Vitamin D has been getting a lot of attention during COVID-19. A recent study found more than 82.2% of coronavirus patients hospitalized in Spain were deficient in the vitamin, while only 47.2% of healthy people had low levels of the sunshine vitamin.

According to Insider, the study authors also discovered a correlation between patients with low levels of vitamin D and hypertension, heart disease, raised markers of inflammation, and longer hospital stays. In general, men had lower levels of vitamin D than women.

The researchers, from the University of Cantabria, in Santander, Spain, said their findings point to identifying and treating vitamin D deficiency in those most at risk for COVID-19, "such as the elderly, patients with comorbidities, and nursing home residents, who are the main target population for the COVID-19," according to their news release.

An earlier study, also conducted in Spain, found increasing levels of D3, a more absorbable version of the vitamin, helped severely sick patients with COVID-19 improve their outcomes. Previous research has indicated vitamin D plays a role in modulating acute respiratory infections by preventing white blood cells from overreacting to the infection and releasing too many inflammatory cytokines.

Scientists also found people in countries that have the highest mortality rates from COVID-19 like Italy and Spain, also have the lowest levels of vitamin D. Conversely, the highest levels of vitamin D were found in countries such as the Scandinavian nations, with the lowest mortality rates, according to Science Daily.