itamin D is vital for human
health, and its deficiency may result in hypocalcemic seizures and
rickets in infants and children. The optimal cut-off of serum 25(OH)D
levels to define vitamin D deficiency are yet to be established. While,
the Endocrine Society of USA has suggested serum 25(OH)D < 20 ng/mL to
define vitamin D deficiency [1], the Institute of Medicine (IOM), USA
recommends a cut-off of 12.5 ng/mL of serum 25(OH)D [2] to define
vitamin D deficiency. Despite abundant sunshine, biochemical vitamin D
insufficiency and deficiency are reported to be quite prevalent in
apparently healthy infants, children, adolescents and pregnant women in
urban India [3-5]. Serum 25(OH)D levels <12.5 ng/mL were reported in
12-47% of under-five children and 4-28% in older children and
adolescents [5]. The biological benefits and safety of routine long-term
Vitamin D supplementation in breastfed Indian neonates are yet to be
unequivocally demonstrated. In a randomized controlled trial from Delhi
[6], directly supervised weekly vitamin D supplementation (1400 IU) in
term low birth weight newborns for six months expectedly resulted in
higher 25(OH)D levels, but there was no decrease in incidence of severe
morbidity or death. There were borderline (~0.1 SD) increases in length,
weight and arm circumference, but a paradoxical decrease in head
circumference. At age 3-6 years, the supplemented infants were
surprisingly borderline (~0.1 SD) thinner but importantly there were no
differences in any of the evaluated functional outcomes [7].
The American Academy of Pediatrics [8] and the IOM
[2] recommend routine daily supplementation with 400 IU/d vitamin D in
breastfed and partially breastfed infants, beginning in the first few
days of life and continued until the infant has been weaned and is
drinking at least 1 L/d of vitamin D-fortified infant formula or cow
milk. Many Indian newborns are now being supplemented with oral vitamin
D, despite the fact that the country is blessed with abundant sunshine,
the major source of Vitamin D synthesis. It is disappointing that in
this era of aggressive pharmacological supplementation and food
fortification, natural interventions for attaining vitamin D sufficiency
are ignored. Sunlight exposure may be advantageous as it may be safer (hypercalcemia
perspective), more cost-effective, and offer additional benefits for
mood elevation and development and maintenance of circadian rhythm,
which is required for normal growth, steroid hormone secretion and sleep
pattern.
A recent observational study on adult Indians has
documented that sunshine exposure is associated with higher serum
25(OH)D levels [9]. Outdoor manual workers in Delhi had normal vitamin D
status with mean serum 25(OH)D values between 20 and 30 ng/mL [9]. It is
possible that the lack of adequate sunshine exposure among mothers and
their offspring is resulting in a high prevalence of biochemical vitamin
D deficiency. The study by Meena, et al. [10] published in this
issue of Indian Pediatrics reminds us of the traditional Indian
practice of oil massage and sun-exposure of infants, and enthuses
evaluation of sunlight exposure to attain vitamin D sufficiency. The
authors advised mothers to expose their newborns to sunshine for a
duration of six months, when the association between duration and timing
of the sunshine exposure and serum 25(OH)D was analyzed. Interestingly,
with as little as 17 minutes/wk of sunshine exposure, one-third of the
infants achieved serum 25(OH)D above 12 ng/mL (non-deficient).
Regression models predicted that a mere 30 min/week sunshine exposure
between 10.00 am and 2.00 pm to prone infants clothed in diapers would
result in normal vitamin D level at six months of age. However, in
another before-after evaluation in 10- to 15-year-old healthy school
children, no increase in serum 25(OH)D level was documented [11]. These
findings may be reflective of suboptimal sunlight exposure in winter
months (30 minutes/d on 10% body surface area for 4 weeks). Before-after
study designs are subject to biases, and hence robust evidence to draft
clinical guidelines or policy are only possible from experimental
designs. In a randomized controlled trial (RCT) in Netherlands enrolling
232 non-Western immigrants aged 18-65 years, effect of vitamin D
supplementation (800 IU/d or 100,000 IU every 3 months) was compared
with advised sunlight exposure [12]. Serum 25(OH)D increased while serum
parathyroid hormone decreased significantly in all groups after 3 months
– more in the supplementation groups than in the advised sunlight group
(P<0.001 for the former and P<0.05 for the latter). The
results of this study are likely to be biased towards vitamin D
supplementation because sunlight exposure was advised instead of
observed, and the study included elderly participants (vitamin D
synthesis from sunlight diminishes in elderly).
In order to meaningfully inform policy, there is an
urgent need to conduct an experimental trial comparing the relative
efficacy and safety of sunlight exposure and vitamin D supplementation
in young infants. Meanwhile it would be pragmatic to promote the
customary Indian practice of sunshine exposure in young infants,
particularly among the poor who are unable to afford supplementation
costs.
1 Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon
CM, Hanley DA, Heaney RP, et al; Endocrine Society.
Evaluation, treatment, and prevention of vitamin D deficiency: an
Endocrine Society clinical practice guideline. J Clin Endocrinol Metab.
2011;96:1911-30.
2 Institute of Medicine. Dietary Reference Intakes
for Calcium and Vitamin D. Washington, DC: The National Academies Press;
2011.
3. Goswami R, Gupta N, Goswami D, Marwaha RK, Tandon
N, Kochupillai N. Prevalence and significance of low 25-hydroxyvitamin D
concentrations in healthy subjects in Delhi. Am J Clin Nutr.
2000;72:472-5.
4. Kumar GT, Sachdev HS, Chellani H, Rehman AM, Singh
V, Arora H, et al. Effect of weekly vitamin D supplements on
mortality, morbidity, and growth of low birthweight term infants in
India up to age 6 months: randomised controlled trial. BMJ.
2011;342:d2975.
5. Goswami D, Rani R, Saxena A, Arora MS, Batra S,
Sreenivas V. Maternal and neonatal vitamin-D status in twin versus
singleton pregnancies. J Obstet Gynaecol Res. 2016;42:1250-7.
6. Trilok Kumar G, Chugh R, Eggersdorfer M. Poor
Vitamin D status in healthy populations in India. A review of current
evidence. Int J Vitam Nutr Res. 2015;85:185-201.
7 Trilok-Kumar G, Kaur M, Rehman AM, Arora H, Rajput
MM, Chugh R, et al. Effects of vitamin D supplementation in
infancy on growth, bone parameters, body composition and gross motor
development at age 3-6 years: follow-up of a randomized controlled
trial. Int J Epidemiol. 2015;44:894-905.
8 Golden NH, Abrams SA; Committee on Nutrition.
Optimizing bone health in children and adolescents. Pediatrics.
2014;134:e1229-43.
9. Goswami R, Saha S, Sreenivas V, Singh N, Lakshmy
R. Vitamin D-binding protein, D status and serum bioavailable 25(OH)D of
young Asian Indian males working in outdoor and indoor environments. J
Bone Miner Metab. 2016 Jan 30. [Epub ahead of print]
10. Meena P, Dabas A, Shah D, Malhotra RK, Madhu SV,
Gupta P. Sunlight exposure and Vitamin D status in breastfed infants.
Indian Pediatr. 2017;54:105-11.
11. Marwaha RK, Yenamandra VK, Sreenivas V, Sahay R,
Baruah MP, Desai A, et al. Regional and seasonal variations in
ultraviolet B irradiation and vitamin D synthesis in India. Osteoporos
Int. 2016;27:1611-7.
12. Wicherts IS, Boeke AJ, van der Meer IM, van
Schoor NM, Knol DL, Lips P. Sunlight exposure or vitamin D
supplementation for vitamin D-deficient non-western immigrants: a
randomized clinical trial. Osteoporos Int. 2011;22:873-82.