Environews
Built Environment Tips the Scale toward Obesity
This month's NIEHS News (p. A616) recounts the recent first-ever national conference on obesity and the built environment. Scientists, planners, and policy makers discussed how community design and other elements of the built environment contribute to obesity--and how science and policy together might arrest the epidemic.
Urban Sprawl: The Monster that Ate America
It's big, it's bad, and it's hungry: urban sprawl is gobbling up U.S. lands at an appalling rate, and there's little indication that the monster will be interrupting its meal anytime soon. The Focus (p. A620) investigates the current state of urban sprawl in the United States and tells how a few cities are beginning to fight back against this modern plague.
Skyrocketing Traffic Deaths in Poorer Nations
Traffic deaths in less-affluent nations have been rising steadily over the decades; now a recent World Health Organization (WHO)/World Bank report estimates that if current trends do not change, poorer countries can expect to see an 83% increase in traffic deaths by 2020. Yet, traffic deaths are far from unavoidable. The Spheres of Influence (p. A628) describes the WHO/World Bank report and other recent findings that slowly are awakening policy makers to both the seriousness of this tragic but unnecessary trend as well as the steps necessary to combat it.
Putting Some Fizz in the Future of Foam Plastics
The Innovations (p. A632) tells how clay nanoparticles and supercritical carbon dioxide are being applied to foam plastics to make a material that maintains its desirable properties of light weight, flexibility, cushioning and insulating ability, and enhanced flotation, but without the use of ozone-depleting chlorofluorocarbons.
Research
Are All Estrogens Intrinsically Similar?
Synthetic estrogens released into the environment are often considered to be somehow different from phytoestrogens and physiologic estrogens. Moggs et al. (p. 1137) show gene expression profiling of molecular effects induced by the physiologic estrogen 17ß-estradiol, the phytoestrogen genistein, and the synthetic estrogen diethylstilbestrol in the mouse uterus. Based on evidence that the compounds alter expression of the same 179 genes, the authors conclude that the case has yet to be made for synthetic estrogens presenting a unique human hazard in comparison to phytoestrogens and physiologic estrogens.
Using Disease Outbreaks to Guide Ecosystem Interventions
Human health is often dependent on environmental variables. Cook et al. (p. 1143) argue that, compared to other available measures of ecosystem health, human disease incidence may represent one of the most useful and practical bioindicators for the often elusive gauge of ecologic well-being. Using this approach, appropriate ecologically based strategies for remediation can be introduced at an earlier stage than would be possible when based solely on environmental monitoring, thereby reducing the level of "ecosystem distress" as well as resultant disease burden in humans.
Lead Levels and Minorities in Boston
Lin et al. (p. 1147) measured blood and bone lead levels among minority individuals who live in various neighborhoods in Boston, Massachusetts, with high minority representation. The slopes of the univariate regressions of blood, tibia, and patella lead levels versus age suggested an inflection point at 55 years of age, with slopes for subjects 
55 years of age steeper than those for younger subjects and substantially steeper than those observed in studies of predominantly white participants > 55 years of age. The lead accumulation in this age group is of concern because such levels in other studies predict elevated risks of hypertension and cognitive dysfunction.
Age-Related Differences in Carcinogenesis
In revising cancer risk assessment guidelines, the U. S. Environmental Protection Agency analyzed animal cancer bioassay data over different periods of life. Hattis et al. (p. 1152) report an improved analysis of these data, supplemented with some chemical carcinogenesis observations not included in the original analysis, and animal bioassay studies of ionizing radiation. Central estimate results indicate a 5- to 60-fold increased carcinogenic sensitivity in the birth-weaning period for mutagenic carcinogens and a smaller increase--centered about 5-fold--for radiation carcinogenesis per gray.
Behavioral Alterations by Exposure to BPA and NP
Negishi et al. (p. 1159) examined whether perinatal exposure to bisphenol A (BPA; 0.1 mg/kg/day) and nonylphenol (NP; 0.1 and 10 mg/kg/day) daily from gestational day 3 to postnatal day 20 would, through transplacental and lactational exposures, lead to behavioral alterations in the male offspring of F344 rats. Different behavioral tasks were evaluated in offspring at intervals between 8 and 22 weeks of age. The perinatal low-dose BPA and NP (0.1 mg/kg/day) exposures both irreversibly influenced the reception of fear-provoking stimuli (e.g., electrical shock) as well as monoaminergic neural pathways.
Hair Mercury Levels in Children and Women
Exposure to methyl mercury was assessed in U.S. children 1-5 years of age and women 16-49 years of age using hair mercury analysis during the 1999-2000 National Health and Nutrition Examination Survey. McDowell et al. (p. 1165) report distributions of total hair Hg levels and the association of hair Hg levels with sociodemographic characteristics and fish consumption. Geometric mean hair Hg levels were 0.12 µg/g in children and 0.20 µg/g in women. Geometric mean hair Hg levels among frequent fish consumers were 3-fold higher for women and 2-fold higher for children compared with those of nonconsumers.
Arsenic Mitigation Interventions and Disease Burden in Bangladesh
Many interventions have been advocated to mitigate the impact of arsenic contamination of drinking water in Bangladesh. Lokuge et al. (p. 1172) estimated the likely impacts of arsenic interventions on arsenic-related disease and water-borne infectious disease. Intervention appears to be justified for populations exposed to high levels of arsenic, but it must be based on exposure levels and on the effectiveness of the interventions in reducing arsenic as well as in minimizing the risk of water-related infections. (Also see Science Selections, p. A636)
Lead, Diabetes, Hypertension, and Renal Function
Tsaih et al. (p. 1178) examined changes in renal function over 6 years in relation to baseline lead levels, diabetes, and hypertension in middle-aged and elderly men in a subsample of the Normative Aging Study. Results indicate that longitudinal decline of renal function among middle-aged and elderly individuals appears to be dependent on both long-term lead stores and circulating lead, with an effect that is most pronounced among diabetics and hypertensives, subjects who likely represent particularly susceptible groups. (Also see Science Selections, p. A636)
Pesticide Spraying and Asthma in New York City
Pyrethroid pesticides were applied to residential neighborhoods in New York City during July-September 2000 to control mosquito vectors of West Nile virus (WNV). Some case reports have linked pyrethroid exposure to asthma exacerbations, but population-level effects from large mosquito control programs have not been assessed. Karpati et al. (p. 1183) evaluated whether widespread urban pyrethroid pesticide use was associated with increased rates of emergency department visits for asthma. Following spraying of pyrethroids for WNV control, the authors found no population-level increases in public hospital emergency department visit rates for asthma. (Also see Science Selections, p. A637)
Environmental Medicine
Vinyl Chloride, Hepatocellular Carcinoma, and Cirrhosis
Hepatocellular carcinoma (HCC) and liver cirrhosis (LC) are not well-established vinyl chloride monomer (VCM)-induced diseases. Mastrangelo et al. (p. 1188) evaluated the role of VCM, alcohol intake, and viral hepatitis infection, and their interactions, in the etiology of HCC and LC among cases and controls in a cohort of VCM workers. VCM exposure appears to be an independent risk factor for HCC and LC, interacting synergistically with alcohol consumption and additively with viral hepatitis infection.
PCBs and Pesticides in Human Hair and Blood
Human hair as an exposure measure for persistent organic pollutants has some advantages over blood and adipose tissue samples, but it is limited by difficulty in distinguishing between exogenous and endogenous contamination. Altshul et al. (p. 1193) analyzed hair and blood for select organochlorine pesticides and 57 individual polychlorinated biphenyl (PCB) congeners. There was moderate-to-strong correlation (r = 0.8) between p,p´-DDE levels in hair and blood and moderate correlations for the more persistent PCB congeners, but no correlations or weak correlations for other organochlorines.
Children's Health
Lead Exposure and Bone Density in Children
Osteoporosis is a decrease in bone mineral density (BMD) associated with fractures; a predisposition to osteoporosis may develop during adolescence if sufficient peak BMD is not achieved. Based on rat studies, Campbell et al. (p. 1200) compared BMD of children with high lead exposure with BMD of children with low lead exposure. Contrary to the hypothesis, subjects with high lead exposure had a significantly higher BMD than subjects with low lead exposure. It is possible that lead-influenced accelerated maturation of bone may ultimately result in a lower peak BMD being achieved in young adulthood.
PFOS in Maternal and Cord Blood
Fluorinated organic compounds (FOCs), such as perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorooctane sulfonylamide (PFOSA), are widely distributed. Studies have indicated that FOCs may be detrimental to rodent development by affecting thyroid hormone levels. Inoue et al. (p. 1204) determined the concentrations of FOCs in maternal and cord blood samples among pregnant woman 17-37 years of age. Maternal and fetal PFOS concentrations were highly correlated, but PFOSA was not detected in fetal or maternal samples. There were no significant correlations between PFOS concentrations and age bracket, birth weight, or thyroid-stimulating hormone and free thyroxine levels.
Fetal Exposure to PCBs and Hydroxylated Metabolites
Polychlorinated biphenyls (PCBs) are among the most abundant pollutants, and hydroxy-PCB (OH-PCB) metabolites are formed in both humans and wildlife. Animal studies suggest that these OH-PCBs cause endocrine-related toxicity. Soechitram et al. (p. 1208) measured the levels of PCBs and OH-PCBs in maternal and cord blood samples in a population with background levels of PCBs and found significant correlations between maternal and cord levels for both PCBs and OH-PCBs. Results indicate that OH-PCBs are transferred across the placenta to the fetus at concentrations of approximately 50% of concentrations in maternal plasma.
Trihalomethanes and Fetal Growth
The risk of adverse pregnancy outcomes associated with exposure to drinking-water disinfection by-products remains uncertain. Infante-Rivard (p. 1213) investigated exposure to total and specific trihalomethanes and genetic polymorphisms of CYP2E1 and 5,10-methylenetetrahydrofolate reductase among controls and mothers and newborns diagnosed with uterine growth restriction. Findings suggest that exposure to trihalomethanes at the highest levels can affect fetal growth, but only in genetically susceptible newborns.
[Table of Contents]
Last Updated: July 13, 2004
