Link between Vitamin D Deficiency and COVID-19 Mortality Deepens: Study
Thu, February 2, 2023

Link between Vitamin D Deficiency and COVID-19 Mortality Deepens: Study


A new study suggests an association between COVID-19 deaths and deficiency of vitamin D. While the cause and effect between the two cannot be determined yet, this new research adds to the growing evidence revealed by previous studies.

The latest evidence of the link between vitamin D deficiency and COVID-19 mortality was revealed by researchers in Indonesia. Their findings suggested that the majority of deaths in the study cohort exhibited signs of vitamin D deficiency. Even after accounting for other factors, the association remained strong in the mortality of COVID-19 patients. They published the results in the Social Science Research Network, an international journal for research.

Low Vitamin D May Lead to Higher Risk of COVID-19 Mortality

While the world fights the COVID-19 pandemic, there are research groups that continue to work round the clock to unravel the disease's mysteries. If unlocked, insights can help develop better treatments before the vaccine becomes available. Some studies have found evidence concerning organ damage, others have uncovered hints of potential resistance after recovery, and a few are focused on other physiological factors.

In Indonesia, a group of researchers published a new paper to show the strong relationship between vitamin D deficiency and COVID-19 deaths. Although they were unable to determine the cause and effect, their research might encourage others to conduct further studies. If an explanation could be found, boosting vitamin D in those with the deficiency might be a way to reduce mortality.

In the study, researchers explained that vitamin D has been proven to enhance cellular immunity and modulate adaptive immunity, the other line of defense of the immune system involving B and T cells. The capability of vitamin D to assist the immune system made its way through many researchers who proposed its supplementation among patients, in hopes of reducing the severity of COVID-19. These researchers were somehow convinced of the vitamin's role in fighting the novel disease due to documented cases in Southeast Asia.

Before this research, some studies were published earlier to present the unusual relationship between the disease and the vitamin. According to Psychology Today, a US-based magazine, Mark Alipio of the Davao Doctors College in the Philippines observed the relationship as well. Alipio discovered that patients with mild symptoms of COVID-19 had normal levels of vitamin D, compared to those who experienced moderate or severe symptoms. Specifically, normal vitamin D levels could increase the chance of mild symptoms by about 19.6 times, which would be significant to everyone who has COVID-19.

Prabowo Raharusun, the lead of the Indonesian research group, also reached the same conclusion in examining 780 laboratory-confirmed cases of COVID-19. Their examination unveiled clinical evidence to support Alipio's findings and findings from other related studies. A decrease in the serum 25(OH)D level in the human body could result in worse clinical outcomes from COVID-19. As a reference, serum 25(OH)D described calcifediol, also known as 25-hydroxycholecalciferol or 25-hydroxyvitamin D, which is produced in the liver and an indicator of a person's vitamin D level.

Researchers reached that conclusion after analyzing the serum 25(OH)D levels of the 780 cases. The normal range of the serum 25(OH)D was higher than 30 nanograms per milliliter (ng/ml), the insufficient range was between 21-29 ng/ml, and the deficient range was lower than 20 ng/ml. Out of 780 samples, 58.8% were aged younger than 50 years, 84.9% had a preexisting health condition, and 321 samples were from patients aged 50 and older. About 66.6% of 321 samples died due to COVID-19, 51.3% of them were female and 48.7% were male. But across all ages, 66.6% of those who died were male and 33.4% were female. Of those with normal vitamin D levels, 93% were still hospitalized at the time of the study. Among cases with below-normal vitamin D levels, 49.1% with insufficient vitamin D and 46.7% with deficient vitamin D died from COVID-19. Overall, those with below-normal vitamin D levels and those with preexisting health conditions were likely to die from the disease.

"To the best of the researchers' knowledge, this is the first retrospective study which determines the association of Vitamin D status and COVID-19 mortality outcome. Older and male cases with pre-existing condition and below normal Vitamin D levels were associated with increasing odds of death," the researchers wrote.

As of May 5, 2020, the World Health Organization of the United Nations reported 72,688 confirmed cases and 2,682 confirmed deaths due to COVID-19 in the Southeast Asia Region. The top three countries with confirmed cases were India at 46,433, Indonesia at 11,587, and Bangladesh at 10,143. The same three countries also had the highest deaths at 1,568, 862, and 182, respectively.



About Vitamin D Deficiency

According to Cleveland Clinic, an American academic medical center, vitamin D deficiency is a potential cause of muscle weakness, fatigue, pain, and depression. The vitamin is required for strong bones and prevention of certain types of cancer. Unlike most vitamins, vitamin D is unique due to its primary source: the skin. When ultraviolet from the sun penetrates the skin's epidermis, it photolyzes provitamin D3 that can be turned into usable vitamin D, such as calcitriol, calcidiol, and cholecalciferol. As such, the nature of vitamin D makes it a hormone, instead of a true vitamin.

Since sunlight is the trigger to produce this hormone, people with fair complexion and who are younger can convert sunshine into vitamin D better, compared to older people and those with a dark complexion. However, vitamin D can also be obtained through other means like certain foods, including egg yolks, fatty fish, and cheese. It can be obtained as well from vitamin supplements.



Throughout human history, the most prominent health conditions associated with vitamin D deficiency are rickets and osteomalacia. Rickets is a disorder in children characterized by weak and soft bones, while osteomalacia is a disorder characterized by soft bones among adults, both of which are induced by low levels of vitamin D in the body. Individuals with either disorder are prone to fractures, bone deformities, and stunted growth in children.

Vitamin D is required by the human body to use both calcium and phosphorus to build bones. Aside from that, vitamin D serves as a regulator of calcium in the blood by working with the parathyroid glands. If both calcium and vitamin D are sufficient, calcium is absorbed and used well by the body. If either of the two is insufficient, calcium is borrowed from the bones to maintain blood calcium in the normal range. But unbeknownst to many, vitamin D actually plays an integral role in regulating the immune system. The chemical helps the immune system declare and cease inflammation in the body.