Reduction Of Environmental Exposure Research Articles

Testing direct and indirect effects of green space availability on reproductive outcomes

Background/Aim:Adverse reproductive effects can lead to cognitive development problems, medical conditions, morbidity and mortality in future stages of lives. Surrounding residential greenness has a positive effect in reproductive health. Different studies have proposed that this effect could be both direct and indirect. Indirect effects of greenness may happen through the reduction of environmental exposure (air pollution, noise and temperature regulation), the promotion of physical activity and the improvement of psychological health. The aim of the study was to analyze the relationship between surrounding residential greenness and reproductive health, studying the possible role of said mediators.Methods:441 pregnant women (mean age 33.52, SD = 4.88) were recruited in Donostialdea, Basque Country, Spain, during the first ultrasound in the Basque Health Service. After signing the informed consent form, participants were given the study questionnaire and one accelerometer (ActiGraph GT3X-BT) which they used it for one week. In the second trimester of pregnancy they repeated the whole process again. Environmental exposures (NO2 and availability of >5000 m2 green space in 300m) were assigned to all participants. Moderate to Vigorous Physical Activity (MVPA) was determined with the accelerometer. Psychological health was measured with the General Health Questionnaire (GHQ-12). Birth weight, preterm birth, small and large for gestational age (SGA & LGA) were defined as outcome variables and newborn sex, season, deprivation index and parity as covariates. Natural effects models were used to analyze aforementioned direct and indirect effects.Results:Greenness availability had a negative effect on birth weight (-138g; p-value = 0.022). A marginal protective effect of greenness availability on LGA (OR = 0.54; p-value = 0.091) was detected in the model with GHQ as mediator.Conclusions:Greenness availability in 300m had limited effects on reproductive outcomes. Using other measures of greenness may help to understand this question better.

Residential green space and pathways to term birth weight in the Canadian Healthy Infant Longitudinal Development (CHILD) Study

BackgroundA growing number of studies observe associations between the amount of green space around a mother’s home and positive birth outcomes; however, the robustness of this association and potential pathways of action remain unclear.ObjectivesTo examine associations between mother’s residential green space and term birth weight within the Canadian Healthy Infant Longitudinal Development (CHILD) study and examine specific hypothesized pathways.MethodsWe examined 2510 births located in Vancouver, Edmonton, Winnipeg, and Toronto Canada. Green space was estimated around mother’s residences during pregnancy using Landsat 30 m normalized difference vegetation index (NDVI). We examined hypothesized pathways of: (1) reduction of environmental exposure; (2) built environment features promoting physical activity; (3) psychosocial conditions; and (4) psychological influences. Linear regression was used to assess associations between green space and term birth weight adjusting first for a comprehensive set of confounding factors and then incrementally for pathway variables.ResultsFully adjusted models showed non-statistically significant increases in term birth weight with increasing green space. For example, a 0.1 increase in NDVI within 500 m was associated with a 21.5 g (95% CI − 4.6, 47.7) increase in term birth weight. Associations varied by city and were most robust for high-density locations. For the two largest cities (Vancouver and Toronto), we observed an increase in birth weight of 41.2 g (95% CI 7.8, 74.6) for a 0.1 increase in NDVI within 500 m. We did not observe substantial reductions in the green space effect on birth weight when adjusting for pathway variables.ConclusionOur results highlight the need to further characterize the interactions between green space, urban density and climate related factors as well as the pathways linking residential green space to birth outcomes.

An update on environmental mastitis: Challenging perceptions.

Environmental mastitis is the most common and costly form of mastitis in modern dairy herds where contagious transmission of intramammary pathogens is controlled through implementation of standard mastitis prevention programmes. Environmental mastitis can be caused by a wide range of bacterial species, and binary classification of species as contagious or environmental is misleading, particularly for Staphylococcus aureus, Streptococcus uberis and other streptococcal species, including Streptococcus agalactiae. Bovine faeces, the indoor environment and used pasture are major sources of mastitis pathogens, including Escherichia coli and S.uberis. A faeco-oral transmission cycle may perpetuate and amplify the presence of such pathogens, including Klebsiella pneumoniae and S.agalactiae. Because of societal pressure to reduce reliance on antimicrobials as tools for mastitis control, management of environmental mastitis will increasingly need to be based on prevention. This requires a reduction in environmental exposure through bedding, pasture and pre-milking management and enhancement of the host response to bacterial challenge. Efficacious vaccines are available to reduce the impact of coliform mastitis, but vaccine development for gram-positive mastitis has not progressed beyond the "promising" stage for decades. Improved diagnostic tools to identify causative agents and transmission patterns may contribute to targeted use of antimicrobials and intervention measures. The most important tool for improved uptake of known mastitis prevention measures is communication. Development of better technical or biological tools for management of environmental mastitis must be accompanied by development of appropriate incentives and communication strategies for farmers and veterinarians, who may be confronted with government-mandated antimicrobial use targets if voluntary reduction is not implemented.

Genome-wide association study of blood lead shows multiple associations near ALAD.

Exposure to high levels of environmental lead, or biomarker evidence of high body lead content, is associated with anaemia, developmental and neurological deficits in children, and increased mortality in adults. Adverse effects of lead still occur despite substantial reduction in environmental exposure. There is genetic variation between individuals in blood lead concentration but the polymorphisms contributing to this have not been defined. We measured blood or erythrocyte lead content, and carried out genome-wide association analysis, on population-based cohorts of adult volunteers from Australia and UK (N = 5433). Samples from Australia were collected in two studies, in 1993-1996 and 2002-2005 and from UK in 1991-1992. One locus, at ALAD on chromosome 9, showed consistent association with blood lead across countries and evidence for multiple independent allelic effects. The most significant single nucleotide polymorphism (SNP), rs1805313 (P = 3.91 × 10(-14) for lead concentration in a meta-analysis of all data), is known to have effects on ALAD expression in blood cells but other SNPs affecting ALAD expression did not affect blood lead. Variants at 12 other loci, including ABO, showed suggestive associations (5 × 10(-6) > P > 5 × 10(-8)). Identification of genetic polymorphisms affecting blood lead reinforces the view that genetic factors, as well as environmental ones, are important in determining blood lead levels. The ways in which ALAD variation affects lead uptake or distribution are still to be determined.

Addressing Environmental Contaminants in Pediatric Practice

1. Catherine Karr, MD, MS, PhD* 1. *Assistant Professor of Pediatrics; Director, Pediatric Environmental Health Specialty Unit, University of Washington, Seattle, WA. After completing this article, readers should be able to: 1. Recognize the basis for children's susceptibility to environmental contaminants. 2. Identify common pediatric environmental health problems. 3. Take an environmental history to discern risks. 4. Access reliable and useful resources on pediatric environmental health topics. 5. Discuss environmental exposure reduction and prevention with patients and families. The past decade has been marked by a rapid expansion of scientific inquiry, media reports, and public interest in the topic of environmental contaminants and child health. There are few pediatric environmental health specialists, and most health conditions associated with contaminants in food, water, the home environment, and the community present initially to the primary care clinician. Consequently, pediatricians are increasingly called on to answer questions about environmental health. Although standard medical education on these topics is limited and self-reported confidence among pediatric clinicians is low, extensive knowledge of toxicology is not required to suspect environmental health problems. This article reviews core concepts of pediatric environmental health, commonly encountered pediatric environmental hazards, and the environmental history. Understanding these areas of knowledge should allow the clinician to develop a degree of suspicion that is the foundation for discerning and preventing the potential adverse effects of environmental contaminants in child health. Children's susceptibility to environmental contaminants differs from that of adults. Pediatricians are familiar with the differences inherent in children across the life stages. Therapeutic interventions such as dosing based on weight or surface area is part of everyday practice. Injury prevention advice for a newborn is unique from that given during an adolescent visit. Similar concepts apply to the potential vulnerability of children to adverse consequences of exposure to environmental contaminants, reinforcing …

Novel Approaches forCampylobacterControl in Poultry

The Gram-negative bacterium Campylobacter is the most common bacterial cause of human gastroenteritis in the United States and many industrialized countries. Poultry, particularly chickens, is considered a major source of human campylobacteriosis. Thus, on-farm control of Campylobacter in poultry would reduce the risk of human exposure to this pathogen and have a significant impact on food safety and public health. To date, three general strategies have been proposed to control Campylobacter in poultry at the farm level: (1) reduction of environmental exposure (biosecurity measures), (2) an increase in poultry's host resistance to reduce Campylobacter carriage in the gut (e.g., competitive exclusion, vaccination, and host genetics selection), and (3) the use of antimicrobial alternatives to reduce and even eliminate Campylobacter from colonized chickens (e.g., bacteriophage therapy and bacteriocin treatment). Except for biosecurity measures, the other intervention approaches are currently not commercially available and are still under development. This review is focused on two promising strategies--vaccination and bacteriocin treatment. In particular, we extensively review recent research aimed at discovering and characterizing potent anti-Campylobacter bacteriocins to reduce Campylobacter load at the primary production level in poultry.

Lead Hazards for Pregnant Women and Children

In the United States the risk of lead exposure is far higher among poor, urban, and immigrant populations than among other groups. And even slightly elevated blood lead levels increase children's risk of significant neurobehavioral problems extending through adolescence. Research has shown that blood lead levels in pregnant women well below the Centers for Disease Control and Prevention's "level of concern" of 10 micrograms per deciliter can cause miscarriage, premature birth, low birth weight, and subsequent developmental delays in their children. Despite these well-established dangers of lead exposure, routine prenatal lead screening and education is not a standard of care in the United States. Part 1 of this two-part article (October) presented the case of a pregnant woman with lead poisoning and described the epidemiology of lead exposure in the United States, the main sources of it, and its effects on a pregnant woman and her developing fetus and child. Part 2 describes recommendations for prenatal screening and strategies for dealing with lead exposure when it occurs: education, reduction in environmental exposure, treatment options, and developmental surveillance.

Use of amphotericin B aerosols for the prevention of pulmonary aspergillosis.

Invasive pulmonary Aspergillus infections are increasingly recognized among severely neutropenic and/or immunosuppressed individuals. As the infections are usually acquired through the inhalation of Aspergillus conidia, at present prevention of invasive pulmonary aspergillosis consists mainly of the reduction of environmental exposure to aspergillus conidia. More recently, prophylaxis with amphotericin B aerosols has been investigated. Inhalations with amphotericin B aerosols significantly delayed mortality in an animal model of invasive pulmonary aspergillosis and high pulmonary concentrations of amphotericin B could be achieved. In man, pulmonary deposition of amphotericin B could also be demonstrated using commercially available nebulizers. Inhalations were well tolerated with little systemic absorption of the drug. In order to evaluate the efficacy of aerosol amphotericin B administrations for the prevention of invasive pulmonary aspergillosis, a prospective randomized trial has been initiated.

Evaluation of the Potential Role of Chelation Therapy in Treatment of Low to Moderate Lead Exposures

In the overall long-term management of lead poisoning, chelation therapy can have short-term benefits; however, these benefits must be accompanied by drastic reduction in environmental exposure to lead if therapy is to have any long-term benefit. This discussion is limited to calcium disodium ethylenediaminetetraacetate (CaNa2EDTA), the chelating agent that has been the mainstay of treatment of lead poisoning for the past 38 years, and to meso-2,3-dimercaptosuccinic acid (DMSA), a new and promising oral chelating agent, which is an orphan drug and is currently classified as an investigational new drug by the U.S. Food and Drug Administration. With both drugs, multiple courses of treatment will be needed if any substantial reduction in body lead burden is to be achieved. A major limitation of CaNa2EDTA is the enormous diuresis of zinc that it produces. DMSA produces a comparable diuresis of lead, a greater decrease in blood lead, and has negligible influence on the urinary losses of zinc, copper, iron, and calcium. Limited experience to date in man has revealed no significant adverse side effects of DMSA. In animals, DMSA will promptly reduce the concentration of lead in brain and kidney, in particular. By contrast, similar 5-day courses of CaNa2EDTA do not produce any net reduction in brain lead. This is important, as the brain is the critical organ of the adverse effects of lead in children. If the efficacy of DMSA is to be comprehensively evaluated ethically in children, new and more sensitive neurochemical, electrophysiologic, or other markers must be developed.

Evaluation of the potential role of chelation therapy in treatment of low to moderate lead exposures.

In the overall long-term management of lead poisoning, chelation therapy can have short-term benefits; however, these benefits must be accompanied by drastic reduction in environmental exposure to lead if therapy is to have any long-term benefit. This discussion is limited to calcium disodium ethylenediaminetetraacetate (CaNa2EDTA), the chelating agent that has been the mainstay of treatment of lead poisoning for the past 38 years, and to meso-2,3-dimercaptosuccinic acid (DMSA), a new and promising oral chelating agent, which is an orphan drug and is currently classified as an investigational new drug by the U.S. Food and Drug Administration. With both drugs, multiple courses of treatment will be needed if any substantial reduction in body lead burden is to be achieved. A major limitation of CaNa2EDTA is the enormous diuresis of zinc that it produces. DMSA produces a comparable diuresis of lead, a greater decrease in blood lead, and has negligible influence on the urinary losses of zinc, copper, iron, and calcium. Limited experience to date in man has revealed no significant adverse side effects of DMSA. In animals, DMSA will promptly reduce the concentration of lead in brain and kidney, in particular. By contrast, similar 5-day courses of CaNa2EDTA do not produce any net reduction in brain lead. This is important, as the brain is the critical organ of the adverse effects of lead in children. If the efficacy of DMSA is to be comprehensively evaluated ethically in children, new and more sensitive neurochemical, electrophysiologic, or other markers must be developed.