Long-Term Greenspace Exposure and Progression of Arterial Stiffness: The Whitehall II Cohort Study

Background: Arterial stiffness, and its progression with age, is an important indicator of cardiovascular aging. Greenspace exposure may protect against arterial stiffness by promoting physical activity, fostering social cohesion, and reducing stress and exposure to air pollution and noise.

Objectives: The aim of this study was to investigate the association of long-term exposure to outdoor greenspace with arterial stiffness and its progression over time.

Methods: This prospective cohort study was based on 4,349 participants (55-83 years of age) of the Whitehall II Study, United Kingdom. Arterial stiffness was assessed in two medical examinations (2007-2009 and 2012-2013) by measuring the carotid-femoral pulse wave velocity (cf-PWV). Residential surrounding greenspace was characterized using satellite-based indices of greenspace including normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and vegetation continuous fields (VCF) across buffers of 500 and $\mathrm{1,000}m$ surrounding the participants' residential locations at each follow-up. The association between the greenspace indicators and baseline cf-PWV and 4-year progression of cf-PWV was assessed using linear mixed-effects models with the participant as a random effect, controlling for demographic, lifestyle, and (individual and area) socioeconomic factors.

Results: No statistically significant associations were observed between residential surrounding greenspace and baseline or 4-y progression of cf-PWV; interquartile range (IQR) increases in NDVI, EVI, and VCF in the $500\text{-m}$ buffer were associated with $-0.04m/s$ [95% confidence interval (CI): $-0.12$, 0.04], $-0.03m/s$ (95% CI: $-0.10$, 0.05), and $-0.02m/s$ (95% CI: $-0.08$, 0.04) in baseline cf-PWV and $0.06m/s$ (95% CI: $-0.02$, 0.14), $0.05m/s$ (95% CI: $-0.03$, 0.14), and $0.00m/s$ (95% CI: $-0.09$, 0.09) in 4-y progression in cf-PWV, respectively. The associations were similar when using $\mathrm{1,000}\text{-m}$ buffers.

Conclusions: We did not observe any consistent association between residential surrounding greenspace and arterial stiffness. https://doi.org/10.1289/EHP6159.