Residential greenness may protect against post-COVID ischaemic heart disease

Exposure to residential greenness in COVID-19 survivors appears to reduce the risk of chronic ischaemic heart disease but not that of acute coronary events, as reported in a cohort study from South Korea.

Researchers used the Korea Disease Control and Prevention Agency–COVID‐19–National Health Insurance Service database and looked at individuals aged 19 years or older who had confirmed SARS‐CoV‐2 infection.

National Health Insurance Service health screening and claims data were linked to Korea Disease Control and Prevention Agency surveillance records. Normalized difference vegetation index (NDVI; low 0.2 to <0.4, moderate 0.4 to <0.6, high 0.6) was used to measure residential greenness.

A first diagnosis of coronary artery disease (acute coronary syndrome or chronic ischaemic heart disease) within 30 days after infection was the primary outcome. Inverse probability of treatment weighting and weighted Cox models were used in the analyses.

A total of 3,097,179 individuals (61.4 percent men) were included in the study. NVDI exposure was classified as low in 25.3 percent of participants, moderate in 59.7 percent, and high in 15 percent.

NDVI had a null effect on the risk of acute coronary syndrome. But for the risk of chronic ischaemic heart disease, a higher NDVI was associated with a protective effect (moderate NDVI: adjusted hazard ratio [aHR], 0.86, 95 percent confidence interval [CI], 0.84–0.88; moderate NDVI: aHR, 0.82, 95 percent CI, 0.80–0.84).

The association was more pronounced in moderate to severe COVID‐19, vaccinated individuals, males, and younger individuals.

The findings suggest a potential role of residential greenness in long‐term cardiovascular health after SARS‐CoV‐2 infection.