Case???Crossover Analyses of Air Pollution Exposure Data

Janes, Holly; Sheppard, Lianne; Lumley, Thomas

doi:10.1097/01.ede.0000181315.18836.9d

Cited by 639 publications

(303 citation statements)

References 42 publications

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“…When same‐month subsequent events were excluded from the analysis, the results were nearly identical. The time‐stratified case‐crossover design with control or referent periods in the same month before and after the event period should provide unbiased effect estimates 25, 26. To check this assumption, a sensitivity analysis was conducted with control or referent periods matched on the same day of week for the 3 weeks prior to the event with no referent periods following the event.…”

Section: Discussionmentioning

confidence: 99%

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Short‐Term Exposure to Fine Particulate Matter Air Pollution Is Preferentially Associated With the Risk of ST‐Segment Elevation Acute Coronary Events

Pope

Muhlestein

Anderson

et al. 2015

JAHA

120

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BackgroundAir pollution is associated with greater cardiovascular event risk, but the types of events and specific persons at risk remain unknown. This analysis evaluates effects of short‐term exposure to fine particulate matter air pollution with risk of acute coronary syndrome events, including ST‐segment elevation myocardial infarction, non–ST‐segment elevation myocardial infarction, unstable angina, and non–ST‐segment elevation acute coronary syndrome.Methods and ResultsAcute coronary syndrome events treated at Intermountain Healthcare hospitals in urban areas of Utah's Wasatch Front were collected between September 1993 and May 2014 (N=16 314). A time‐stratified case‐crossover design was performed matching fine particulate matter air pollution exposure at the time of each event with referent periods when the event did not occur. Patients served as their own controls, and odds ratios were estimated using nonthreshold and threshold conditional logistic regression models. In patients with angiographic coronary artery disease, odds ratios for a 10‐μg/m3 increase in concurrent‐day fine particulate matter air pollution >25 μg/m³ were 1.06 (95% CI 1.02–1.11) for all acute coronary syndrome, 1.15 (95% CI 1.03–1.29) for ST‐segment elevation myocardial infarction, 1.02 (95% CI 0.97–1.08) for non–ST‐segment elevation myocardial infarction, 1.09 (95% CI 1.02–1.17) for unstable angina, and 1.05 (95% CI 1.00–1.10) for non–ST‐segment elevation acute coronary syndrome events. Excess risk from fine particulate matter air pollution exposure was not observed in patients without angiographic coronary artery disease.ConclusionsElevated fine particulate matter air pollution exposures contribute to triggering acute coronary events, especially ST‐segment elevation myocardial infarction, in those with existing seriously diseased coronary arteries but not in those with nondiseased coronary arteries.

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Section: Discussionmentioning

confidence: 99%

“…The primary statistical analysis of ACS events and ambient PM 2.5 is based on a time‐stratified case‐crossover design 24, 25, 26. This approach matches exposures at the time of event with ≥1 period when the event did not occur (control or referent periods) and estimates the potential excess risk using conditional logistic regression.…”

Section: Methodsmentioning

confidence: 99%

Short‐Term Exposure to Fine Particulate Matter Air Pollution Is Preferentially Associated With the Risk of ST‐Segment Elevation Acute Coronary Events

Pope

Muhlestein

Anderson

et al. 2015

JAHA

120

View full text Add to dashboard Cite

show abstract

“…By definition, in the case-crossover tech nique the cases act as their own controls on a set of pre defined control days proximate to the time they become cases. A time-stratified approach to determine referent control periods was widely adopted as it has been shown to produce unbiased conditional logistic regression esti mates [12]. In the design, the controls are matched to the case periods by the day of the week for the case pe riod (usually day), the control periods are determined as other days in the same month and year.…”

Section: Methodsmentioning

confidence: 99%

Ambient ozone and emergency department visits due to lower respiratory condition

Kousha¹,

Rowe²

2014

International Journal of Occupational Medicine and Environmental Health

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Objectives: Ambient ozone (O 3 ) exposure is associated with a variety of health conditions. The objective of this study was to examine the effect of increased daily concentrations of ozone on emergency department (ED) visits due to lower respi ratory diseases (LRD), such as acute or chronic bronchitis, in Edmonton, Canada. Materials and Methods: Data concer ning 10 years (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002) were obtained from 5 Edmonton hospital Emergency Departments. Odds ratios (ORs) for ED visits associated with the increased ozone levels were calculated employing a case-crossover technique with a time-stratified strategy to define controls. In the constructed conditional logistic regression models, adjustments were made for daily num ber of influenza ED visits and weather variables using natural splines. ORs and their 95% confidence intervals (95% CI) were reported in relation to an increase in the interquartile range (IQR = 17.9 ppb) of the ground-level ozone. Results: Over all, 48 252 ED visits due to LRD were identified, of which 53% were made by males. The presentations peaked in December (12%) and February (11.7%) and were the lowest in August (5.6%). Positive and statistically significant results were obtained for acute bronchitis: for same day (OR = 1.09, 95% CI: 1.05-1.13, lag 0) and for lag 2, lag 3-7 and 9 days; for chronic bronchi tis: for lag 6, 7, and lag 9 days (OR = 1.11, 95% CI: 1.05-1.18, lag 9). For all ED visits for LRD, lag 0, lag 1, and lag 3-9 days showed positive and statistically significant associations (OR = 1.06, 95% CI: 1.03-1.09, lag 0). Conclusions: These findings support the hypothesis concerning positive associations between ozone and the ED visits due to LRD.

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“…For example if a subject was hospitalized Saturday December 11th 2004, the other Saturdays of the month (December 4, 18, 21) were its control dates. This design allows us to control for secular trends in our hospitalization data (Janes, Sheppard, & Lumley, 2005;Maclure, 1991).…”

Section: Statistical Analysesmentioning

confidence: 99%

Hospitalizations for Respiratory Problems and Exposure to Industrial Emissions in Children

Labelle¹,

Brand²,

Buteau³

et al. 2015

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Industrial activities such as metal smelting, petroleum refining, and open mining emit air pollutants that can affect the health of surrounding communities. Few studies have assessed respiratory effects of acute exposure to industrial air emissions in children. In this study, we examined the association between daily exposure to air emissions from an industrial complex and hospitalizations for respiratory problems of children living nearby using a case crossover design. We used hospitalizations for respiratory problems of children under 5 years old living within 7.5 km of the industrial complex from January 1, 2001 to December 31, 2010. Pollutant exposure was estimated using daily mean and maximum concentrations of SO 2 and PM 2.5 at fixed monitoring stations located near the complex. We also calculated the daily percentage of hours that a child's residence was downwind of the industrial complex as an indicator of exposure to emissions. Odds-ratios were adjusted for temperature, relative humidity and wind speed, and calculated using conditional logistic regressions, reported by increases of interquartile range. A significant positive association was found between hospitalization for asthma or bronchiolitis and the percentage of hours downwind (OR: 1.11, 95% CI=1.01-1.22) but large statistical variability was noted for associations with all three exposure metrics (OR maximum SO 2 levels: 1.06, 95% CI=0.98-1.15; OR daily maximum PM 2.5 levels: 0.97, 95% CI=0.86-1.09). The results suggest that exposure to the mixture of air pollutant emissions from an industrial complex may induce respiratory health problems in children residing nearby.

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Case???Crossover Analyses of Air Pollution Exposure Data

Cited by 639 publications

References 42 publications

Short‐Term Exposure to Fine Particulate Matter Air Pollution Is Preferentially Associated With the Risk of ST‐Segment Elevation Acute Coronary Events

Short‐Term Exposure to Fine Particulate Matter Air Pollution Is Preferentially Associated With the Risk of ST‐Segment Elevation Acute Coronary Events

Ambient ozone and emergency department visits due to lower respiratory condition

Hospitalizations for Respiratory Problems and Exposure to Industrial Emissions in Children

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