Bias and confounding in longitudinal measures of exhaled monoxides

Dorevitch, Samuel; Demirtaş, Hakan; Scheff, Peter A.; Persky, Victoria

doi:10.1038/sj.jes.7500545

Cited by 7 publications

(5 citation statements)

References 41 publications

(56 reference statements)

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“…Averaging times for the meteorologic variables were matched to the corresponding air pollutant variables of interest. Even though our eNO measurement method was designed to remove nitric oxide (NO) from inhaled air, in models predicting eNO we included control for indoor NO levels based on previous research supporting this approach ( Dorevitch et al 2007 ). Indoor NO levels were significant predictors of eNO, and associations between eNO and pollutant metrics were attenuated by 12% on average without indoor NO in the models; however, excluding indoor NO did not affect the overall significance of associations.…”

Section: Methodsmentioning

confidence: 99%

Air Pollution and Acute Respiratory Response in a Panel of Asthmatic Children along the U.S.–Mexico Border

Sarnat

Raysoni

et al. 2012

Environ Health Perspect

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Background: Concerns regarding the health impact of urban air pollution on asthmatic children are pronounced along the U.S.–Mexico border because of rapid population growth near busy border highways and roads.Objectives: We conducted the first binational study of the impacts of air pollution on asthmatic children in Ciudad Juarez, Mexico, and El Paso, Texas, USA, and compared different exposure metrics to assess acute respiratory response.Methods: We recruited 58 asthmatic children from two schools in Ciudad Juarez and two schools in El Paso. A marker of airway inflammation [exhaled nitric oxide (eNO)], respiratory symptom surveys, and pollutant measurements (indoor and outdoor 48-hr size-fractionated particulate matter, 48-hr black carbon, and 96-hr nitrogen dioxide) were collected at each school for 16 weeks. We examined associations between the pollutants and respiratory response using generalized linear mixed models.Results: We observed small but consistent associations between eNO and numerous pollutant metrics, with estimated increases in eNO ranging from 1% to 3% per interquartile range increase in pollutant concentrations. Effect estimates from models using school-based concentrations were generally stronger than corresponding estimates based on concentrations from ambient air monitors. Both traffic-related and non–traffic-related particles were typically more robust predictors of eNO than was nitrogen dioxide, for which associations were highly sensitive to model specification. Associations differed significantly across the four school-based cohorts, consistent with heterogeneity in pollutant concentrations and cohort characteristics. Models examining respiratory symptoms were consistent with the null.Conclusions: The results indicate adverse effects of air pollution on the subclinical respiratory health of asthmatic children in this region and provide preliminary support for the use of air pollution monitors close to schools to track exposure and potential health risk in this population.

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Section: Methodsmentioning

confidence: 99%

Air Pollution and Acute Respiratory Response in a Panel of Asthmatic Children along the U.S.–Mexico Border

Sarnat

Raysoni

et al. 2012

Environ Health Perspect

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“…319 In addition, environmental exposure to CO may affect eCO measurements, potentially giving falsely high results. 311,320 High ambient (e.g., near traffic) or indoor (e.g., secondhand smoke) CO concentrations should be avoided where eCO is being measured.…”

Section: Respiratory End Pointsmentioning

confidence: 99%

Noninvasive effects measurements for air pollution human studies: methods, analysis, and implications

Mirowsky

Gordon

2015

J Expo Sci Environ Epidemiol

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Human exposure studies, compared with cell and animal models, are heavily relied upon to study the associations between health effects in humans and air pollutant inhalation. Human studies vary in exposure methodology, with some work conducted in controlled settings, whereas other studies are conducted in ambient environments. Human studies can also vary in the health metrics explored, as there exists a myriad of health effect end points commonly measured. In this review, we compiled mini reviews of the most commonly used noninvasive health effect end points that are suitable for panel studies of air pollution, broken into cardiovascular end points, respiratory end points, and biomarkers of effect from biological specimens. Pertinent information regarding each health end point and the suggested methods for mobile collection in the field are assessed. In addition, the clinical implications for each health end point are summarized, along with the factors identified that can modify each measurement. Finally, the important research findings regarding each health end point and air pollutant exposures were reviewed. It appeared that most of the adverse health effects end points explored were found to positively correlate with pollutant levels, although differences in study design, pollutants measured, and study population were found to influence the magnitude of these effects. Thus, this review is intended to act as a guide for researchers interested in conducting human exposure studies of air pollutants while in the field, although there can be a wider application for using these end points in many epidemiological study designs.

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“…The number of cigarettes smoked, the inhalation of tobacco smoke and the CO levels measured inside the apartments were significant predictors of the CO exhaled levels. Dorevitch et al (2007) evaluated the levels of CO exhaled by 27 subjects who are the residents of public housing and concluded that exhaled concentrations were more strongly associated with indoor than with outdoor concentrations [33]. Approximately half of the variability in exhaled monoxide concentrations over time can be explained by changes in indoor monoxide concentrations.…”

Section: Personal Co Exposurementioning

confidence: 99%

Indoor and Personal Carbon Monoxide Exposure Risk Assessment in Sample of Apartment Buildings in Santiago, Chile

Martínez

Caba

Alvarado

et al. 2011

Indoor and Built Environment

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Indoor carbon monoxide (CO) exposure is considered around the world as one of the most important causes of poisoning with fatal outcomes. This study determined indoor CO levels and personal CO exposure and related risk factors during human activities in 96 apartments in a community of Santiago, Chile during the period from September to December of 2003. Indoor levels and personal exposure were determined using fixed, personal and single-breath CO monitors, respectively. Exposure risk factors and time-activities patterns were evaluated through an ad hoc exposure assessment questionnaire. Regression models were fitted to evaluate the effects of these risks factors on the personal CO levels. The median indoor CO level was 1 ppm; interquartile range (IQR): (0–1). The median personal CO level was 1 ppm; IQR: (0–7); CO exhaled was 3.0 ppm; IQR: (1–33). The number of cigarettes smoked and the levels of indoor environmental CO were significant predictors of the concentration of CO exhaled. This study showed that indoor median levels were below the national standard and the most important predictors of CO exposure were tobacco smoke and the smoking habit in apartments.

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Bias and confounding in longitudinal measures of exhaled monoxides

Cited by 7 publications

References 41 publications

Air Pollution and Acute Respiratory Response in a Panel of Asthmatic Children along the U.S.–Mexico Border

Air Pollution and Acute Respiratory Response in a Panel of Asthmatic Children along the U.S.–Mexico Border

Noninvasive effects measurements for air pollution human studies: methods, analysis, and implications

Indoor and Personal Carbon Monoxide Exposure Risk Assessment in Sample of Apartment Buildings in Santiago, Chile

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