Background: There is a scarcity of robust evidence that has examined how exposure to air pollution may change over the life course. We attempt to combine innovations in spatial data science and historical environmental data with robust birth cohort data to examine inequity in exposure to air pollution over the life course.
Methods: Data were gathered from the Christchurch Health and Development Study (CHDS), a birth cohort from Christchurch, New Zealand (NZ) established in 1977 (n=1,265). Air pollution estimates corresponded to birth cohort data from birth in 1977 to age 40 years in 2017. The study has 80% power to detect a correlation of .09 or greater between a continuous measure of exposure and outcome. Mixed models were used examined the association between sociodemographic characteristics representing both socioeconomic status and ethnicity with air pollution exposure.
Results: First, our study demonstrates the feasibility of using historical air pollution estimates by successfully relating them to a birth cohort study. Second, our findings, which should be considered within an environmental justice framework generally, indicated significant inequities in air pollution exposure by both socioeconomic status and ethnicity. Specifically, those cohort members born into the most disadvantaged families (based on paternal occupation at birth) had both the highest annual average and winter peak exposure to air pollution. Preliminary results suggest this pattern may be most pronounced for Māori.
Conclusion: We extend evidence by linking historical air pollution data to robust data from birth cohort to examine long-term changes in exposure to air pollution over the life course. Future research should now explore how such inequities in air pollution exposure are related to health outcomes over the life course in particular mental health which has received less attention than other physical health outcomes such as respiratory conditions.