Background: Estimating the health effects of ambient air pollutant mixtures is necessary to understand the risk of real-life air pollution exposures.
Methods: Pediatric Emergency Department (ED) visit records for asthma or wheeze (n = 148,256), bronchitis (n = 84,597), pneumonia (n = 90,063), otitis media (n = 422,268) and upper respiratory tract infection (URI) (n = 744,942) were obtained from Georgia hospitals during 2002–2008. Spatially-contiguous daily concentrations of 11 ambient air pollutants were estimated from CMAQ model simulations that were fused with ground-based measurements. Using a case-crossover study design, odds ratios for 3-day moving average air pollutant concentrations were estimated using conditional logistic regression, matching on ZIP code, day-of-week, month, and year.
Results: In multipollutant models, the association of highest magnitude observed for the asthma/wheeze outcome was with “oxidant gases” (O3, NO2, and SO2); the joint effect estimate for an IQR increase of this mixture was OR: 1.068 (95% CI: 1.040, 1.097). The group of “secondary pollutants” (O3 and the PM2.5 components SO4 2−, NO3−, and NH4+) was strongly associated with bronchitis (OR: 1.090, 95% CI: 1.050, 1.132), pneumonia (OR: 1.085, 95% CI: 1.047, 1.125), and otitis media (OR: 1.059, 95% CI: 1.042, 1.077). ED visits for URI were strongly associated with “oxidant gases,” “secondary pollutants,” and the “criteria pollutants” (O3, NO2, CO, SO2, and PM2.5).
Conclusions: Short-term exposures to air pollution mixtures were associated with ED visits for several different pediatric respiratory diseases.
Background: Children may have differing susceptibility to ambient air pollution concentrations depending on various background characteristics of the children. Methods: Using emergency department (ED) data linked with birth records from Atlanta, Georgia, we identified ED visits for asthma or wheeze among children 2 to 16 years of age from 1 January 2002 through 30 June 2010 (n = 109,758). We stratified by preterm delivery, term low birth weight, maternal race, Medicaid status, maternal education, maternal smoking, delivery method, and history of a bronchiolitis ED visit. Population-weighted daily average concentrations were calculated for 1-hour maximum carbon monoxide and nitrogen dioxide; 8-hour maximum ozone; and 24-hour average particulate matter less than 10 microns in diameter, particulate matter less than 2.5 microns in diameter (PM<inf>2. 5</inf>), and the PM<inf>2. 5</inf> components sulfate, nitrate, ammonium, elemental carbon, and organic carbon, using measurements from stationary monitors. Poisson time-series models were used to estimate rate ratios for associations between 3-day moving average pollutant concentrations and daily ED visit counts and to investigate effect-measure modification by the stratification factors. Results: Associations between pollutant concentrations and asthma exacerbations were larger among children bom preterm and among children bom to African American mothers. Stratification by race and preterm status together suggested that both factors affected susceptibility. The largest estimated effect size (for an interquartile range increase in pollution) was observed for ozone among preterm births to African American mothers: rate ratio = 1.138 (95% confidence interval = 1.077-1.203). In contrast, the rate ratio for the ozone association among full-term births to mothers of other races was 1.025 (0.970-1.083). Conclusions: Results support the hypothesis that children vary in their susceptibility to ambient air pollutants.
Little is known about environmental determinants of sleep. We investigated the association between black carbon (BC), a marker of traffic-related air pollution, and sleep measures among participants of the Boston Area Community Health Survey. We also sought to assess the impact of sociodemographic factors, health conditions, and season on associations. Residential 24-h BC was estimated from a validated land-use regression model for 3821 participants and averaged over 1-6 months and 1 year. Sleep measures included questionnaire-assessed sleep duration, sleep latency, and sleep apnea. Linear and logistic regression models controlling for confounders estimated the association between sleep measures and BC. Effect modification was tested with interaction terms. Main effects were not observed between BC and sleep measures. However, in stratified models, males experienced 0.23 h less sleep (95% CI: -0.42, -0.03) and those with low SES 0.25 h less sleep (95% CI: -0.48, -0.01) per IQR increase in annual BC (0.21 μg/m<sup>3</sup>). In blacks, sleep duration increased with annual BC (β=0.34 per IQR; 95% CI: 0.12, 0.57). Similar findings were observed for short sleep (≤5 h). BC was not associated with sleep apnea or sleep latency, however, long-term exposure may be associated with shorter sleep duration, particularly in men and those with low SES, and longer sleep duration in blacks.
by
Gypsyamber D'Souza;
Thomas E. Carey;
William N. William,Jr.;
Minh Ly T Nguyen;
Eric C. Ko;
James Riddell,IV;
Sara I. Pai;
Vishal Gupta;
Heather M. Walline;
J. Jack Lee;
Gregory T. Wolf;
Dong M Shin;
Jennifer R. Grandis;
Robert L. Ferris
Background: HIV-infected individuals have a higher incidence of head and neck cancer (HNC).
Methods: Case series of 94 HIV-infected HNC patients (HIVHNC) at 6 tertiary care referral centers in the US between 1991 and 2011. Clinical and risk factor data were abstracted from the medical record. Risk factors for survival were analyzed using Cox proportional hazard models. Human papillomavirus (HPV) and p16 testing was performed in 46 tumors. Findings were compared with Surveillance Epidemiology and End Results HNC (US-HNC) data.
Results: This study represents the largest HIV-HNC series reported to date. HIV-HNC cases were more likely than US-HNC to be male (91% vs. 68%), younger (median age, 50 vs. 62 years), nonwhite (49% vs. 18%), and current smokers (61% vs. 18%). Median HIVHNC survival was not appreciably lower than US-HNC survival (63 vs. 61 months). At diagnosis, most cases were currently on highly active antiretroviral therapy (77%) but had detectable HIV viremia (99%), and median CD4 was 300 cells per microliter (interquartile range = 167-500). HPV was detected in 30% of HIV-HNC and 64% of HIV-oropharyngeal cases. Median survival was significantly lower among those with CD4 counts ≤200 than >200 cells per microliter at diagnosis (16.1 vs. 72.8 months, P > 0.001). In multivariate analysis, poorer survival was associated with CD4 >100 cells per microliter [adjusted hazard ratio (aHR) = 3.09, 95% confidence interval (CI): 1.15 to 8.30], larynx/hypopharynx site (aHR = 3.54, 95% CI: 1.34 to 9.35), and current tobacco use (aHR = 2.54, 95% CI: 0.96 to 6.76).
Conclusions: Risk factors for the development of HNC in patients with HIV infection are similar to the general population, including both HPV-related and tobacco/alcohol-related HNC.
Background: Characterizing multipollutant health effects is challenging. We use classification and regression trees to identify multipollutant joint effects associated with pediatric asthma exacerbations and compare these results with those from a multipollutant regression model with continuous joint effects. Methods: We investigate the joint effects of ozone, NO<inf>2</inf> and PM<inf>2.5</inf> on emergency department visits for pediatric asthma in Atlanta (1999-2009), Dallas (2006-2009) and St. Louis (2001-2007). Daily concentrations of each pollutant were categorized into four levels, resulting in 64 different combinations or "Day-Types" that can occur. Days when all pollutants were in the lowest level were withheld as the reference group. Separate regression trees were grown for each city, with partitioning based on Day-Type in a model with control for confounding. Day-Types that appeared together in the same terminal node in all three trees were considered to be mixtures of potential interest and were included as indicator variables in a three-city Poisson generalized linear model with confounding control and rate ratios calculated relative to the reference group. For comparison, we estimated analogous joint effects from a multipollutant Poisson model that included terms for each pollutant, with concentrations modeled continuously. Results and discussion: No single mixture emerged as the most harmful. Instead, the rate ratios for the mixtures suggest that all three pollutants drive the health association, and that the rate plateaus in the mixtures with the highest concentrations. In contrast, the results from the comparison model are dominated by an association with ozone and suggest that the rate increases with concentration. Conclusion: The use of classification and regression trees to identify joint effects may lead to different conclusions than multipollutant models with continuous joint effects and may serve as a complementary approach for understanding health effects of multipollutant mixtures.
Oxidative potential (OP) has been proposed as a measure of toxicity of ambient particulate matter (PM). OBJECTIVES: Our goal was to address an important research gap by using daily OP measurements to conduct population-level analysis of the health effects of measured ambient OP. METHODS: A semi-automated dithiothreitol (DTT) analytical system was used to measure daily average OP (OP DTT ) in water-soluble fine PM at a central monitor site in Atlanta, Georgia, over eight sampling periods (a total of 196 d) during June 2012–April 2013. Data on emergency department (ED) visits for selected cardiorespiratory outcomes were obtained for the five-county Atlanta metropolitan area. Poisson log-linear regression models controlling for temporal confounders were used to conduct time-series analyses of the relationship between daily counts of ED visits and either the 3-d moving average (lag 0–2) of OP DTT or same-day OP DTT . Bipollutant regression models were run to estimate the health associations of OP DTT while controlling for other pollutants. RESULTS: OP DTT was measured for 196 d (mean = 0:32 nmol/min/m 3 , interquartile range = 0:21). Lag 0–2 OP DTT was associated with ED visits for respiratory disease (RR = 1:03, 95% confidence interval (CI): 1.00, 1.05 per interquartile range increase in OP DTT ), asthma (RR = 1:12, 95% CI: 1.03, 1.22), and ischemic heart disease (RR = 1:19, 95% CI: 1.03, 1.38). Same-day OP DTT was not associated with ED visits for any outcome. Lag 0–2 OP DTT remained a significant predictor of asthma and ischemic heart disease in most bipollutant models. CONCLUSIONS: Lag 0–2 OP DTT was associated with ED visits for multiple cardiorespiratory outcomes, providing support for the utility of OP DTT as a measure of fine particle toxicity.