Chennai: The major source of vitamin D is exposure to sunlight, but of late, there have been reports saying that vitamin D deficiency is on the rise in the city where sunlight is not limited. An official from a laboratory points out that more people are coming forward to do vitamin D3 test as awareness about this is increasing.
“We have plenty of sunshine in our country and it looks paradoxical that we are deficient in vitamin D.
So, the main question is the interpretation of the present commercially available test in our country,” says Dr Rajan Ravichandran, director, MIOT institute of nephrology, adding that the present test estimates total 25 hydroxycholecalciferol, consisting of 3 parts - the form bound to the vitamin D binding protein (85 per cent), the form bound to albumin (15 per cent) and free or bio available form (0.03 per cent).
He says that only the free form is important for bone health, whereas laboratory tests show the result of the entire forms.
Dr Ravi Thadhani, chief of nephrology at Massachusetts General Hospital in Boston, has stated in the New England Journal of Medicine that doctors may be over-diagnosing vitamin D deficiency in black patients.
The definition of vitamin D deficiency needs to be rethought as doctors use a blood test that measures a person’s total 25-hydroxyvitamin D level.
“The test is being done widely and is costly. It requires careful interpretation to avoid unnecessary vitamin D supplementation and its consequences,” says Dr Ravichandran.
A recent article published in a British journal interprets that continuing widespread use of vitamin D for osteoporosis prevention in community-dwelling adults, without specific risk factors for vitamin D deficiency, seems to be inappropriate.
Dr Anita Suryanarayan, chief of laboratory services, Lister Metropolis, says that the free form test is also available but is costly compared to the total form test.
Stressing that vitamin D test is needed and helps many people who complain of muscle and diffuse pain, Dr Sivamurugan, orthÂopaedic surgeon of SounÂdarÂapandian Bone and Joint Hospital, says that patients have benefited due to vitamin D supplements.
“The test is not for everyone. But we prescribe it for a select few and the results have revealed vitamin D deficiency. Also, vitamin D supplements have helped these patients,” says the orthopaedic surgeon.
