A growing number of Koreans are seeking medical attention for vitamin D deficiency, a common condition among those who do not get enough exposure to sunlight, a government report showed.
According to the National Health Insurance Service, the number of Koreans who sought medical help for vitamin D deficiency increased ninefold from 2009-2013 ― from 2,027 to 18,637.
"More people are now aware that vitamin D deficiency can affect one's muscles, bones and immunity and is even associated with cancer," said Lee Sang-hyun, a doctor at the National Health Insurance Service Ilsan Hospital.
"On top of the increased number of people who spend a lot of time indoors, many also choose to be proactive about the condition since they know what risks it carries.
These are some of the reasons why the number of patients increased so dramatically."
Vitamin D deficiency is known to cause a number of health problems including light-headedness, muscle aches and weakness.
It is also associated with rickets, a nutritional disorder that leads to softened bones and skeletal deformities, as well as osteoporosis, a bone disease that can lead to an increased risk of fracture.
According to the state-run agency, more Korean women were treated for vitamin D deficiency than Korean men.
In 2013, 13,677 Korean women consulted a medical professional for the condition, 2.75 times more than the 4,960 Korean men.
"Vitamin D is produced by the body in response to skin being exposed to sunlight," Lee said.
"A lot of women wear sunscreen before they go out, and this often makes it more difficult for their body to produce vitamin D ― as it can block vitamin D-producing UV rays."
Sunscreens with a sun protection factor of 8 or more appear to block vitamin D-producing UV rays, he added.
Those in their 50s and 60s were the largest group of patients.
Children aged 9 and under were the second-largest group that sought medical treatment for vitamin D deficiency.
"Aging decreases the human skin's capacity to produce vitamin D," Lee explained.
"As for young children, I think it has to do with them not spending enough time outdoors."
Aside from sun exposure, vitamin D occurs naturally in a number of foods, including egg yolks, mushrooms and fish such as salmon and mackerel.
However, Lee said the best way to get more vitamin D is to get enough exposure to sunlight, about 15 to 20 minutes every day.
"If you are wearing sunscreen on your face, make sure either your arms or legs are exposed to the sun," he said.
If it is not possible to spend much time in the sun or one is always careful about covering one's skin, taking a vitamin D supplement is recommended.
To optimize bone health and prevent osteoporosis, Lee recommended taking 800 international units of vitamin D every day.