Residential proximity to greenness mitigates the hemodynamic effects of ambient air pollution

• Published in: American journal of physiology. Heart and circulatory physiology 2021-03, Vol.320 (3), p.H1102-H1111
• Main Authors: Riggs, Daniel W, Yeager, Ray, Conklin, Daniel J, DeJarnett, Natasha, Keith, Rachel J, DeFilippis, Andrew P, Rai, Shesh N, Bhatnagar, Aruni
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Air Pollutants - adverse effects; Air pollution; Air Pollution - adverse effects; Air pollution effects; Air pollution measurements; Aorta; Arterial Pressure; Augmentation; Blood pressure; Cardiovascular diseases; Cardiovascular Diseases - etiology; Cardiovascular Diseases - physiopathology; Cardiovascular Diseases - prevention & control; City Planning; Environmental Exposure - adverse effects; Female; Health risks; Heart diseases; Hemodynamics; Humans; Hypertension; Kentucky; Male; Middle Aged; Normalized difference vegetative index; Ozone; Ozone - adverse effects; Particulate matter; Particulate Matter - adverse effects; Pollutants; Pollution effects; Protective Factors; Proximity; Regression analysis; Regression models; Residence Characteristics; Risk Assessment; Risk Factors; Stiffness; Systolic pressure; Urban Health; Urbanization; Vascular Stiffness; Young Adult
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/AJPHEART.00689.2020

Residential proximity to greenness is associated with a lower risk of cardiovascular disease (CVD) and all-cause mortality. However, it is unclear whether the beneficial effects of greenness are linked to a reduction in the effects of ambient air pollutants. We measured arterial stiffness in 73 participants with moderate to high CVD risk. Average levels of ambient PM and ozone were calculated from local monitoring stations. Residential greenness was estimated using satellite-derived normalized difference vegetation index (NDVI) for a 200-m and 1-km radius around each participant's home. Participants were 51% female, average age of 52 yr, and 79% had diagnosed hypertension. In multiple linear regression models, residential NDVI was negatively associated with augmentation index (-3.8% per 0.1 NDVI). Ambient levels of PM [per interquartile range (IQR) of 6.9 μg/m ] were positively associated with augmentation pressure (3.1 mmHg), pulse pressure (5.9 mmHg), and aortic systolic pressure (8.1 mmHg). Ozone (per IQR of 0.03 ppm) was positively associated with augmentation index (5.5%), augmentation pressure (3.1 mmHg), and aortic systolic pressure (10 mmHg). In areas of low greenness, both PM and ozone were positively associated with pulse pressure. Additionally, ozone was positively associated with augmentation pressure and systolic blood pressure. However, in areas of high greenness, there was no significant association between indices of arterial stiffness with either PM or ozone. Residential proximity to greenness is associated with lower values of arterial stiffness. Residential greenness may mitigate the adverse effects of PM and ozone on arterial stiffness. Previous studies have linked proximity to green spaces with lower cardiovascular disease risk. However, the mechanisms underlying the salutary effects of green areas are not known. In our study of participants at risk of cardiovascular disease, we found that arterial stiffness was positively associated with short-term exposure to PM , PM , and ozone and inversely associated with greenness. The association between pollution and arterial stiffness was attenuated in areas of high greenness, suggesting that living green neighborhoods can lessen the adverse cardiovascular effects of air pollution.