The association between childhood asthma prevalence and monitored air pollutants in metropolitan areas, United States, 2001-2004

Population study on chronic and acute conjunctivitis associated with ambient environment in urban and rural areas

The objective of this study is to evaluate whether daily clinic visits for conjunctivitis are associated with the ambient environment in urban and rural areas of Taiwan. The incidences of acute and chronic conjunctivitis (International Classification of Disease 9 Clinical Modification 372.0 and 372.1) in two urban cities and two rural counties and their relative risks (RRs) are associated with air pollutants (nitrogen oxides (NOx), sulfur dioxide, ozone, and particulate matter <10 μm in aerodynamic diameter) and/or weather statuses were assessed from the insurance reimbursement claims of a representative 1 million people from 2000 to 2007. The patients resided in rural counties were approximately eight time more likely to have acute complains and >1.3 time more likely to have chronic complaints than the patients lived in the capital, Taipei. Per 10 °C increment of the daily average temperature increased the risk of acute conjunctivitis and chronic conjunctivitis with RRs of 1.06 (95% confidence interval (CI): 1.03-1.09) and 1.05 (95% CI: 1.04-1.07), respectively. A 10-p.p.b. increase in NOx concentration also increased the risk of acute conjunctivitis (RR=1.03, 95% CI: 1.02-1.04) and chronic conjunctivitis (RR=1.06, 95% CI: 1.05-1.06). Residents in rural counties, females, the elderly, and children have higher risk of conjunctivitis. Ambient temperature and NOx concentration can cause greater significant risks on the diseases.

Deficiencies in culturally competent asthma care for ethnic minority children: a qualitative assessment among care providers

Background

Asthma outcomes are generally worse for ethnic minority children. Cultural competence training is an instrument for improving healthcare for ethnic minority patients. To develop effective training, we explored the mechanisms in paediatric asthma care for ethnic minority patients that lead to deficiencies in the care process.

Methods

We conducted semi-structured interviews on care for ethnic minority children with asthma (aged 4-10 years) with paediatricians (n = 13) and nurses (n = 3) in three hospitals. Interviews were analysed qualitatively with a framework method, using a cultural competence model.

Results

Respondents mentioned patient non-adherence as the central problem in asthma care. They related non-adherence in children from ethnic minority backgrounds to social context factors, difficulties in understanding the chronic nature of asthma, and parents’ language barriers. Reactions reported by respondents to patients’ non-adherence included retrieving additional information, providing biomedical information, occasionally providing referrals for social context issues, and using informal interpreters.

Conclusions

This study provides keys to improve the quality of specialist paediatric asthma care to ethnic minority children, mainly related to non-adherence. Care providers do not consciously recognise all the mechanisms that lead to deficiencies in culturally competent asthma care they provide to ethnic minority children (e.g. communicating mainly from a biomedical perspective and using mostly informal interpreters). Therefore, the learning objectives of cultural competence training should reflect issues that care providers are aware of as well as issues they are unaware of.

Hormones and endocrine-disrupting chemicals: low-dose effects and nonmonotonic dose responses

For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of "the dose makes the poison," because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from the cell culture, animal, and epidemiology literature. We illustrate that nonmonotonic responses and low-dose effects are remarkably common in studies of natural hormones and EDCs. Whether low doses of EDCs influence certain human disorders is no longer conjecture, because epidemiological studies show that environmental exposures to EDCs are associated with human diseases and disabilities. We conclude that when nonmonotonic dose-response curves occur, the effects of low doses cannot be predicted by the effects observed at high doses. Thus, fundamental changes in chemical testing and safety determination are needed to protect human health.

An analysis of asthma hospitalizations, air pollution, and weather conditions in Los Angeles County, California

There is now a large body of literature supporting a linkage between exposure to air pollutants and asthma morbidity. However, the extent and significance of this relationship varies considerably between pollutants, location, scale of analysis, and analysis methods. Our primary goal is to evaluate the relationship between asthma hospitalizations, levels of ambient air pollution, and weather conditions in Los Angeles (LA) County, California, an area with a historical record of heavy air pollution. County-wide measures of carbon monoxide (CO), nitrogen dioxide (NO(2)), ozone (O(3)), particulate matter<10 μm (PM(10)), particulate matter<2.5 μm (PM(2.5)), maximum temperature, and relative humidity were collected for all months from 2001 to 2008. We then related these variables to monthly asthma hospitalization rates using Bayesian regression models with temporal random effects. We evaluated model performance using a goodness of fit criterion and predictive ability. Asthma hospitalization rates in LA County decreased between 2001 and 2008. Traffic-related pollutants, CO and NO(2), were significant and positively correlated with asthma hospitalizations. PM(2.5) also had a positive, significant association with asthma hospitalizations. PM(10), relative humidity, and maximum temperature produced mixed results, whereas O(3) was non-significant in all models. Inclusion of temporal random effects satisfies statistical model assumptions, improves model fit, and yields increased predictive accuracy and precision compared to their non-temporal counterparts. Generally, pollution levels and asthma hospitalizations decreased during the 9 year study period. Our findings also indicate that after accounting for seasonality in the data, asthma hospitalization rate has a significant positive relationship with ambient levels of CO, NO(2), and PM(2.5).

Indoor air pollutants and health in the United Arab Emirates

BACKGROUND

Comprehensive global data on the health effects of indoor air pollutants are lacking. There are few large population-based multi-air pollutant health assessments. Further, little is known about indoor air health risks in the Middle East, especially in countries undergoing rapid economic development.

OBJECTIVES

To provide multifactorial indoor air exposure and health data, we conducted a population-based study of indoor air pollution and health in the United Arab Emirates (UAE).

METHODS

We conducted a cross-sectional study in a population-based sample of 628 households in the UAE. Indoor air pollutants [sulfur dioxide (SO2), nitrogen dioxide (NO2), hydrogen sulfide (H2S), formaldehyde (HCHO), carbon monoxide (CO), and particulate matter] were measured using passive samplers over a 7-day period. Health information was collected from 1,590 household members via in-person interviews.

RESULTS

Participants in households with quantified SO2, NO2, and H2S (i.e., with measured concentrations above the limit of quantification) were twice as likely to report doctor-diagnosed asthma. Participants in homes with quantified SO2 were more likely to report wheezing symptoms {ever wheezing, prevalence odds ratio [POR] 1.79 [95% confidence interval (CI) 1.05, 3.05]; speech-limiting wheeze, POR 3.53 (95% CI: 1.06, 11.74)}. NO2 and H2S were similarly associated with wheezing symptoms. Quantified HCHO was associated with neurologic symptoms (difficulty concentrating POR 1.47; 95% CI: 1.02, 2.13). Burning incense daily was associated with increased headaches (POR 1.87; 95% CI: 1.09, 3.21), difficulty concentrating (POR 3.08; 95% CI: 1.70, 5.58), and forgetfulness (POR 2.68: 95% CI: 1.47, 4.89).

CONCLUSIONS

This study provides new information regarding potential health risks from pollutants commonly found in indoor environments in the UAE and other countries. Multipollutant exposure and health assessments in cohort studies are needed to better characterize health effects of indoor air pollutants.

Monitoring air pollution: use of early warning systems for public health

Research confirming the detrimental impact poor ambient air quality and episodes of abnormally high pollutants has on public health, plus differential susceptibility, calls for improved understanding of this complex topic among all walks of society. The public and particularly, vulnerable groups, should be aware of their quality of air, enabling action to be taken in the event of increased pollution. Policy makers must have a sound awareness of current air quality and future trends, to identify issues, guide policies and monitor their effectiveness. These attitudes are dependent upon air pollution monitoring, forecasting and reporting, serving all interested parties. Apart from the underlying national regulatory obligation a country has in reporting air quality information, data output serves several purposes. This review focuses on provision of real-time data and advanced warnings of potentially health-damaging events, in the form of national air quality indices and proactive alert services. Some of the challenges associated with designing these systems include technical issues associated with the complexity of air pollution and its science. These include inability to provide precise exposure concentrations or guidance on long-term/cumulative exposures or effects from pollutant combinations. Other issues relate to the degree to which people are aware and positively respond to these services. Looking to the future, mobile devices such as cellular phones, equipped with sensing applications have potential to provide dynamic, temporally and spatially precise exposure measures for the mass population. The ultimate aim should be to empower people to modify behaviour-for example, when to increase medication, the route/mode of transport taken to school or work or the appropriate time to pursue outdoor activities-in a way that protects their health as well as the quality of the air they breathe.

High prevalence of childhood asthma in Northern Israel is linked to air pollution by particulate matter: evidence from GIS analysis and Bayesian Model Averaging

The medical records of 3922 school children residing in the Greater Haifa Metropolitan Area in Northern Israel were analyzed. Individual exposure to ambient air pollution (SO(2) and PM(10)) for each child was estimated using Geographic Information Systems tools. Factors affecting childhood asthma risk were then investigated using logistic regression and the more recently developed Bayesian Model Averaging (BMA) tools. The analysis reveals that childhood asthma in the study area appears to be significantly associated with particulate matter of less than 10 μm in aerodynamic diameter (PM(10)) (Odds Ratio (OR) = .11; P<0.001). However, no significant association with asthma prevalence was found for SO(2) (P >0.2), when PM(10) and SO(2) were introduced into the models simultaneously. When considering a change in PM(10) between the least and the most polluted parts of the study area (9.4 μg/m(3)), the corresponding OR, calculated using the BMA analysis, is 2.58 (with 95% posterior probability limits of OR ranging from 1.52 to 4.41), controlled for gender, age, proximity to main roads, the town of a child's residence, and family's socio-economic status. Thus, it is concluded that exposure to airborne particular matter, even at relatively low concentrations (40-50 μg/m(3)), generally below international air pollution standards (55-70 μg/m(3)), appears to be a considerable risk factor for childhood asthma in urban areas. This should be a cause of concern for public health authorities and environmental decision-makers.

Effects of physical activity on the deposition of traffic-related particles into the human lungs in silico

Traffic-related particle emissions have been a great concern over a number of years due to their adverse health effects. In this research project, traffic-related particle deposition in the human lungs is studied using lung deposition estimates based on the ICRP 66 model. This study covers four human groups, i.e. adult males, adult females and two groups of children aged 5 and 10 years. The study examines particle deposition in the human lungs in relation to four different physical exercise levels, i.e. sleeping, sitting, light exercise and heavy exercise. To conduct the study, the particle size distributions of diesel and compressed natural gas (CNG) busses were monitored in field laboratory conditions. The study indicates that the total number of diesel particles measured is greater than the total number of CNG particles. The results further display that most of the diesel particles measured are smaller than 0.2 μm, whereas the CNG particles are smaller than 0.05 μm in aerodynamic diameter. The level of physical exercise, as well as the age and gender of a person affects the deposition of particles in the lungs. An increase in the physical activity results in larger amounts of small-size particles penetrating deeper into the respiratory system. The lung deposition of particles in males was substantially different compared to that of females and children. The deposited dose of particles was generally lower for females than for males and further lower for children than for females. This article argues that these groups should be discussed separately when conducting exposure assessments and that the level of physical activity should be taken into account when assessing potential health consequences.

The effects of outdoor air pollutants on the costs of pediatric asthma hospitalizations in the United States, 1999 to 2007

BACKGROUND

Acute exposure to outdoor air pollutants has been associated with increased pediatric asthma morbidity. However, the impact of subchronic exposures is largely unknown.

OBJECTIVE

To examine the association between subchronic exposure to 6 outdoor air pollutants (PM2.5, PM10, ozone, nitrogen oxides, sulfur oxides, carbon monoxide) and pediatric asthma hospitalization length of stay, charges, and costs.

METHODS

We linked pediatric asthma hospitalization discharge data from a nationally representative dataset, the 1999-2007 Nationwide Inpatient Sample, with outdoor air pollution data from the Environmental Protection Agency. Hospitals with no air quality data within 10 miles were excluded. Our predictor was the average concentration of 6 pollutants near the hospital during the month of admission. We conducted bivariate analyses using Spearman correlations and multivariable analyses using Poisson regression for length of stay and linear regression for log-transformed charges and costs, controlling for patient demographics, hospital characteristics, and month of admission.

RESULTS

In unadjusted analyses, all 6 pollutants had minimal correlation with the 3 outcomes (ρ<0.1, P<0.001). In multivariable analyses, a 1-unit (μg/m) increase in monthly PM2.5 led to a $123 increase in charges (95% confidence interval $40-249) and a $47 increase in costs (95% confidence interval $15-93). No other pollutants were significant predictors of charges or costs or length of stay.

CONCLUSION

Subchronic PM2.5 exposure is associated with increased costs for pediatric asthma hospitalizations. Policy changes to reduce outdoor subchronic pollutant exposure may lead to improved asthma outcomes and substantial savings in healthcare spending.

Biochemical effects of ozone on asthma during postnatal development

BACKGROUND

Ozone exposure during early life has the potential to contribute to the development of asthma as well as to exacerbate underlying allergic asthma.

SCOPE OF REVIEW

Developmentally regulated aspects of sensitivity to ozone exposure and downstream biochemical and cellular responses.

MAJOR CONCLUSIONS

Developmental differences in antioxidant defense responses, respiratory physiology, and vulnerabilities to cellular injury during particular developmental stages all contribute to disparities in the health effects of ozone exposure between children and adults.

GENERAL SIGNIFICANCE

Ozone exposure has the capacity to affect multiple aspects of the "effector arc" of airway hyperresponsiveness, ranging from initial epithelial damage and neural excitation to neural reprogramming during infancy. This article is part of a Special Issue entitled: Biochemistry of Asthma.

Postnatal episodic ozone results in persistent attenuation of pulmonary and peripheral blood responses to LPS challenge

Early life is a dynamic period of growth for the lung and immune system. We hypothesized that ambient ozone exposure during postnatal development can affect the innate immune response to other environmental challenges in a persistent fashion. To test this hypothesis, we exposed infant rhesus macaque monkeys to a regimen of 11 ozone cycles between 30 days and 6 mo of age; each cycle consisted of ozone for 5 days (0.5 parts per million at 8 h/day) followed by 9 days of filtered air. Animals were subsequently housed in filtered air conditions and challenged with a single dose of inhaled LPS at 1 yr of age. After completion of the ozone exposure regimen at 6 mo of age, total peripheral blood leukocyte and polymorphonuclear leukocyte (PMN) numbers were reduced, whereas eosinophil counts increased. In lavage, total cell numbers at 6 mo were not affected by ozone, however, there was a significant reduction in lymphocytes and increased eosinophils. Following an additional 6 mo of filtered air housing, only monocytes were increased in blood and lavage in previously exposed animals. In response to LPS challenge, animals with a prior history of ozone showed an attenuated peripheral blood and lavage PMN response compared with controls. In vitro stimulation of peripheral blood mononuclear cells with LPS resulted in reduced secretion of IL-6 and IL-8 protein in association with prior ozone exposure. Collectively, our findings suggest that ozone exposure during infancy can result in a persistent effect on both pulmonary and systemic innate immune responses later in life.