Table 1 Description of potential individual, socio-cultural and environmental exposure variables

Individual

Parent education

Collected in 14 categories then coded as: low, medium, high.

-

Child’s BMI

Children’s height and weight were measured and body mass index computed (weight/height ²), which were used to classify children as normal weight, overweight or obese based on internationally recognised cut offs.

[23]

Socio-cultural

Frequency of children’s non school walking or cycling (p)

Frequency of walking or cycling to either a sports centre, parks, shops or friend’s home using response categories of ‘never’, ‘none within walking or cycling distance’ and four frequency categories ranging from ‘less than once a week’ to ‘6 or more days a week’. Coded as: not walking or cycling to any non-school destination (‘never’ or ‘none within walking or cycling distance’) or any frequency (all other responses).

-

Convenience of the car (p)

Coded as strongly agree and agree and neither, disagree, strongly disagree.

[20]

Parents are around to take their child to school (p)

Coded as strongly agree and agree and neither, disagree, strongly disagree.

Rules (c)

Sum of responses (‘yes’ or ‘no’) to two items on rules for independent mobility (‘I always have to tell my parents where I am going’ and ‘If I am going out I always have to be back by a certain time’). Score range: 0-2.

-

Peer and parental support (c)

Sum of responses (‘yes’ or ‘no’) to two items on friends and parents encouragement to walk or cycle to school Score range: 0–2.

-

Environment

Perceptions of the neighbourhood environment

Social cohesion and trust in their neighbourhood (p)

Sum of responses (‘strongly agree’ to ‘strongly disagree’) to seven items regarding social cohesion and trust in neighbourhood*. Summary scores were split into tertiles.

[24]

Physical neighbourhood environment (p)

Sum of responses (‘strongly agree’ to ‘strongly disagree’) to 24-item version of the adapted Neighbourhood Environment Walkability Scale (ANEWS). Summary scores were split into tertiles*.

[20]

Physical neighbourhood environment (p)

Sum of responses (‘strongly agree’ to ‘strongly disagree’) to four statements about the characteristics of the route between home and school (the presence of pavements, cycle-paths, concern about dangerous traffic and concern that something would happen to their child along the route to school). * Summary scores were created and scores dichotomised into ‘low’ or ‘high’ based on the median responses.

[20]

Safety to play in neighbourhood (c)

Child-rated safety to walk or play in the neighbourhood during the day, using ‘yes’ or ‘no’ response categories.

-

Objective measures of the neighbourhood environment

Road density

Total road lengths divided by neighbourhood area. Scores dichotomised into ‘low’ or ‘high’.

[21, 25]

Proportion of primary roads

Length of primary (A) roads divided by total road length. Scores dichotomised into ‘low’ or ‘high’.

[21, 25]

Streetlights per km of roads

Number of street lights divided by total road length. Scores dichotomised into ‘low’ or ‘high’.

[21, 25]

Effective walkable area

Total neighbourhood area (the area that can be reached via the street network within 800 m from the home) by the potential walkable area (the area generated using a circular buffer with a radius of 800 m from the home). Scores dichotomised into ‘low’ or ‘high’.

[21, 25]

Connected node ratio

Number of junctions divided by number of junctions and cul-de-sacs. Scores dichotomised into ‘low’ or ‘high’.

[21, 25]

Junction density

Number of junctions divided by total neighbourhood area. Scores dichotomised into ‘low’ or ‘high’.

[21, 25]

Land-use mix

Proportion of each land use¹ squared and summed. This score is also known as the Herfindahl-Hirschman Index. Scores dichotomised into ‘low’ or ‘high’.

[21, 25]

Deprivation

Index of multiple deprivation scores for neighbourhood of home address. Scores split into quartiles.

[21, 25]

Urban–rural status

Urban rural status of home address. Classification of Bibby and Shepherd (2006) and coded into: urban, town and fringe and other.

[21, 25]

Objective measures of the route environment

Distance between home and school

Shortest route between home address and nearest school access point. Coded as more than 2 km, 1-2 km or less than 1 km.

[21, 25]

Streetlights per km of route

Streetlights within 100 m of route divided by route length. Scores dichotomised into ‘low’ or ‘high’.

[21, 25]

Presence of a main road en route

Presence of primary (A) road as part of route. Coded as ‘yes’ or ‘no’.

[21, 25]

Route length ratio

Route length divided by the straight line distance between the home and school. Coded as: indirect route (≥1.6) or direct route (<1.6) This is sometimes known as the route directness index.

[21, 25, 26]

Land-use mix along the route

Percentage of each land use¹ within 100 m of route squared and summed. Scores dichotomised into ‘low’ or ‘high’. This score is also known as the Herfindahl–Hirschman index.

[21]

Route within an urban area

Percentage of route which passes through urban area. Coded as: ‘yes’ (route is completely within an urban area) or ‘no’ (route not completely within an urban area).

[21]

Objective measures of the school environment

School travel plan

Head teachers reported whether their school had a school travel plan (‘yes’ or ‘no’) (a formal document, which identifies ways of encouraging more children to walk, cycle or use public transport to get to school).

[27]

Held walk to school campaigns

Head teachers reported whether they held walk to school campaigns (including walk to school days or weeks) (‘yes’ or ‘no’).

[27]

Walking provision

School audit assessment of the facilities within and surrounding the school for walking. Scores dichotomised into quartiles.

[27]

Cycling provision

School audit assessment of the facilities within and surrounding the school for cycling. Scores dichotomised into quartiles.

[27]