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Associations of health, physical activity and weight status with motorised travel and transport carbon dioxide emissions: a cross-sectional, observational study.


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Authors

Goodman, Anna 
Brand, Christian 
iConnect consortium 

Abstract

BACKGROUND: Motorised travel and associated carbon dioxide (CO₂) emissions generate substantial health costs; in the case of motorised travel, this may include contributing to rising obesity levels. Obesity has in turn been hypothesised to increase motorised travel and/or CO₂ emissions, both because heavier people may use motorised travel more and because heavier people may choose larger and less fuel-efficient cars. These hypothesised associations have not been examined empirically, however, nor has previous research examined associations with other health characteristics. Our aim was therefore to examine how and why weight status, health, and physical activity are associated with transport CO₂ emissions. METHODS: 3463 adults completed questionnaires in the baseline iConnect survey at three study sites in the UK, reporting their health, weight, height and past-week physical activity. Seven-day recall instruments were used to assess travel behaviour and, together with data on car characteristics, were used to estimate CO2 emissions. We used path analysis to examine the extent to which active travel, motorised travel and car engine size explained associations between health characteristics and CO₂ emissions. RESULTS: CO₂ emissions were higher in overweight or obese participants (multivariable standardized probit coefficients 0.16, 95% CI 0.08 to 0.25 for overweight vs. normal weight; 0.16, 95% CI 0.04 to 0.28 for obese vs. normal weight). Lower active travel and, particularly for obesity, larger car engine size explained 19-31% of this effect, but most of the effect was directly explained by greater distance travelled by motor vehicles. Walking for recreation and leisure-time physical activity were associated with higher motorised travel distance and therefore higher CO₂ emissions, while active travel was associated with lower CO₂ emissions. Poor health and illness were not independently associated with CO₂ emissions. CONCLUSIONS: Establishing the direction of causality between weight status and travel behaviour requires longitudinal data, but the association with engine size suggests that there may be at least some causal effect of obesity on CO₂ emissions. More generally, transport CO₂ emissions are associated in different ways with different health-related characteristics. These include associations between health goods and environmental harms (recreational physical activity and high emissions), indicating that environment-health 'co-benefits' cannot be assumed. Instead, attention should also be paid to identifying and mitigating potential areas of tension, for example by promoting low-carbon recreational physical activity.

Description

Keywords

Adolescent, Adult, Aged, Air Pollutants, Body Weight, Carbon Dioxide, Cross-Sectional Studies, Female, Health Status, Humans, Locomotion, Male, Middle Aged, Motor Vehicles, Surveys and Questionnaires, Young Adult

Journal Title

Environ Health

Conference Name

Journal ISSN

1476-069X
1476-069X

Volume Title

Publisher

Springer Science and Business Media LLC
Sponsorship
Economic and Social Research Council (ES/G007462/1)
Engineering and Physical Sciences Research Council (EP/G00059X/1)
Medical Research Council (MC_UU_12015/6)
Medical Research Council (MC_UU_12015/4)
Wellcome Trust (087636/Z/08/Z)
Medical Research Council (MC_U106179474)
Medical Research Council (MC_UP_1001/1)