Cardiovascular and renal effects of long-term particle exposure

Abstract

Background and aims Long-term particle exposure is a major risk factor for cardiovascular disease, claiming millions of lives annually. However, it remains uncertain if atherosclerosis mediates the cardiovascular effects of particle exposure. Similarly, the impact of ambient and occupational particle exposure on the kidneys is not sufficiently understood. This thesis explores how particle exposure is associated with atherosclerosis, renal function, and chronic kidney disease. Methods Ambient particle exposure was assessed in the general population using large air pollution models validated against monitoring station data. Occupational particle exposure in a cohort of construction workers was estimated via a job-exposure matrix developed by experienced occupational hygienists. Coronary and carotid atherosclerosis, as well as cardiovascular biomarkers and estimated renal function, were measured cross-sectionally and analysed using multivariable-adjusted robust Poisson, ordinal logistic, and linear regression models. Incident chronic kidney disease was identified longitudinally from healthcare registers and analysed using multivariable-adjusted Cox proportional hazard models. Results Fine particle exposure appeared to be associated with more rupture-prone non-calcified plaques, but not with total coronary atherosclerosis, and with elevated levels of a biomarker of plaque vulnerability. Traffic-related pollutants were suggestively linked to a higher prevalence of carotid plaques and greater carotid plaque area. Both ambient and occupational particle exposure were associated with an increased risk of chronic kidney disease. Ambient particle exposure was associated with slight hyperfiltration, which may be due to chance or an early sign of renal stress. Conclusions These results highlight plaque vulnerability, rather than calcification, as a mechanism linking long-term low-level particle exposure to cardiovascular disease. They also underscore the importance of considering chronic kidney disease in health impact assessments of particle exposure. From a policy perspective, these findings support that stricter regulations of particle exposure in both ambient and occupational settings would have substantial benefits for public health, even at low exposure levels.