Comment on: Serum Vitamin D3 Levels and Diffuse Hair Fall among the Student Population in South India: A Case-control Study.

Sir,

We read the article “Serum vitamin D3 levels and diffuse hair fall among the student population in South India: A case–control study” by Nayak et al.[1] with great interest. We commend the authors for their efforts. An observation made in the study, which is quite interesting, is the perception of the participants towards the cause for hair fall. A statistically significant difference was found in participants perceiving dietary factors as a cause for hair fall in the study. The query raised is whether details regarding diet were collected from the participants. There are some good dietary sources of Vitamin D such as milk, liver oil, egg yolk and fatty fish.[2] If these sources of food were found to be consumed or not, will make an important bearing on serum Vitamin D levels.

The highest conversion of 7-dehydrocholesterol to pre-Vitamin D3 (28.9%) in sunlight was found to occur between 11 am and 2 pm during mid-April in a study in Tirupati, a city in South India.[3] Duration of exposure to sunlight (less or more than 30 min) was recorded in the study by Nayak et al.,[1] however, the part of the day when exposure occurred was not. The differences between the two groups were found to be statistically insiginificant (p =1.00) probably due to the period of the day during which the cases and controls were exposed to sunlight was not uniform.

As evidenced by the study, only one patient had normal level of serum Vitamin D3 in spite of choosing 22 healthy controls. This study reaffirms the problem of global hypovitaminosis D.[4]

Nonetheless, the study has included many contributing factors which may affect serum Vitamin D levels. As said by the authors, Vitamin D supplementation may emerge as a routine prescription for patients with diffuse hair fall in the near future.

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Conflicts of interest

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