Clinical trial NCT04695093: Children's Health in London and Luton (CHILL)
Official title: Investigating the Impact of London's Ultra Low Emission Zone on Children's Respiratory Health
Study type: OBSERVATIONAL
Overall status: ACTIVE_NOT_RECRUITING
Conditions: Pollution; Exposure
Respiratory Disease
Child Development
Keywords: respiratory disease
Lead sponsor: Queen Mary University of London
Sponsor class: OTHER
Collaborators: name: King's College London
name: University of Edinburgh
name: University of Bedfordshire
name: University of Cambridge
name: University of Southern California
First posted: 2021-01-05
Enrollment: 3312
Sex: ALL
Minimum age (years): 9
Maximum age (years): 9
Standard ages: CHILD
Accepts healthy volunteers: yes
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Children aged 6-9 yrs old, recruited in 40 London primary schools (years 2, 3, 4) within the Central London ULEZ area

and

Children aged 6-9 yrs old, recruited in 40 Luton primary schools (years 2, 3 4).

Brief summary: Investigating the impact of London's Ultra Low Emission Zone on children's respiratory health

Detailed description: Strong evidence links urban air pollution to restrictions in children's lung growth and development and other adverse effects, including increases in respiratory and allergy symptoms, respiratory infections, asthma, and health care use. Effective interventions are urgently needed that reduce air pollution and improve child health. Low Emission Zones (LEZ) are becoming widespread but are expensive to implement and of unproven health benefit. London has some of the worst air pollution in Europe. London's Ultra Low Emission Zone (ULEZ) is the central component of London's air quality strategy. Its implementation provides a unique opportunity to test the impact of a city-wide LEZ on children's health.

The intervention:

The ULEZ is an area within which all vehicles must meet exhaust emission standards or pay a daily charge to travel. It will be implemented and paid for by Transport for London. Starting in 2019, the ULEZ will initially cover London's central Congestion Charging Zone, an area bounded by the London Inner Ring Road, that includes the City of London plus adjacent areas of eight radially adjoining Boroughs. It is projected to deliver for central London by 2020 emission reductions of -49% for NOx; - 47% for NO2; and -11% for PM10. Subject to consultation, the ULEZ will subsequently extend to include an inner London area (within London's North and South Circular roads), and a London-wide area, for heavy vehicles only.

Questions:

1. What is the impact of the ULEZ on children's lung growth (the primary outcome)?
2. What is the impact of the ULEZ on secondary outcomes, including self-reported symptoms, respiratory infection, health care use and costs?
3. Does the ULEZ reduce health inequalities? 4) Is the ULEZ good value for money?

Study design:

Quasi-experimental study using a parallel cohort design. Population: 1520 children aged 6-9 yrs old, recruited in 26 London primary schools (school years 2, 3 and 4) in London's Central Ultra Low Emission Zone. Intervention: Ultra Low Emission Zone Comparison: 1520 children aged 6-9 yrs old, recruited in 26 primary schools (school years 2, 3 and 4) in Luton, matched for ethnicity, deprivation and baseline air quality.

Outcome: PRIMARY: Lung function growth (post-bronchodilator forced expiratory volume in one second (FEV1) measured by high quality spirometry at sequential annual school visits over four years. SECONDARY: Forced vital capacity (FVC), exhaled nitric oxide (FeNO), quality of life, respiratory infections, health care use, health costs.

Sample size:

To detect a 15ml/year FEV1 difference between central and outer London cohorts at 90% power and 0.05 significance requires children in each cohort, inflated to allow for clustering effect of schools, spirometry success, child and school attrition, and pre-specified sub group analyses, giving a total of 3120 children (60 children from 26 schools in each cohort).

Duration: 6 years Air quality data: Modeled exposures by London Air Quality Network Data management: NIHR accredited Pragmatic Clinical Trials Unit Analysis: Interaction analysis controlling for effect modifiers (eg passive smoke; ethnicity); health economic cost consequence analysis.

Eligibility criteria: Inclusion Criteria:

* Inclusion criteria for schools:

  * Primary schools within, or with catchment areas that include, the Central London ULEZ.
  * Primary schools within the Borough of Luton and town of Dunstable.
  * State or independent sectors.

Inclusion criteria for children:

• Children attending a study school, in years 2, 3, or 4, at study inception.

Exclusion Criteria:

* Exclusion criteria for schools:

  * Schools that are not primary schools within the above boundaries.

Exclusion criteria for children:

* Children with learning or physical disabilities sufficient for them to be unable to give informed assent to the study, or to carry out study procedures.
* Children with major lung disease (not including asthma).

Primary outcomes:
measure: Lung function growth as change in forced expiratory volume in one second (FEV1) per year
timeFrame: Four years, 2018 -2021
Secondary outcomes:
measure: Air quality, nitrogen dioxide (NO2) concentration derived from the the KCLUrban dispersion model
timeFrame: Four years, 2018 -2021
measure: Air quality, oxides of nitrogen (NOx) concentration derived from the KCLUrban dispersion model
timeFrame: Four years, 2018 -2021
measure: Air quality, particulate matter diameter <2.5microns derived from the KCLUrban dispersion model
timeFrame: Four years, 2018 -2021
measure: Air quality, particulate matter diameter <2.5microns derived from the KCLUrban dispersion model
timeFrame: Four years, 2018 -2021
measure: Lung capacity as FVC (forced vital capacity)
timeFrame: Four years, 2018 -2021
measure: Annual prevalence of wheeze, as proportion (%) of respondents reporting wheeze
timeFrame: Four years, 2018 -2021
measure: Annual prevalence of eczema, as proportion (%) of respondents reporting eczema
timeFrame: Four years, 2018 -2021
measure: Annual prevalence of rhinitis, as proportion (%) of respondents reporting rhinitis
timeFrame: Four years, 2018 -2021
measure: Annual prevalence/participant of upper respiratory tract infections
timeFrame: Four years, 2018 -2021
measure: Annual prevalence/participant of lower respiratory tract infections
timeFrame: Four years, 2018 -2021
measure: Physical activity, as Percentage time in Moderate to Vigorous Physical activity per participant (MVPA)
timeFrame: Four years, 2018 -2021
measure: Annual health care use per participant
timeFrame: Four years, 2018 -2021
measure: Annual health care costs per participant
timeFrame: Four years, 2018 -2021
measure: Cognitive function as average Movement Time in seconds (MT) on the Clinical Kinematic Assessment Test
timeFrame: Three years, 2019 -2021
measure: Child Quality of Life as score out of 40
timeFrame: Four years, 2018 -2021
Other outcomes:
Locations:
city: London
country: United Kingdom
facility: Queen Mary University of London
Study officials:
affiliation: Queen Mary University of London
name: Mays Jawad, PhD
role: STUDY_DIRECTOR
References: