Juan C. Correa

Particulate Air Pollution, Metabolic Syndrome, and Heart Rate Variability: The Multi-Ethnic Study of Atherosclerosis (MESA)

Background Cardiac autonomic dysfunction has been suggested as a possible biologic pathway for the association between fine particulate matter ≤ 2.5 μm in diameter (PM2.5) and cardiovascular disease (CVD). We examined the associations of PM2.5 with heart rate variability, a marker of autonomic function, and whether metabolic syndrome (MetS) modified these associations. Methods We used data from the Multi-Ethnic Study of Atherosclerosis to measure the standard deviation of normal-to-normal intervals (SDNN) and the root mean square of successive differences (rMSSD) of 5,465 participants 45–84 years old who were free of CVD at the baseline examination (2000–2002). Data from the U.S. regulatory monitor network were used to estimate ambient PM2.5 concentrations at the participants’ residences. MetS was defined as having three or more of the following criteria: abdominal obesity, hypertriglyceridemia, low high-density lipoprotein cholesterol, high blood pressure, and high fasting glucose. Results After controlling for confounders, we found that an interquartile range (IQR) increase in 2-day average PM2.5 (10.2 μg/m3) was associated with a 2.1% decrease in rMSSD [95% confidence interval (CI), −4.2 to 0.0] and nonsignificantly associated with a 1.8% decrease in SDNN (95% CI, −3.7 to 0.1). Associations were stronger among individuals with MetS than among those without MetS: an IQR elevation in 2-day PM2.5 was associated with a 6.2% decrease in rMSSD (95% CI, −9.4 to −2.9) among participants with MetS, whereas almost no change was found among participants without MetS (p-interaction = 0.005). Similar effect modification was observed in SDNN (p-interaction = 0.011). Conclusion These findings suggest that autonomic dysfunction may be a mechanism through which PM exposure affects cardiovascular risk, especially among persons with MetS.

Traffic-Related Particulate Matter and Acute Respiratory Symptoms among New York City Area Adolescents

Background Exposure to traffic-related particulate matter (PM) has been associated with adverse respiratory health outcomes in children. Diesel exhaust particles (DEPs) are a local driver of urban fine PM [aerodynamic diameter ≤ 2.5 μm (PM2.5)]; however, evidence linking ambient DEP exposure to acute respiratory symptoms is relatively sparse, and susceptibilities of urban and asthmatic children are inadequately characterized. Objectives We examined associations of daily ambient black carbon (BC) concentrations, a DEP indicator, with daily respiratory symptoms among asthmatic and nonasthmatic adolescents in New York City (NYC) and a nearby suburban community. Methods BC and PM2.5 were monitored continuously outside three NYC high schools and one suburban high school for 4–6 weeks, and daily symptom data were obtained from 249 subjects (57 asthmatics, 192 nonasthmatics) using diaries. Associations between pollutants and symptoms were characterized using multilevel generalized linear mixed models, and modification by urban residence and asthma status were examined. Results Increases in BC were associated with increased wheeze, shortness of breath, and chest tightness. Multiple lags of nitrogen dioxide (NO2) exposure were associated with symptoms. For several symptoms, associations with BC and NO2 were significantly larger in magnitude among urban subjects and asthmatics compared with suburban subjects and nonasthmatics, respectively. PM2.5 was not consistently associated with increases in symptoms. Conclusions Acute exposures to traffic-related pollutants such as DEPs and/or NO2 may contribute to increased respiratory morbidity among adolescents, and urban residents and asthmatics may be at increased risk. The findings provide support for developing additional strategies to reduce diesel emissions further, especially in populations susceptible because of environment or underlying respiratory disease.

On the Front Lines: An Environmental Asthma Intervention in New York City

Asthma is now the leading cause of school absence among children of color in impoverished urban neighborhoods. Environmental interventions have the potential to augment clinical approaches to asthma management by directly reducing exposure to environmental triggers (e.g., cockroaches, rodents, and mold). We implemented an apartment-based intervention to reduce exposures to indoor allergens among children living with asthma in 2 areas in New York City with rates of asthma morbidity and mortality that rank among the highest in the United States. Although the intervention phase of the present study is not yet complete, timely reporting of our field experiences may prove useful to other groups engaged in environmental intervention trials in urban communities.

Mite sensitization among Latina women in New York, where dust‐mite allergen levels are typically low

UNLABELLED In New York (NY), Latinos often have greater asthma morbidity than other ethnicities, and dust-mite sensitization is common despite low allergen levels. We investigated mite allergen exposure and sensitization in atopic and/or asthmatic women, the majority being Puerto Rican. Women (n = 274) recruited for a birth cohort study were visited postnatally. Dust from their homes was analyzed for mite allergens (Der f 1, Der p 1, and Blo t 5). Serum was analyzed for total and allergen-specific IgE. Thirty-seven percent were sensitized to Dermatophagoides pteronyssinus, 34% to Dermatophagoides farinae, and 21% to Blomia tropicalis. Only 5% of NY homes had levels of Der f 1 >2 microg/g; none had Blo t 5 or Der p 1 above this level. Caribbean or Latin American birthplace (a proxy for childhood exposure) was not associated with mite sensitization. Sensitization to D. pteronyssinus and D. farinae was associated with a report of doctor-diagnosed asthma [Odds ratio (OR) = 3.27, P = 0.003; OR = 2.81, P = 0.010, respectively]; sensitization to any mite was associated with asthma medication use in the past 12 months (OR = 3.12, P = 0.004). These associations held even after adjustment for cockroach, mouse, and cat sensitization. PRACTICAL IMPLICATIONS Despite the low concentrations of mite allergen in our community, many of the women in the atopically enriched cohort were sensitized to mites, even Blomia tropicalis which is typically found only in tropical environments.

Quantitative measurement of airborne cockroach allergen in New York City apartments.

UNLABELLED We designed and tested a sampling and analysis system for quantitative measurement of airborne cockroach allergen with sufficient sensitivity for residential exposure assessment. Integrated 1-week airborne particle samples were collected at 10-15 LPM in 19 New York City apartments in which an asthmatic child who was allergic to cockroach allergen resided. Four simultaneous air samples were collected in each home: at heights of 0.3 and 1 m in the childs bedroom and in the kitchen. Extracts of air samples were analyzed by ELISA for the cockroach allergen Bla g2, modified by amplifying the colorimetric signal generated via use of AMPLI-Q detection system (DAKO Corporation, Carpinteria, CA, USA). Settled dust samples were quantified by conventional ELISA. Of the homes where cockroach allergen was detected in settled dust, Bla g2 also was detected in 87% and 93% of air samples in the bedroom and kitchen, respectively. Airborne Bla g2 levels were highly correlated within and between the bedroom and kitchen locations (P < 0.001). Expressed as picogram per cubic meter, the room average geometric mean for Bla g2 concentrations was 1.9 pg/m³ (95% CI 0.63, 4.57) and 3.8 pg/m³ (95% CI 1.35, 9.25) in bedrooms and kitchens, respectively. This method offers an attractive supplement to settled dust sampling for cockroach allergen exposure health studies. PRACTICAL IMPLICATIONS Until now, cockroach allergen exposures have usually been assessed by collection and analysis of settled dust, on the assumption that airborne cockroach allergen cannot be reliably measured. In this study, a sensitive and quantitative method for measuring indoor airborne exposures to cockroach allergens involving a 7-day integrated total suspended particulate (TSP) sample collected at approximately 10-15 l/min was developed. Investigators are now empowered with an alternative exposure assessment method to supplement their studies and the understanding of allergen aerodynamics in the homes of children with asthma. We report airborne cockroach allergen in apartments, suggesting an ongoing burden of inhalation exposure.

The New York City Puerto Rican Asthma Project: Study Design, Methods, and Baseline Results

Objective. We examined asthma risk factors among 274 Puerto Rican children born in New York to atopic mothers. Methods. We prospectively followed the cohort to measure aeroallergens in their homes and assess allergic sensitization. Baseline data are presented. Results. Maternal smoking was significantly higher among women born on the continental United States (25%) vs. those born elsewhere (11%). Cat ownership was more frequent among mainland-born women (15%) compared with those born in Puerto Rico (4%). While some aeroallergens were prevalent, few dust samples contained detectable dust mite allergens. Conclusions. By following this cohort, we hope to identify the roles that socio-cultural factors play in the process of allergic sensitization.

RESPIRATORY IMPACTS OF TRAFFIC-RELATED PARTICLE EXPOSURES ON URBAN YOUTH

Diesel exhaust particles (DEP) produce and or exacerbate airway inflammation in animal models, and have been associated with increased respiratory symptoms and diminished lung function in epidemiology studies. DEP is an important component of fine particulates in many urban areas. We hypothesized that respiratory symptom prevalence would differ across two schools that varied with respect to diesel traffic impacts, and that day to day changes in symptoms would correlate with daily concentrations of black carbon, a surrogate for DEP. One school was located along a major highway in an inner city neighborhood; the other was located in a suburban neighborhood upwind of the city. Air monitoring was carried out on the roofs of the two schools for hourly black carbon concentrations and integrated PM2.5 filters. In addition, a meteorological station was established on each school to assess wind speed and direction. Daily symptoms were assessed over a 4–6 week period at each school, with approximately 40 students participating at each school. On average, elemental carbon (EC) levels were approximately 3 fold higher on the urban schools vs. the suburban. Students from the urban school reported having higher bus and truck traffic in busy street close to their homes. Asthma prevalence (evaluated as ever having had diagnosed asthma by a physician) was higher at the urban school (p 0.007). This prevalence remained higher after controlling for differences in SES and ethnicity. In addition, daily symptoms were analyzed in relation to daily EC concentrations. Results of this study highlight the potential health impacts of emissions from traffic sources in inner city locations. This work was funded by NIEHS under grant ES011379.

Rat Sensitization Among Inner-City Asthmatic Children

Study objective: Inner-city asthma is a growing problem, and concerns remain about the role of exposure to multiple indoor allergens. Because of the increasing problems of rat infestation in New York and other cities, we sought to determine the frequency of sensitization to rat among inner-city children with asthma living in homes infested with cockroaches, and whether rat sensitization is associated with increased symptoms. Design/Setting/Participants: As part of the Columbia Intervention to Reduce Indoor Allergens Study, 37 Latino and African-American children age 5–18 years with asthma and determined to have positive skin tests to cockroach were evaluated for the presence of sensitization to rat by skin test and anti-rat-IgE levels. Clinical course was assessed by questionnaire. Results: We found that 43% had positive skin tests to rat, and 43% had an elevated anti-rat-IgE level. Anti-rat-IgE levels correlated with anti-cockroach-IgE levels (r =. 37, p =. 02) and mouse-IgE levels (r =. 72, p =. 001). O...