Affiliation:
University of Stirling, United Kingdom
Keywords: COVID-19, Vitamin D, Obesity and VDR gene
polymorphism
COVID-19 caused thousands of deaths in the world. This global pandemic
has significantly interrupted trade, business, and education. COVID-19
disease is caused by a novel coronavirus named SARS-CoV-2. The pandemic
is caused by coronaviruses is not new during the last 20 years. Between
2002 and 2003, its sister, SARS-CoV-1, killed hundreds of people. An
important lesson from these outbreaks is that different human
populations showed disparities in susceptibility to these viruses. There
is also a different death rate between women and men. Moreover, young,
healthy people also died of COVID-19 although this disease was
previously thought for the elderly or those with pre-existing medical
conditions such as obesity or diabetes. A question as to whether or not
there is a common feature among different human populations.
Epidemiological studies currently estimate that at least one billion
people with vitamin D deficiency (1), which is common with the
elderly, but it is also associated with those, regardless of ageing,
underlying medical conditions including obesity. To date, evidence demonstrated that people with obesity may lead to the development of
vitamin D deficiency (2). An early report of the Intensive Care
National Audit and Research Centre revealed 75% of patients with severe
COVID-19 symptoms were overweight or obese (3). “It seems likely
that the increased prevalence of obesity in Italy older adults compared
to China may account for the differences in mortality between the two
countries”, William Dietz and his colleague said (4). According
to the Worth Health Organisation’ s classification, you are overweight if
your body mass index (BMI) is equal to or more than 25. BMI is “a
person’s weight in kilograms divided by the square of the person’s
height in meters (kg/m2)”. Based on WHO-BMI classification, about 39%
of adults in the world are overweight (5). People with higher BMI are also at increased risk of various diseases such as diabetes
and heart diseases. Notably, studies demonstrated that obesity is
strongly associated with an impaired immune system and severe risk of
infections, but the mechanisms involved remain unknown(6). It is hypothesised that Vitamin D receptor gene polymorphism
is responsible for the susceptibility to infections including COVID-19
among overweight or obese people.