Sunny areas are associated with fewer Covid-19 deaths, an observational study suggests.
Increased exposure to the sun̵
Researchers from the University of Edinburgh compared all recorded deaths from Covid-19 in the continental United States from January to April 2020 with UV levels for 2,474 U.S. counties in the same time period.
The study found that people living in areas with the highest level of exposure to UVA rays – which make up 95 percent of the sun’s UV light – had a lower risk of dying from Covid-19 compared to those with lower levels. The analysis was repeated in England and Italy with the same results.
The researchers took into account factors known to be associated with increased exposure to the virus and risk of death such as age, ethnicity, socioeconomic status, population density, air pollution, temperature and levels of infection in local areas.
The observed reduction in the risk of death from Covid-19 could not be explained by higher levels of vitamin D, experts said. Only areas with insufficient levels of UVB to produce significant vitamin D in the body were included in the study.
One explanation for the lower number of deaths that researchers are following up on is that exposure to sunlight causes the skin to release nitric oxide. This may reduce SARS Coronavirus2 – the cause of Covid-19 – to replicate, as found in some laboratory studies.
Previous studies from the same group have shown that increased sunlight exposure is associated with improved cardiovascular health with lower blood pressure and fewer heart attacks. Since heart disease is a known risk factor for dying from Covid-19, this may also explain recent findings.
The team says that due to the observational nature of the study, it is not possible to determine cause and effect. However, it can lead to interventions that can be tested as potential treatments.
The paper has been published in British Journal of Dermatology, an official publication of the British Association of Dermatologists.
Reference: April 8, 2021, British Journal of Dermatology.
DOI: 10.1111 / bjd.20093
Dr. Richard Weller, corresponding author, consultant dermatologist and reader at the University of Edinburgh, said: “There is still so much we do not understand about Covid-19, which has resulted in so many deaths worldwide. These early results open up for sunlight exposure as a way to reduce the risk of death. “
Professor Chris Dibben, Chair of Health Geography at the University of Edinburgh and co-author, said: “The relationship between Covid-19 mortality, season and latitude has been quite striking, here we offer an alternative explanation for this phenomenon.”