Archive

Archive for the ‘Environmental Health Perspectives’ Category

The Societal Costs and Benefits of Commuter Bicycling: Simulating the Effects of Specific Policies Using System Dynamics Modeling

July 14, 2014 Comments off

The Societal Costs and Benefits of Commuter Bicycling: Simulating the Effects of Specific Policies Using System Dynamics Modeling
Source: Environmental Health Perspectives

Background:
Shifting to active modes of transport in the trip to work can achieve substantial co-benefits for health, social equity, and climate change mitigation. Previous integrated modeling of transport scenarios has assumed active transport mode share and has been unable to incorporate acknowledged system feedbacks.

Objectives:
We compared the effects of policies to increase bicycle commuting in a car-dominated city and explored the role of participatory modeling to support transport planning in the face of complexity.

Methods:
We used system dynamics modeling (SDM) to compare realistic policies, incorporating feedback effects, nonlinear relationships, and time delays between variables. We developed a system dynamics model of commuter bicycling through interviews and workshops with policy, community, and academic stakeholders. We incorporated best available evidence to simulate five policy scenarios over the next 40 years in Auckland, New Zealand. Injury, physical activity, fuel costs, air pollution, and carbon emissions outcomes were simulated.

Results:
Using the simulation model, we demonstrated the kinds of policies that would likely be needed to change a historical pattern of decline in cycling into a pattern of growth that would meet policy goals. Our model projections suggest that transforming urban roads over the next 40 years, using best practice physical separation on main roads and bicycle-friendly speed reduction on local streets, would yield benefits 10–25 times greater than costs.

Conclusions:
To our knowledge, this is the first integrated simulation model of future specific bicycling policies. Our projections provide practical evidence that may be used by health and transport policy makers to optimize the benefits of transport bicycling while minimizing negative consequences in a cost-effective manner. The modeling process enhanced understanding by a range of stakeholders of cycling as a complex system. Participatory SDM can be a helpful method for integrating health and environmental outcomes in transport and urban planning.

About these ads

Outdoor Particulate Matter Exposure and Lung Cancer: A Systematic Review and Meta-Analysis

July 14, 2014 Comments off

Outdoor Particulate Matter Exposure and Lung Cancer: A Systematic Review and Meta-Analysis
Source: Environmental Health Perspectives

Background:
Particulate matter (PM) in outdoor air pollution was recently designated a Group I carcinogen by the International Agency for Research on Cancer (IARC). This determination was based on the evidence regarding the relationship of PM2.5 and PM10 to lung cancer risk; however, the IARC evaluation did not include a quantitative summary of the evidence.

Objective:
To provide a systematic review and quantitative summary of the evidence regarding the relationship between PM and lung cancer.

Methods:
We conducted meta-analyses of studies examining the relationship of exposure to PM2.5 and PM10 with lung cancer incidence and mortality. In total, 18 studies met inclusion criteria and provided the information necessary to estimate the change in lung cancer risk per 10-μg/m3 increase in exposure to PM. We used random effects analyses to allow between study variability to contribute to meta-estimates.

Results:
The meta-relative risk (95% CI) for lung cancer associated with PM2.5 was 1.09 (95% CI: 1.04, 1.14). The meta-relative risk of lung cancer associated with PM10 was similar, but less precise: 1.08 (95% CI: 1.00, 1.17). Estimates were robust to restriction to studies that considered potential confounders, as well as sub-analyses by exposure assessment method. Analyses by smoking status showed that lung cancer risk associated with PM2.5 was greatest for former smokers, 1.44 (95% CI: 1.04, 1.22) followed by never smokers, 1.18 (95% CI: 1.00, 1.39), and then current smokers, 1.06 (95% CI: 0.97, 1.15). In addition, meta-estimates for adenocarcinoma associated with PM2.5 and PM10 were 1.40 (95% CI: 1.07, 1.83) and 1.29 (95% CI: 1.02, 1.63), respectively.

Conclusion:
The results of these analyses, and the decision of the IARC working group to classify PM and outdoor air pollution as carcinogenic (Group 1), further justify efforts to reduce exposures to air pollutants that can arise from many sources.

Summertime Acute Heat Illness in U.S. Emergency Departments from 2006 through 2010: Analysis of a Nationally Representative Sample

July 10, 2014 Comments off

Summertime Acute Heat Illness in U.S. Emergency Departments from 2006 through 2010: Analysis of a Nationally Representative Sample
Source: Environmental Health Perspectives

Background:
Patients with acute heat illness present primarily to emergency departments (EDs), yet little is known regarding these visits.

Objective:
To describe acute heat illness visits to US EDs from 2006-2010 and identify factors associated with hospital admission or death-in-the-ED.

Methods:
We extracted ED case-level data from the Nationwide Emergency Department Sample (NEDS) for 2006-10, defining cases as ED visits from May-September with any heat illness diagnosis (ICD-9-CM 992.0-992.9). We correlated visit rates and temperature anomalies analyzed demographics and ED disposition, identified risk factors for adverse outcomes, and examined ED case fatality rates (CFR).

Results:
There were 326,497 (95% CI: 308,372-344,658) cases, with 287,875 (88.2%) treated-and-released, 38,392 (11.8%) admitted, and 230 (0.07%) died-in-the-ED. Heat illness diagnoses were first-listed in 68%. 74.7% had heat exhaustion, 5.4% heat stroke. Visit rates were highly correlated with annual temperature anomalies (correlation coefficient 0.90, p=0.037). Treat-and-release rates were highest for younger adults (26.2/100,000/year), while hospitalization and death-in-the-ED rates were highest for older adults (6.7 and 0.03/100,000/year respectively); all rates were highest in rural areas. Heat stroke had an ED CFR of 99.4/10,000 (78.7-120.1) visits and was diagnosed in 77.0% of deaths. Adjusted odds of hospital admission or death-in-the-ED were higher among elders, males, urban and low income residents, and those with chronic conditions.

Conclusions:
Heat illness presented to the ED frequently, with highest rates in rural areas. Case definitions should include all diagnoses. Visit rates were correlated with temperature anomalies. Heat stroke had a high ED CFR. Males, elders, and the chronically ill were at greatest risk of admission or death-in-the-ED. Chronic disease burden exponentially increased this risk.

Daily Mean Temperature and Clinical Kidney Stone Presentation in Five U.S. Metropolitan Areas: A Time-Series Analysis

July 10, 2014 Comments off

Daily Mean Temperature and Clinical Kidney Stone Presentation in Five U.S. Metropolitan Areas: A Time-Series Analysis
Source: Environmental Health Perspectives

Background:
High ambient temperatures are a risk factor for nephrolithiasis, but the precise relationship between temperature and kidney stone presentation is unknown.

Objectives:
Our objective was to estimate associations between mean daily temperature and kidney stone presentation according to lag time and temperatures.

Methods:
Using a time series design and distributed lag non-linear models, we estimated the relative risk (RR) of kidney stone presentation associated with mean daily temperatures, including cumulative RR for a 20-day period, and RR for individual daily lags through 20 days. Our analysis used MarketScan data for 60,433 patients who presented for evaluation or treatment of kidney stones from 2005–2011 in Atlanta, Chicago, Dallas, Los Angeles, and Philadelphia.

Results:
Associations between mean daily temperature and kidney stone presentation were not monotonic, and there was variation in the exposure-response curve shapes and the strength of associations at different temperatures. However, in most cases RRs increased for temperatures above the reference value of 10°C. The cumulative RR for a daily mean temperature of 30°C versus 10°C was 1.38 in Atlanta (95% CI: 1.07, 1.79), 1.37 in Chicago (95% CI: 1.07, 1.76), 1.36 in Dallas (95% CI: 1.10, 1.69), 1.11 in Los Angeles (95% CI: 0.73, 1.68), and 1.47 in Philadelphia (95% CI: 1.00, 2.17). Kidney stone presentations also were positively associated with temperatures < 2°C in Atlanta, and < 10°C in Chicago and Philadelphia. In 4 cities, the strongest association between kidney stone presentation and a daily mean temperature of 30 versus 10°C was estimated for lags ≤ 3 days.

Conclusions:
In general, kidney stone presentations increased with higher daily mean temperatures, with the strongest associations estimated for lags of only a few days. These findings further support an adverse effect of high temperatures on nephrolithiasis.

Take Care in the Kitchen: Avoiding Cooking-Related Pollutants

June 25, 2014 Comments off

Take Care in the Kitchen: Avoiding Cooking-Related Pollutants
Source: Environmental Health Perspectives

Carbon monoxide (CO), nitrogen dioxide (NO2), and particulate matter (PM) are harmful air pollutants that pose significant short- and long-term health risks. Emitted from coal-fired power plants, vehicle exhaust pipes, and other combustion sources, they’re among six primary pollutants monitored by the U.S. Environmental Protection Agency (EPA) through the Clean Air Act. These same pollutants are also some of the most common contributors to unhealthy air inside U.S. homes, due in part to a ubiquitous and possibly surprising activity: cooking.

Researchers now understand that the process of cooking food and even simply operating stoves—particularly gas appliances—can emit a cocktail of potentially hazardous chemicals and compounds. Within our homes, these pollutants are less diluted than they are outdoors, and in the absence of proper ventilation, they often are trapped inside. The World Health Organization has established general guidelines for indoor air quality and is currently developing specific limits related to burning solid fuels for cooking and heating. However, indoor air in nonindustrial buildings is not regulated by the EPA or any other U.S. agency.

Neurodevelopmental Disorders and Prenatal Residential Proximity to Agricultural Pesticides: The CHARGE Study

June 24, 2014 Comments off

Neurodevelopmental Disorders and Prenatal Residential Proximity to Agricultural Pesticides: The CHARGE Study
Source: Environmental Health Perspectives

Background:
Gestational exposure to several common agricultural pesticides can induce developmental neurotoxicity in humans, and has been associated with developmental delay and autism.

Objectives:
To evaluate whether residential proximity to agricultural pesticides during pregnancy is associated with autism spectrum disorders (ASD) or developmental delay (DD) in the Childhood Autism Risks from Genetics and Environment (CHARGE) Study.

Methods:
The CHARGE study is a population-based case-control study of ASD, developmental delay (DD), and typical development. For 970 participants, commercial pesticide application data from the California Pesticide Use Report (1997-2008) were linked to the addresses during pregnancy. Pounds of active ingredient applied for organophophates, organochlorines, pyrethroids, and carbamates were aggregated within 1.25km, 1.5km, and 1.75km buffer distances from the home. Multinomial logistic regression was used to estimate the odds ratio (OR) of exposure comparing confirmed cases of ASD (n = 486) or DD (n = 168) with typically developing referents (n = 316).

Results:
Approximately one-third of CHARGE Study mothers lived, during pregnancy, within 1.5 km (just under one mile) of an agricultural pesticide application. Proximity to organophosphates at some point during gestation was associated with a 60% increased risk for ASD, higher for 3rd trimester exposures [OR = 2.0, 95% confidence interval (CI) = (1.1, 3.6)], and 2nd trimester chlorpyrifos applications: OR = 3.3 [95% CI = (1.5, 7.4)]. Children of mothers residing near pyrethroid insecticide applications just prior to conception or during 3rd trimester were at greater risk for both ASD and DD, with OR’s ranging from 1.7 to 2.3. Risk for DD was increased in those near carbamate applications, but no specific vulnerable period was identified.

Conclusions:
This study of ASD strengthens the evidence linking neurodevelopmental disorders with gestational pesticide exposures, and particularly, organophosphates and provides novel results of ASD and DD associations with, respectively, pyrethroids and carbamates.

Environmental Noise Pollution in the United States: Developing an Effective Public Health Response

March 7, 2014 Comments off

Environmental Noise Pollution in the United States: Developing an Effective Public Health Response (PDF)
Source: Environmental Health Perspectives

Background:
Tens of millions of Americans suffer from a range of adverse health outcomes due to noise exposure, including heart disease and hearing loss. Reducing environmental noise pollution is achievable and consistent with national prevention goals, yet there is no national plan to reduce environmental noise pollution.

Objectives:
We aimed to describe some of the most serious health effects associated with noise, summarize exposures from several highly prevalent noise sources based on published estimates as well as extrapolations made using these estimates, and lay out proven mechanisms and strategies to reduce noise by incorporating scientific insight and technological innovations into existing public health infrastructure.

Discussion:
We estimated that 104 million individuals had annual LEQ(24) levels > 70 dBA (equivalent to a continuous average exposure level of >70 dBA over 24 hr) in 2013 and were at risk of noise-induced hearing loss. Tens of millions more may be at risk of heart disease, and other noise-related health effects. Direct regulation, altering the informational environment, and altering the built environment are the least costly, most logistically feasible, and most effective noise reduction interventions.

Conclusion:
Significant public health benefit can be achieved by integrating interventions that reduce environmental noise levels and exposures into the federal public health agenda.

Birth Outcomes and Maternal Residential Proximity to Natural Gas Development in Rural Colorado

February 6, 2014 Comments off

Birth Outcomes and Maternal Residential Proximity to Natural Gas Development in Rural Colorado
Source: Environmental Health Perspectives

Background:
Birth defects are a leading cause of neonatal mortality. Natural gas development (NGD) emits several potential teratogens and US production is expanding.

Objectives:
We examined associations between maternal residential proximity to NGD and birth outcomes in a retrospective cohort study of 124,842 births between 1996 and 2009 in rural Colorado.

Methods:
We calculated inverse distance weighted natural gas well counts within a 10-mile radius of maternal residence to estimate maternal exposure to NGD. Logistic regression, adjusted for maternal and infant covariates, was used to estimate associations with exposure tertiles for congenital heart defects (CHDs), neural tube defects (NTDs), oral clefts, preterm birth, and term low birth weight. The Association with term birth weight was investigated using multiple linear regression.

Results:
Prevalence of CHDs increased with exposure tertile, with an odds ratio (OR) of 1.3 for the highest tertile (95% CI: 1.2, 1.5) and NTD prevalence was associated with the highest tertile of exposure (OR = 2.0, 95% CI: 1.0, 3.9, based on 59 cases), compared to no gas wells within a 10-mile radius. Exposure was negatively associated with preterm birth and positively associated with fetal growth, though the magnitude of association was small. No association was found between exposure and oral clefts.

Conclusions:
In this large cohort, we observed an association between density and proximity of natural gas wells within a 10-mile radius of maternal residence and prevalence of CHDs and possibly NTDs. Greater specificity in exposure estimates are needed to further explore these associations.

See: Study Finds Increased Risk of Children with Heart Disease Born Near Natural Gas Drilling (AllGov.com)

Concentrations and Potential Health Risks of Metals in Lip Products

August 19, 2013 Comments off

Concentrations and Potential Health Risks of Metals in Lip Products
Source: Environmental Health Perspectives

Background:
Metal content in lip products has been an issue of concern.

Objectives:
We measured lead and eight other metals in a convenience sample of 32 lip products used by young Asian women in Oakland, California, and assessed potential health risks related to estimated intakes of these metals.

Methods:
We analyzed lip products by inductively coupled plasma optical emission spectrometry and used previous estimates of lip product usage rates to determine daily oral intakes. We derived acceptable daily intakes (ADIs) based on information used to determine public health goals for exposure, and compared ADIs with estimated intakes to assess potential risks.

Results:
Most of the tested lip products contained high concentrations of titanium and aluminum. All examined products had detectable manganese. Lead was detected in 24 products (75%), with an average concentration of 0.36 ± 0.39 ppm, including one sample with 1.32 ppm. When used at the estimated average daily rate, estimated intakes were > 20% of ADIs derived for aluminum, cadmium, chromium, and manganese. In addition, average daily use of 10 products tested would result in chromium intake exceeding our estimated ADI for chromium. For high rates of product use (above the 95th percentile), the percentages of samples with estimated metal intakes exceeding ADIs were 3% for aluminum, 68% for chromium, and 22% for manganese. Estimated intakes of lead were < 20% of ADIs for average and high use.

Conclusions:
Cosmetics safety should be assessed not only by the presence of hazardous contents, but also by comparing estimated exposures with health-based standards. In addition to lead, metals such as aluminum, cadmium, chromium, and manganese require further investigation.

The Racial/Ethnic Distribution of Heat Risk-Related Land Cover in Relation to Residential Segregation

May 15, 2013 Comments off

The Racial/Ethnic Distribution of Heat Risk-Related Land Cover in Relation to Residential Segregation

Source: Environmental Health Perspectives

Objective: To examine the distribution of heat risk-related land cover (HRRLC) characteristics across racial/ethnic groups and degrees of residential segregation.

Methods: Block group-level tree canopy and impervious surface estimates were derived from the 2001 National Land Cover Dataset for densely populated urban areas of the United States and Puerto Rico, and linked to demographic characteristics from the 2000 Census. Racial/ethnic groups in a given block group were considered to live in HRRLC if at least half their population experienced the absence of tree canopy and at least half of the ground covered by impervious surface (roofs, driveways, sidewalks, roads). Residential segregation was characterized for metropolitan areas in the United States and Puerto Rico using the multigroup dissimilarity index.

Results: After adjusting for ecoregion and precipitation, and holding segregation level constant, non-Hispanic blacks were 52% more likely (95% confidence interval (CI): 37% to 69%), non-Hispanic Asians 32% more likely (95% CI: 18% to 47%), and Hispanics 21% more likely (95% CI: 8% to 35%) to live in HRRLC conditions compared to non-Hispanic whites. Within each racial/ethnic group, HRRLC conditions increased with increasing degrees of metropolitan area-level segregation. Further adjustment for home ownership and poverty did not substantially alter these results, but adjustment for population density and metropolitan area population attenuated the segregation effects, suggesting a mediating or confounding role.

Conclusions: Land cover was associated with segregation within each racial/ethnic group, which may be partially explained by the concentration of racial/ethnic minorities into densely populated neighborhoods within larger, more segregated cities. In anticipation of greater frequency and duration of extreme heat events, climate change adaptation strategies, such as planting trees in urban areas, should explicitly incorporate an environmental justice framework that addresses racial/ethnic disparities in HRRLC.

See: Racial minorities live on the front lines of heat risk, study finds (EurekAlert!)

Roxarsone, Inorganic Arsenic, and Other Arsenic Species in Chicken: A U.S.-Based Market Basket Sample

May 13, 2013 Comments off

Roxarsone, Inorganic Arsenic, and Other Arsenic Species in Chicken: A U.S.-Based Market Basket Sample

Source: Environmental Health Perspectives

Background: Arsenic-based drugs are permitted in poultry production. Inorganic arsenic (iAs) causes cancer and maybe other adverse health outcomes. The contribution of chicken consumption to iAs intake, however, is unknown.

Objectives: To characterize arsenic species profile in chicken meat and estimate bladder and lung cancer risk associated with consuming chicken produced with arsenic-based drugs.

Methods: Conventional, conventional antibiotic-free, and organic chicken samples were collected from grocery stores in ten US metropolitan areas from December 2010 to June 2011. 116 raw and 142 cooked samples were tested for total arsenic, and 78 samples ≥10µg/kg dry weight underwent speciation.

Results: Total arsenic geometric mean (GM) in cooked chicken meat samples was 3.0 µg/kg (95% CI: 2.5, 3.6). Among 78 cooked samples that were speciated, iAs concentrations were higher in conventional samples (GM = 1.8 µg/kg; 95% CI: 1.4, 2.3) than antibiotic-free (GM = 0.7 µg/kg; 95% CI: 0.5, 1.0) or organic (GM = 0.6 µg/kg; 95% CI: 0.5, 0.8) samples. Roxarsone was detected in 20 of 40 conventional samples, one of 13 antibiotic-free samples, and none of the 25 organic samples. iAs concentrations in roxarsone-positive samples (GM = 2.3 µg/kg; 95% CI: 1.7, 3.1) were significantly higher than in roxarsone-negative samples (GM = 0.8 µg/kg; 95% CI: 0.7, 1.0). Cooking increased iAs and decreased roxarsone concentrations. Compared to organic chicken consumers, we estimated that conventional chicken consumers would ingest an additional 0.11µg/day iAs (in an 82g serving). Assuming lifetime exposure and a proposed cancer slope factor of 25.7 (mg kgBW-1 day-1)-1, this could result in 3.7 extra lifetime bladder and lung cancer cases per 100,000 exposed-persons.

Conclusions: Conventional chicken meat had higher iAs concentrations than conventional antibiotic-free and organic chicken meat samples. Cessation of arsenical drug use could reduce exposure and the burden of arsenic-related disease in chicken consumers.

Concentrations and Potential Health Risks of Metals in Lip Products

May 8, 2013 Comments off

Concentrations and Potential Health Risks of Metals in Lip Products

Source: Environmental Health Perspectives

Background:
Metal content in lip products has been an issue of concern.

Objectives:
We measured lead and eight other metals in a convenience sample of 32 lip products used by young Asian women in Oakland, California, USA, and assessed potential health risks related to estimated intakes of these metals.

Methods:
We analyzed lip products by inductively coupled plasma optical emission spectrometry and used previous estimates of lip product usage rates to determine daily oral intakes. We derived acceptable daily intakes (ADIs) based on information used to determine public health goals for exposure, and compared ADIs with estimated intakes to assess potential risks.

Results:
Most of the tested lip products contained high concentrations of titanium and aluminum. All examined products had detectable manganese. Lead was detected in 24 products (75%) with an average concentration of 0.36 ppm ± 0.39, including one sample with 1.32 ppm. When used at the estimated average daily rate, estimated intakes were >20% of ADIs derived for aluminum, cadmium, chromium and manganese. In addition, average daily use of 10 products tested would result in chromium intake exceeding our estimated ADI for chromium. For high rates of product use (above the 95th percentile) the percentages of samples with estimated metal intakes exceeding ADIs were 3% for aluminum, 68% for chromium, and 22% for manganese. Estimated intakes of lead were < 20% of ADIs for average and high use.

Conclusions:
Cosmetics safety should be assessed not only by the presence of hazardous contents, but also by comparing estimated exposures with health based standards. In addition to lead, metals such as aluminum, cadmium, chromium and manganese require further investigation.

Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis

February 12, 2013 Comments off

Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis
Source: Environmental Health Perspectives

Background:
Although fluoride may cause neurotoxicity in animal models and acute fluoride poisoning causes neurotoxicity in adults, very little is known of its effects on children’s neurodevelopment.

Objective:
We performed a systematic review and meta-analysis of published studies to investigate the effects of increased fluoride exposure and delayed neurobehavioral development.

Methods:
We searched the MEDLINE, EMBASE, Water Resources Abstracts, and TOXNET databases through 2011 for eligible studies. We also searched the China National Knowledge Infrastructure (CNKI) database, because many studies on fluoride neurotoxicity have been published in Chinese journals only. In total, we identified 27 eligible epidemiological studies with high and reference exposures, end points of IQ scores, or related cognitive function measures with means and variances for the two exposure groups. Using random-effects models, we estimated the standardized mean difference between exposed and reference groups across all studies. We conducted sensitivity analyses restricted to studies using the same outcome assessment and having drinking-water fluoride as the only exposure. We performed the Cochran test for heterogeneity between studies, Begg’s funnel plot, and Egger test to assess publication bias, and conducted meta-regressions to explore sources of variation in mean differences among the studies.

Results:
The standardized weighted mean difference in IQ score between exposed and reference populations was –0.45 (95% confidence interval: –0.56, –0.35) using a random-effects model. Thus, children in high-fluoride areas had significantly lower IQ scores than those who lived in low-fluoride areas. Subgroup and sensitivity analyses also indicated inverse associations, although the substantial heterogeneity did not appear to decrease.

Conclusions:
The results support the possibility of an adverse effect of high fluoride exposure on children’s neurodevelopment. Future research should include detailed individual-level information on prenatal exposure, neurobehavioral performance, and covariates for adjustment.

Radiation and the Risk of Chronic Lymphocytic and Other Leukemias among Chornobyl Cleanup Workers

November 15, 2012 Comments off

Radiation and the Risk of Chronic Lymphocytic and Other Leukemias among Chornobyl Cleanup Workers

Source: Environmental Health Perspectives

Background: Risks of most types of leukemia from exposure to acute high doses of ionizing radiation are well known, but risks associated with protracted exposures, and associations between radiation and chronic lymphocytic leukemia (CLL) are not clear.

Objectives: To estimate relative risks of CLL and non-CLL from protracted exposures to low-dose ionizing radiation.

Methods: A nested case-control study was conducted in a cohort of 110,645 Ukrainian cleanup workers of the 1986 Chornobyl nuclear power plant accident. Cases of incident leukemia diagnosed in 1986-2006 were confirmed by a panel of expert hematologists/hematopathologists. Controls were matched to cases on place of residence and year of birth. Individual bone marrow radiation doses were estimated by the Realistic Analytical Dose Reconstruction with Uncertainty Estimation (RADRUE) method. A conditional logistic regression model was used to estimate excess relative risk of leukemia per gray (ERR/Gy) of radiation dose.

Results:A significant linear dose-response was found for all leukemia (137 cases, ERR/Gy=1.26 (95% confidence interval 0.03, 3.58)). There were non-significant positive dose-responses for both CLL and non-CLL (ERR/Gy=0.76 and 1.87, respectively). In our primary analysis excluding 20 cases with direct in-person interviews

Conclusions: Exposure to low doses and low dose-rates of radiation from post-Chornobyl cleanup work was associated with a significant increase in risk of leukemia, which was statistically consistent with estimates for the Japanese atomic bomb survivors. Based on the primary analysis, we conclude that CLL and non-CLL are both radiosensitive.

See: Chernobyl Cleanup Workers Had Significantly Increased Risk of Leukemiahttp://www.sciencedaily.com/releases/2012/11/121108073635.htm (Science Daily)

Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis

November 9, 2012 Comments off

Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis

Source: Environmental Health Perspectives

Background: Although fluoride may cause neurotoxicity in animal models and acute fluoride poisoning causes neurotoxicity in adults, very little is known of its effects on children’s neurodevelopment.

Objective: We performed a systematic review and meta-analysis of published studies to investigate the effects of increased fluoride exposure and delayed neurobehavioral development.

Methods: We searched the MEDLINE, EMBASE, Water Resources Abstracts, and TOXNET databases through 2011 for eligible studies. We also searched the China National Knowledge Infrastructure (CNKI) database, because many studies on fluoride neurotoxicity have been published in Chinese journals only. In total, we identified 27 eligible epidemiological studies with high and reference exposures, end points of IQ scores, or related cognitive function measures with means and variances for the two exposure groups. Using random-effects models, we estimated the standardized mean difference between exposed and reference groups across all studies. We conducted sensitivity analyses restricted to studies using the same outcome assessment and having drinking-water fluoride as the only exposure. We performed the Cochran test for heterogeneity between studies, Begg’s funnel plot, and Egger test to assess publication bias, and conducted meta-regressions to explore sources of variation in mean differences among the studies.

Results: The standardized weighted mean difference in IQ score between exposed and reference populations was –0.45 (95% confidence interval: –0.56, –0.35) using a random-effects model. Thus, children in high-fluoride areas had significantly lower IQ scores than those who lived in low-fluoride areas. Subgroup and sensitivity analyses also indicated inverse associations, although the substantial heterogeneity did not appear to decrease.

Conclusions: The results support the possibility of an adverse effect of high fluoride exposure on children’s neurodevelopment. Future research should include detailed individual-level information on prenatal exposure, neurobehavioral performance, and covariates for adjustment.

Bisphenol A and Peripheral Arterial Disease: Results from the NHANES

September 28, 2012 Comments off

Bisphenol A and Peripheral Arterial Disease: Results from the NHANES
Source: Environmental Health Perspectives

Background: Bisphenol A (BPA) is a common chemical used in the manufacture of polycarbonate
plastics and epoxy resins, and > 93% of U.S. adults have detectable levels of urinary BPA. Recent animal studies have suggested that BPA exposure may have a role in several mechanisms involved in the development of cardiovascular disease (CVD), including weight gain, insulin resistance, thyroid dysfunction, endothelial dysfunction, and oxidative stress. However, few human studies have examined
the association between markers of BPA exposure and CVD. Peripheral arterial disease (PAD) is a subclinical measure of atherosclerotic vascular disease and a strong independent risk factor for CVD and mortality.

Objective: We examined the association between urinary BPA levels and PAD in a nationally representative sample of U.S. adults.

Methods: We analyzed data from 745 participants in the National Health and Nutritional Examination Survey 2003–2004. We estimated associations between urinary BPA levels (in tertiles) and PAD (ankle–brachial index < 0.9, n = 63) using logistic regression models adjusted for potentialconfounders (age, sex, race/ethnicity, education, smoking, body mass index, diabetes mellitus, hypertension, urinary creatinine, estimated glomerular filtration rate, and serum cholesterol levels).

Results: We observed a significant, positive association between increasing levels of urinary BPA and PAD before and after adjusting for confounders. The multivariable-adjusted odds ratio for PAD associated with the highest versus lowest tertile of urinary BPA was 2.69 (95% confidence interval: 1.02, 7.09; p-trend = 0.01).

Conclusions: Urinary BPA levels were significantly associated with PAD, independent of traditional CVD risk factors.

Near-Roadway Pollution and Childhood Asthma: Implications for Developing “Win-Win” Compact Urban Development and Clean Vehicle Strategies

September 25, 2012 Comments off

Near-Roadway Pollution and Childhood Asthma: Implications for Developing “Win-Win” Compact Urban Development and Clean Vehicle Strategies

Source: Environmental Health Perspectives

Background: The emerging consensus that exposure to near-roadway traffic-related pollution causes asthma has implications for compact urban development policies designed to reduce driving and greenhouse gases.

Objectives: We estimated the current burden of childhood asthma-related disease attributable to near-roadway and regional air pollution in Los Angeles County (LAC) and the potential health impact of regional pollution reduction associated with changes in population along major traffic corridors.

Methods: The burden of asthma attributable to the dual effects of near-roadway and regional air pollution was estimated, using nitrogen dioxide and ozone as markers of urban combustion-related and secondary oxidant pollution, respectively. We also estimated the impact of alternative scenarios that assumed a 20% reduction in regional pollution in combination with a 3.6% reduction or 3.6% increase in the proportion of the total population living near major roads, a proxy for near-roadway exposure.

Results: We estimated that 27,100 cases of childhood asthma (8% of total) in LAC were at

least partly attributable to pollution associated with residential location within 75m of a major

road. As a result, a substantial proportion of asthma-related morbidity is a consequence of nearroadway

pollution, even if symptoms are triggered by other factors. Benefits resulting from a

20% regional pollution reduction varied markedly depending on the associated change in nearroadway

proximity.

Conclusions: Our findings suggest that there are large and previously unappreciated public health consequences of air pollution in LAC and probably in other metropolitan areas with dense traffic corridors. To maximize health benefits, compact urban development strategies should be coupled with policies to reduce near-roadway pollution exposure.

Environmental Inequality in Exposures to Airborne Particulate Matter Components in the United States

August 22, 2012 Comments off

Environmental Inequality in Exposures to Airborne Particulate Matter Components in the United States
Source: Environmental Health Perspective

Background:
Growing evidence indicates that toxicity of fine particles (PM2.5) differs by chemical component. Exposure to components may differ by population.

Objectives:
We investigated whether exposures to PM2.5 components differ by race/ethnicity, age, and socio-economic status (SES).

Methods:
Long-term exposures (2000-2006) were estimated for 215 US census tracts for PM2.5 and 14 PM2.5 components. Population-weighted exposures were combined to generate overall estimated exposures by race/ethnicity, education, poverty status, employment, age, and earnings. Population characteristics for tracts with and without PM2.5 component monitors were compared.

Results:
Larger disparities in estimated exposures were observed for components than for PM2.5 total mass. For race/ethnicity, whites generally had the lowest exposures. Non-Hispanic blacks had higher exposures than whites for 13 of the 14 components. Hispanics generally had the highest exposures (e.g., 152% higher than whites for chlorine, 94% higher for aluminum). Young persons (0-19yrs) had levels as high as or higher than other ages for all exposures except sulfate. Persons with lower SES had higher estimated exposures, with some exceptions. For example, a 10% increase in the proportion unemployed was associated with a 20.0% increase in vanadium and an 18.3% increase in elemental carbon. Census tracts with monitors had more non-Hispanic blacks, lower education and earnings, and higher unemployment and poverty than tracts without monitors.

Conclusions:
Exposures to PM2.5 components differed by race/ethnicity, age, and SES. If some components are more toxic than others, certain populations are likely to suffer higher health burdens. Demographics differed between populations covered and not covered by monitors.

Health Benefits From Large Scale Ozone Reduction in the United States

July 26, 2012 Comments off

Health Benefits From Large Scale Ozone Reduction in the United States

Source: Environmental Health Perspectives

Background:

Exposure to ozone has been associated with adverse health effects, including premature mortality, cardiopulmonary and respiratory morbidity. In 2008, the U.S. Environmental Protection Agency (EPA) lowered the primary (health-based) National Ambient Air Quality Standard (NAAQS) for ozone to 75ppb, expressed as the fourth-highest daily maximum 8-hr average over a 24-hr period. Based on recent monitoring data, U.S. ozone levels still exceed this standard in numerous locations resulting in avoidable adverse health consequences.

Objectives:

To quantify the potential human health benefits from achieving the current primary NAAQS standard of 75ppb and two alternative standard levels, 70 and 60ppb, representing the range recommended by the EPA Clean Air Scientific Advisory Committee (CASAC).

Methods:

We apply health impact assessment methodology to estimate numbers of deaths and other adverse health outcomes that would have been avoided during 2005, 2006 and 2007 if the current NAAQS ozone standards (or lower standards) had been met. Estimated reductions in ozone concentrations were interpolated according to geographic area and year, and concentration-response functions were obtained or derived from the epidemiological literature.

Results:

We estimated that annual numbers of avoided ozone-related premature deaths would have ranged from 1,410-2,480 at 75ppb to 2,450-4,130 at 70ppb and 5,210-7,990 at 60ppb. Acute respiratory symptoms would have been reduced by 3 million cases and school-loss days by one million cases annually if the current 75ppb standard had been attained. Substantially greater health benefits would have resulted if the CASAC recommended range of standards (70 to 60ppb) had been met.

Conclusions:

Attaining a more stringent primary ozone standard would significantly reduce ozone-related premature mortality and morbidity.

A Sensitive Approach to Studying ASDs: Teasing Out Relationships between Autism and Maternal Smoking

July 8, 2012 Comments off

A Sensitive Approach to Studying ASDs: Teasing Out Relationships between Autism and Maternal Smoking
Source: Environmental Health Perspectives

Both genetic and environmental factors have been implicated in autism spectrum disorders (ASDs), which affect an estimated 1 in 88 children. One such environmental factor, prenatal exposure to tobacco smoke via maternal smoking, has been associated with ASDs in some studies but not others. A new study reports evidence of a positive association between maternal smoking during pregnancy and higher-functioning ASD subtypes [EHP 120(7):1042–1048; Kalkbrenner et al.].

The authors collected information on maternal smoking and other factors from the birth certificates for 633,989 children born in 1992, 1994, 1996, and 1998 in 11 U.S. states. They linked these data with surveillance data from the U.S. Centers for Disease Control and Prevention’s Autism and Developmental Disabilities Monitoring network and identified 3,315 of the children who were subsequently diagnosed with an ASD by age 8 years.

About 13% of all the mothers smoked during pregnancy, compared with about 11% of mothers with children diagnosed with an ASD. Maternal smoking has been associated with both lower education and reduced access to health care, factors that might increase the likelihood that ASDs go undiagnosed among children of women who smoked during pregnancy. When the authors corrected for this potential bias using outcome misclassification sensitivity analyses, a weak positive association emerged between maternal smoking and cases classified as “ASD not otherwise specified,” which were assumed to be higher-functioning ASDs such as Asperger’s disorder. The association was not found for lower-functioning (that is, more severe) ASDs.

The authors write that their findings concerning ASD subgroups should be interpreted with caution because the accuracy of subgroup classification may have varied depending upon mothers’ access to evaluation services, and because it was not bas ed on direct clinical observation. They also note that positive associations may reflect the presence in higher-functioning subgroups of children with co-occurring disorders (such as attention deficit/hyperactivity disorder) that can be affected by nicotine exposure.

Strengths of the study include the large sample size, the population-based design with standardized identification of ASD cases, and the use of sensitivity analyses to evaluate potential sources of bias. The authors conclude that the observed association between maternal smoking during pregnancy and higher-functioning ASDs warrants further research.

Follow

Get every new post delivered to your Inbox.

Join 859 other followers