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Air pollution

Non-freeway NOx tracks children's BMI growth

Jerrett M, McConnell R, Wolch J, et al. · Environmental health : a global access science source · 2014

Open access · cc by · source: Europe PMC

In 4,550 Southern California children, non-freeway NOx associated with BMI at age 10 and 4-year growth; freeway NOx and near-road traffic density were weaker after confounding control.

Study at a glance

Design
Cohort — Longitudinal multilevel BMI growth models vs traffic density and CALINE-like NOx
N
N=4550 · 4,550 children in 13 Southern California communities
Population
Schoolchildren in Southern California communities
Outcome
BMI level and 4-year growth related to non-freeway vs freeway NOx and near-road traffic

Structured fields used in claim comparison tables when every cited study has a complete layer.

Key findings

Mean age 6.6 years; BMI rose ~2.6 units over 5 years. Traffic within 150 m was confounded (especially Spanish questionnaire). Non-freeway NOx stayed positively associated with BMI and slope; freeway NOx was not.

Methodology

Multilevel growth models of measured BMI in a school cohort assigned baseline traffic density and CALINE-like freeway vs non-freeway NOx, adjusting for SES, smoking, greenness, fast food, and street connectivity.

Limitations

Observational BMI growth is not a randomized pollution trial; diet was not fully measured, and baseline-address exposure misses residential mobility.

How this study connects

Role on claims

Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.

  • SupportsCohort Studymethod

    A school cohort's multilevel BMI growth models (mean age 6.6 years; BMI rose ~2.6 units over 5 years) found non-freeway NOₓ still positively associated with BMI level and slope after SES, smoking, greenness, fast food and street-connectivity adjustment, while freeway NOₓ was not. Traffic density within 150 m was confounded, especially on the Spanish questionnaire.

    Evidence for the claim as stated.

  • SupportsCohort Studymethod

    Traffic signals split by source and by how hard confounding is controlled. Children's BMI tracked non-freeway NOₓ but not freeway NOₓ, and near-road traffic density was confounded. In the Danish cancer screen, cervical and brain associations remained after adjustment while many smoking-related IRRs shrank, and the analysis was a 20-cancer screen without HPV data for cervix.

    Evidence for the claim as stated.

  • SupportsMixed-Effects Modelmethod

    Multilevel growth models of measured BMI in a school cohort (mean age 6.6 years; BMI rose ~2.6 units over 5 years) assigned baseline traffic density and CALINE-like freeway versus non-freeway NOₓ, adjusting for SES, smoking, greenness, fast food and street connectivity. Traffic within 150 m was confounded (especially the Spanish questionnaire). Non-freeway NOₓ stayed positively associated with BMI level and slope; freeway NOₓ was not.

    Evidence for the claim as stated.

  • SupportsMixed-Effects Modelmethod

    Mixed-effects and adjacent hierarchical papers here are not one invasive-species result. Children's BMI growth is a traffic-pollution question (non-freeway NOₓ associated; freeway NOₓ not). Abisko space-for-time finds SOC falling from 9.01 to 4.51 kg m⁻² heath to forest as a shrub-expansion analogue. Šumava tree rings track beech versus spruce under shifting air chemistry in 35 trees. The brown-trout PVA is a suppression forecast (QE in 5.7–6.3 years; 29% if age-0 methods are skipped), not a mixed model of field counts proving those rates. The method label mixes four questions.

    Evidence for the claim as stated.

Open questions

Tensions this paper is part of

From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.

  • Scope difference — different assays, populations, or outcomes

    SupportsCohort Study

    Traffic signals split by source and by how hard confounding is controlled. Children's BMI tracked non-freeway NOₓ but not freeway NOₓ, and near-road traffic density was confounded. In the Danish cancer screen, cervical and brain associations remained after adjustment while many smoking-related IRRs shrank, and the analysis was a 20-cancer screen without HPV data for cervix.

  • Scope difference — different assays, populations, or outcomes

    Mixed-effects and adjacent hierarchical papers here are not one invasive-species result. Children's BMI growth is a traffic-pollution question (non-freeway NOₓ associated; freeway NOₓ not). Abisko space-for-time finds SOC falling from 9.01 to 4.51 kg m⁻² heath to forest as a shrub-expansion analogue. Šumava tree rings track beech versus spruce under shifting air chemistry in 35 trees. The brown-trout PVA is a suppression forecast (QE in 5.7–6.3 years; 29% if age-0 methods are skipped), not a mixed model of field counts proving those rates. The method label mixes four questions.

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Same topic cluster — not a recommendation engine.