2. 15 January, 2019

3. Early life exposure to traffic-related air pollution and lung function in adolescense. A birth-cohort study
Erica S Schultz
MD, PhD-student
J.Hallberg, T.Bellander, A.Bergström, M.Bottai,
O.Gruzieva, P.Thunqvist, M.Wickman,
G.Pershagen, E.Melén

4. Background
Lung function is an easily measurable and reliable indicator of the physiological state of lungs and airways
Lung function also predicts mortality in the general population
Studies indicate that adverse long-term effects of traffic related air pollution occur on lung function growth in children
Possible pathway: Air Pollutants → Free radicals → Oxidative stress → Airway inflammation → Lung function impairment
Lung function is an easily measurable and reliable indicator of the physiological state of lungs and airways.
Lung function also predicts mortality in the general population, even among non-smokers with only modesdtly reduced lung function.
Evidence that adverse long-term effects of Traffic Related Air Pollution (TRAP) occur on lung function growth in children
Possible pathway: Air Pollutants → Free radicals → Oxidative stress → Airway inflammation → Lung function impairment
Ref 1. Wilk Genet epidemiology 2000, ref2, Schunrmann HJ, Chest 2000, ref3, Gauderman Nejm 2004 or Lancet 2007
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5. Key issue
Time periods of exposure and susceptibility
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6. AJRCCM 2012;186(12):
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7. Aims
To investigate the effect of individual long term exposure to air pollution from traffic on children’s lung function at 16 yrs of age
To clarify if critical time periods of exposure and susceptible populations can be identified

8. Exposure questionnaire 4,089 - 100%
Material and Methods
Exposure questionnaire 4, %
8 year follow up
Questionnaire %
Spirometry %
Blood %
1 year questionnaire
3, %
12 year questionnaire
2900 – 71%
2 year questionnaire
3, %
16 year follow up
Questionnaire %
Spirometry %
Blood %
4 year follow up
Questionnaire %
Dust %
PEF %
Blood %
My study population comprise of study participants with full set of confounders mainly derivied from Exposure questionnaire (0 years), spirometry data from 16 years as well as all air pollution exposure time periods available.
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9. Air pollution Assessment
Address history
Geocoding
NOₓ from traffic
On this slide, I am going to try and explain the method of this historical air pollution assessment.
First, we used data on the residential history of each subject, which they reported in the questionnaire. Then we translated all addresses into geographical coordinates (using GIS and a regional address database.)
These coordinates were then linked to dispersion models for different air pollutants, and they describe the geographical distribution of air pollution in different geographical resolutions, down to resolutions of 25 m grids.
These dispersion models are based on historical emission databases Then, we did a linear interpolation for the years between these emission databases for each address, and we finally end up with an individual level of different air pollutants for each subject in the study.
Individual air pollution exposure for Nox and PM10 up to 8 years of age is available for more than 4000 children.
Nox (NO2 NO) is directly emitted from fuel combustion. Reduced since introduction of cleaning techniques in power plant and catalytic converters in petrol cars. (Historical emission databases for NOx were available for the years 1990, 1995, 2000, ,2006 and 2010)
Pm10, particles equal or less than 10 um in diameter. Largest mass is derived from organc or inorganic fragments in dust of from road and vehicle wear. (fine particles are emitted from combustion processes of fossil fuel.
2008
Dispersion modelling based
on emission databases
Median NOx = 17 ɥg/m³
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10. Exposure time windows First year of life 1-4 years 4-8 years
12-16 is upcoming
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11. Results FEV1 at 16 years in relation to traffic-NOx exposure in different time periods of life
First year of life
1-4 years
4-8 years
8-12 years
Adjusted for age, gender, height, heritability of allergic diseases, smoking, and municipality.
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12. FEV1 at 16 years in relation to traffic-NOx exposure in the first year of life
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13. Association between first year of life exposure to NOx and FEV1 less then 80% of predicted
OR 2.3
(95% CI 0.9 to 6.5).
Associations were also suggested between first year of life exposure to NOx and clinically important lung function deficits of less than 80% of predicted FEV1 with an odds ratio of 2.3 (95% CI 0.9 to 6.5).
For 5% lowest percentile of zscore FEV1 the corresponding odds ratio is1.8 (95%CI 0.8 to 4.2)
*Prediction based on age,height,gender and weight and interactions of gender with
age, height and weight.
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14. Conclusion
Our results indicate that exposure to traffic-related air pollution during infancy negatively affects lung function in adolescents at 16 years of age.
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15. Acknowledgements
We thank all participating children and parents in BAMSE
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16. Thank you! Erica S Schultz MD, PhD-student
Unit of Environmental Epidemiology
Institute of Environmental Medicine
Karolinska Institutet