Impact of birth season on the years of life lost from respiratory diseases in the elderly related to ambient PM2.5 exposure in Ningbo, China

Abstract

Background: Ambient fine particle (PM2.5) pollution is an important public health problem in China. Short-term ambient PM2.5 exposure is associated with increased mortality of respiratory diseases. However, few evidence was available on the effect of exposure to ambient PM2.5 on the years of life lost (YLL) from respiratory diseases in the elderly. Furthermore, birth season which is frequently applied as a proxy for environmental exposure in early life may influence the health outcome in the later life. Nevertheless, the modification effect of birth season on the relationship of PM2.5 exposure and respiratory health need to be explored. Methods: A time-stratified case-crossover design was used to analyze YLL from respiratory diseases in the elderly related to ambient PM2.5 exposure between 2013 and 2016 in Ningbo, China. The modification effect of birth season was explored by subgroup comparisons between different birth seasons. Results: Each 10 μg/m3 increase in daily ambient PM2.5 was associated with an increment of 1.61 (95% CI 0.12, 3.10) years in YLL from respiratory diseases in the elderly population. Individuals who were born in winter had significantly higher YLL from respiratory diseases associated with ambient PM2.5 exposure than those who were born in other seasons. Conclusions: Birth season which reflects the early-life PM2.5 exposure level that may influence the lung development has a potential effect on the disease burden of respiratory diseases related to ambient PM2.5 exposure in later life. The results would provide theoretical basis to protect vulnerable population defined by birth season when exploring the adverse effects of ambient PM2.5 in the respiratory health.