellular mechanisms of toxicity may contribute to development of biomarkers of ecotoxicant exposure and effects. Biomarkers of this kind allow sampling over extended geographic areas, in several sentinel species, including wildlife animals, and facilitate the building of risk models and risk maps of environmentally induced diseases. On the basis of location, biomarker sampled data obtained through evaluation of ecotoxicant exposure and effects on the immune system in sentinel species can be further integrated and analyzed together with other sources of environmental geographic information, or human population health data, by means of geographic information systems (GIS). The spatial analysis capability of GIS can help to evaluate the complex relationships of overlaid information and to identify areas with high risk indices or “hot spots.” This integrative approach can be useful in studies contributing to support environmental and health-related policies and regulations.

A Pediatric Perspective on the Unique Vulnerability and Resilience of the Embryo and the Child to Environmental Toxicants: The Importance of Rigorous Research Concerning Age and Agent

There is realistic concern about the impact of environmental influences on the health of human populations. First, exposure to environmental agents continues despite successes in reducing exposures to known toxicants such as lead, polychlorinated biphenyls (PCBs) and tobacco smoke. Second, there has been increasing concern about the cause of autism and other neurodevelopmental problems and hypotheses that environmental influences may play a role in the prevalence of these and other such childhood and adult conditions as asthma and obesity. Third, many other conditions are directly or indirectly related to environmental influences and are preventable, such as injuries, untoward consequences of alcohol, suicide, drug addiction, and gun-related deaths. There have been numerous publications since the 1970s of symposia, proceedings, monographs, and articles dealing with the increased susceptibility of the embryo, infant, and child to environmental toxicants,1–17 reflecting a greater level of concern about embryonic and childhood exposures. Indeed, great deal of attention has been paid to the vulnerability of the embryo and the fetus to environmental chemicals, drugs, and physical agents. In fact, the publication edited by Miller1 was primarily devoted to exposures to the embryo and the fetus. Because the embryo and the child are growing and their tissues and organs are differentiating, deleterious effects may occur at lower exposures to some chemicals, drugs, and physical agents and produce more severe effects than those seen in adults. In fact, some effects may not occur in adults. Thus, maximal permissible exposures (MPEs) for some environmental chemicals should be lower for the embryo and the child. It is important to note that children and adolescents have better recuperative capacities than adults for many toxic agents, and, similarly, appropriate drug dosages may be lower or higher on a mg/kg or surface area basis in children than in adults to … Reprint requests to (R.L.B.) Rm 308, R/A, Alfred I. duPont Hospital for Children, Box 269, Wilmington, DE 19899. E-mail: rbrent{at}nemours.org

Science and social responsibility in public health.

Epidemiologists and environmental health researchers have a joint responsibility to acquire scientific knowledge that matters to public health and to apply the knowledge gained in public health practice. We examine the nature and source of these social responsibilities, discuss a debate in the epidemiological literature on roles and responsibilities, and cite approaches to environmental justice as reflective of them. At one level, responsibility refers to accountability, as in being responsible for actions taken. A deeper meaning of responsibility corresponds to commitment to the pursuit and achievement of a valued end. Epidemiologists are committed to the scientific study of health and disease in human populations and to the application of scientific knowledge to improve the public's health. Responsibility is also closely linked to reliability. Responsible professionals reliably perform the tasks they set for themselves as well as the tasks society expects them to undertake. The defining axiom for our approach is that the health of the public is a social good we commit ourselves to pursue, thus assuming an obligation to contribute to its achievement. Epidemiologists cannot claim to be committed to public health as a social good and not accept the responsibility of ensuring that the knowledge gained in their roles as scientists is used to achieve that good. The social responsibilities of environmental health researchers are conspicuous in the environmental justice movement, for example, in community-based participatory research. Responsibility is an ethical concept particularly well suited to frame many key aspects of the ethics of our profession.

Compensatory Reserves of the Human Body and Population Health under Conditions of Exposure to Chronic Anthropogenic Factors and Prolonged Psychoemotional Stress

Long-term exposure to adverse factors of various origin and intensity is expected to cause a significant decrease in the compensatory reserves and adaptive capacity of the human body. These changes deteriorate the population health status in general. A quantitative method of evaluation of the decrease in the compensatory reserves and adaptive capacity, as well as the resistance to chronic exposure to extreme factors of various origin and intensity, was developed. This method is based on the concept of stress and programmable nonspecific physiological reactions of the human body put forward by H. Selye. Model analytical curves of the time-related decrease in the volume of compensatory reserves and the increase in the probability of development of adaptive disorders and failure of the adaptation process were calculated for the cases of long-term exposure to various stressors (the factors were applied individually or in combination). This method allowed the levels of population health risk induced by various factors to be compared to each other. This is of particular importance under conditions of the existing trend toward an increase in the intensity of anthropogenic stress factors against the background of long-term psychoemotional stress. Statistical data on changes in the rates of morbidity and mortality and the life expectancy of Russian people for the period 1960–2000 were analyzed. The levels of risk of the negative impact on population health induced by various stress factors (radiation, chemical environmental pollution, and long-term psychoemotional stress) were compared to each other.

Pilot plant for bioremediation of mercury-containing industrial wastewater.

Mercury is an extremely toxic pollutant that is currently being emitted mainly by low level industrial sources. It is distributed globally through the atmosphere, from where it precipitates onto the surface of the Earth, enters aquatic organisms, accumulates in fish and finally affects the health of human populations. Microbes have evolved a mechanism for mercury detoxification [mercury resistance operon ( mer)] based on intracellular reduction of Hg(2+) to non-toxic Hg(0) by the mercuric reductase enzyme and subsequent diffusional loss of Hg(0) from the cell. It was shown that Hg(0) produced by microbial detoxification can be retained quantitatively in packed bed bioreactors, in which biofilms of mercury-resistant bacteria are grown on porous carrier material. This review describes operation of this system on a technical, fully automated, scale, and its operation at a chloralkali electrolysis factory. It was shown to work with high efficiency under fluctuating mercury concentrations and to be robust against transiently toxic conditions. The gradient of mercury concentration in the technical scale system exerted a strong selective pressure on the microbial community, which resulted in a succession of mercury-resistant strains at high mercury concentrations and an increase in phylogenetic and functional diversity at low mercury concentrations. Clean-up of mercury-containing wastewater by mercury-resistant microbes is a simple, environmentally friendly and cost-effective alternative to current treatment technologies.

Environmental Health Surveillance: Indicators for Freshwater Ecosystems

The relationship between the health of human populations and the state of the ecosystems in which they live is profoundly complex. As most environmental indicators relevant to human health depend on evidence of a direct cause and effect relationship, there are few indicators of the less direct consequences of environmental degradation on human health. Indicators of the direct consequence of contaminants in freshwater ecosystems on human health are highlighted in this paper and candidate indicators for environmental health are provided. Many of the indicators included here are from the State Of the Lakes Ecosystem Conference (SOLEC) program. SOLEC conferences in the past (1994 and 1996) examined the state of various components of the ecosystem through the use of ad hoc indicators, and provided subjective assessments of certain environmental conditions. At SOLEC 98, a comprehensive suite of 80 Great Lakes ecosystem health indicators was presented for review, refinement and acceptance. Candidate indicators for freshwater systems and environmental health presented here are organized following the "Pressure-State-Response" framework and cover the areas of drinking water, recreational water, freshwater food sources, and the availability of freshwater for economic activities.

Factors associated with oxidative stress in human populations.

Oxidation of biomolecules may play a role in susceptibility to a number of diseases. However, there are few large-scale survey data describing oxidative damage that occurs in humans and the demographic, physical, or nutritional factors that may be associated with it. Such information is essential for the design and analysis of studies investigating the role of oxidative stress in health and disease. This paper presents data on levels of two biomarkers of lipid peroxidation, malondialdehyde and F(2)-isoprostanes, in 298 healthy adults aged 19-78 years. The study was conducted in Berkeley and Oakland, California, in 1998-1999. Sex was the strongest predictor of lipid peroxidation as measured by both biomarkers (p < 0.0001); it was stronger than smoking. C-reactive protein was positively associated with lipid peroxidation (p = 0.004), as was plasma cholesterol. Plasma ascorbic acid had a strong inverse relation (p < 0.001) with both biomarkers. Plasma beta-carotene was also associated with F(2)-isoprostanes. Other plasma antioxidants were not associated with lipid peroxidation biomarkers, once ascorbic acid was included in the multivariate model. Future surveys and epidemiologic studies should measure at least one marker of oxidative damage, as well as plasma ascorbic acid. These data would permit a better understanding of the role that oxidants and antioxidants play in the health of human populations.