EVA study Emisiones Vehiculares y Asma

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EVA studyEmisiones Vehiculares y Asma

• Centers for Disease Control
• Air Pollution Respiratory Branch
• Instituto Nacional de Salud Pública
• Emory University School of Medicine
• Division of Pulmonary and Critical Care Medicine

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Background

• In Ciudad Juarez 93 of the truck industry and
  61.8 of the buses use diesel fuel
• Outdated vehicular fleet
• Vehicular sources largest contributor to the
  emissions inventory
• Ciudad Juarez El Paso is one of the busiest
  land ports in the US borders (4th)
• Trucks must circulate through the city before
  reaching the border

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Environmental Health Perspectives.
108(7)A308-15, 2000 Jul.
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Question

• What are the health effects associated with
  traffic related emissions among asthmatic
  children in Ciudad Juarez?
• Health effects associated with traffic related to
  the border crossing
• Differential health effects in asthmatic and
  non-asthmatic children
• Is exposure associated with airway inflammation?
• Does atopy (allergic status) modify the risk?

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Methods

• Longitudinal study of school asthmatic and
  non-asthmatic children aged 6 12 years from low
  to medium SES
• Schools located in close proximity to main roads
  that contribute traffic flow to border crossings
• Asthmatics Medical diagnosis of asthma with at
  least two asthma-related ER visits in the last
  year (from IMSS)
• Gender and age matched non-asthmatics selected
  from same schools

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Study Design
100 asthmatic children 100 healthy children
38 Schools
winter
winter
summer
Follow-up for 16 weeks
Follow-up for 16 weeks

• Activities
• General questionnaire
• Daily record
• Medical/hospital visits
• Exhaled NO (8 times)
• Spirometry (8 times)
• Exhaled Breath analysis x1
• Nasal lavage x 1
• Urine for PAH x 1
• Skin testing

• Ambient data
• Local PM2.5 monitoring (48 h average)
• Elemental Carbon (Quartz)
• Passive samplers for NO2 monitoring (1 week)
• Traffic counts
• Geocoding of schools and houses
• Meteorological data

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Methods

• Analysis
• Mixed effects model, adjusting for age, gender,
  ETS, day of week, seasonality, school, BMI.
• GIS variables
• Road density, average traffic counts, distance to
  main roads
• Buffers 50m, 100m, 200m, 300m
• Exposure
• School-level (air pollutants, GIS variables)
• Subject or house-level (GIS variables)

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Study population
Variables Asthma No asthma p Atopic Non atopic p
Total 95 99 89 99
Female 31 41 34 37
Male 64 58 55 62
Age mean (SD) 9.0 (1.75) 9.0 (1.61)
Mean Weight (kg) 37.4 (18-80) 38 (19-87)
Atopy 58 37
Av. FENO 5.6 3.1 lt0.01 5.4 3.4 lt0.05
Av cough rate 0.108 0.065 lt0.01 0.083 0.083 ns
Av. Wheeze 0,021 0.002 lt0.01 0.012 0.009 ns
Av. Phlegm 0.090 0.034 lt0.01 0.061 0.057 ns
Av. Albuterol 0.083 0 lt0.01 0.039 0.033 0.07
Av. Overall symptoms 0.302 0.102 lt0.01 0.196 0.183 ns
IDR avg of questionnaire positive
responses/100 question-entries
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Pulmonary function tests
Participants Asthma No asthma
FEV1 (L) 1.68(0.51) 1.77(0.49)
FEV1 (SD) 89.6 (17) 98.1 (15)
FVC (L) 2.24 (0.70) 2.23(0.63)
FEV1 / FVC (SD) 76 (11) 83 (12)
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Asthma Severity
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Traffic and Road Data Juarez, Mexico
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Schools
Houses
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Air monitoring

• Results

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Approx 3904 Monitoring Days
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Approx 1807 Monitoring Days
Note that monitoring occurs generally in
consecutive two-day periods and, therefore,
appear in this plot to be two-week averages.
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Levels of pollutants measured at participating
schools in Ciudad Juarez, 2002 - 2003
ppb
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Exposure analysis and health effects
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Association of Log-eNO and NO2 at the schools
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Association between NO2 at schools and exhaled NO

ß ( S.E.) adjusted for age, sex, BMI, ETS,
day of wk, and season p lt 0.05
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Association of exhaled NO with PM2.5, EC, and NO2
at schools
PM2.5 EC NO2
PM2.5 EC NO2
ß ( S.E.) adjusted for age, sex, BMI, ETS,
day of wk, and season p lt 0.05
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Road length exposure (lt50m)

• Length of road within 50 meters of a subjects
  home was significantly associated with eNO levels
  in the asthmatics

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Subject level length of road (all roads) within
50 meters against Log-eNO
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Subject level roads within 50 meters by
asthma/no-asthma status
No asthma Asthma
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Subject level length of roads in 100 m by
asthma/no-asthma status
No asthma Asthma
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Association between the subject-level 50m buffer
and exhaled NO


ß ( S.E.) adjusted for age, sex, BMI, ETS,
day of wk and season p lt 0.05
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Traffic counts and exhaled NO
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Traffic counts within the 200m buffer and log-eNO
by case/control status
No asthma Asthma
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Traffic counts within the 300m buffer and log-eNO
by case/control status
No asthma Asthma
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Traffic counts within the 400m buffer and log-eNO
by case/control status
No asthma Asthma
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Traffic counts within the 500m buffer and log-eNO
by case/control status
No asthma Asthma
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Symptoms

• Road length in the 50m buffer had a marginal
  significant association (p0.06) with cough
  episodes in asthmatics, but not in
  non-asthmatics.
• No significant associations with eNO and/or
  respiratory symptoms with distance to roads at
  schools

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Conclusions

• In ciudad Juarez, NO2 exposure in schools is
  associated with increased exhaled NO
• Road-length (density) exposure within a 50 m
  buffer (home-level) is associated with increased
  exhaled NO and possibly cough only in asthmatics
  children
• No significant associations with PM2.5, or EC

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