Exposure to environmental noise and air pollution and cardio-respiratory outcomes in the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort and the UK Biobank

Traffic noise and ambient air pollution are the leading environmental risk factors for public health in the European region. This thesis explores how these exposures affect trajectories of cardiovascular and respiratory risk factors from childhood to early adulthood.

Objectives: I) assess whether ambient air pollution confounds the association between traffic noise and cardiovascular health; II) evaluate associations between road traffic noise (RTN) and blood pressure in childhood to early-adulthood; III) evaluate associations between RTN and cIMT in younger and older adults; IV) evaluate associations between prenatal and early-life air pollution exposure and lung function trajectories throughout childhood to early-adulthood.

Results: I) A systematic review of 52 publications evaluating traffic noise and cardiovascular outcomes that considered air pollution confounding or interaction, suggested noise associations are independent of air pollution.

II) RTN was associated with small but statistically significant increases in the annual change in blood pressure during adolescence, using linear spline models to assess associations between RTN exposure and blood pressure trajectories between 3-24 years in the ALSPAC cohort.

III) Cross-sectional associations between RTN and cIMT were assessed in ~650 participants aged 24-years in ALSPAC and ~48,000 older adults in the UKBiobank. Generalised linear regression models were non-statistically significant in ALSPAC, but showed a significant increase of for highest RTN (Lden) exposure in UKBiobank.

III) Prenatal and early life air pollution exposures were associated with a small but statistically significant reduction in annual lung function growth in ages 8-24 years, with larger effect sizes up to aged 15 years, using mixed-effects linear models in ~3700 ALSPAC cohort participants.

This study found evidence that outdoor air and noise pollution levels affect development of the respiratory and cardiovascular system with greatest impacts in adolescence, the time of fastest growth. These long-lasting impacts of childhood environmental pollution exposure have implications for exposure reduction policies.