High altitude and nail growth

Introduction

Linear nail growth in health and disease has been studied by a number of investigators. Various physiological and pathological factors affecting the nail growth have been recently reviewed by Baran and Dawber.[1] The effect of high altitude in. hypoxic conditions on nail growth has not been studied earlier to the best of our knowledge. Hence we undertook a study of nail growth at an altitude of 3445m at Leh (Ladakh).

Materials and Methods

A total of 22 healthy highlander Ladakhis and 6 lowlander troops stationed at Leh (3445m) were included in this study. All were males. Average age of highlander Ladakhis was 21.82 years (range 16 - 36 years) and of lowlanders was 34 years (range 29 - 40 years). A T- shaped cut was made on the nail plate of right index finger in each subject with a blade, 3 - 4 mm away from the proximal nail fold (PNF). Initial reading and the subsequent reading after 2 to 3 months were taken by using a Vernier Caliper with PNF as reference point.[2] In four of the lowlanders the rate of nail growth was recorded soon after fresh induction into high altitude. In two of the lowlanders the rate of nail growth was calculated for their stay in plains by taking the readings before they left the high altitude on leave and soon after their return to Leh.

Results

The rate of nail growth per day in highlanders was found to be 99.3u/day (SD 13.9u). The similar nail growth in fresh inductee lowlanders was found to be 88.7u/day (SD 10.7u/ day). Although the nail growth was found to be slower in the lowlanders inducted into high altitude, the difference was not found significant (P>0.05). Furthermore in the age matched highlanders i.e. during fourth decade with average age 34.25, years as compared to average age of 34.75 years in the lowlanders, the difference was still less significant i.e. 93.Iu/ day to 88.7u/ day.

The rate of nail growth in lowlanders during their stay in plains was found to be 11 9u/day (SD 1.4 lu), which was significantly higher than the rate of growth in lowlander inductees in high altitude (88.7u/day, SD 10.7u, P< 0.05) and also significantly higher than age matched highlander Ladakhis (93.1 u/day, SD 7.2u, P< 0.05).

Discussion

Partial pressure of oxygen at Leh (Ladakh) is only 103mm of Hg i.e. 65% of the sealevel.[3] Thus the prevailing hypoxic conditions are likely to impair the rapidly dividing cells and decrease tissue growth as has been proved by our study on nail growth. There was a significant decrease in the nail growth in high altitude as compared to the rate of nail growth seen in plains. It was further seen that rate of nail growth in highlander Ladakhis was more than lowlanders inducted into high altitude, though statistically not found significant, it does suggest degree of acclimatization in highlanders. Cold climate has been reported to decrease nail growth.[1],[5] In high altitude area both the factors of hypoxia and extreme cold climate exist. How much they contribute to decrease in nail growth in high altitude cannot be commented in the absence of studies of nail growth in purely hypoxic conditions.