5 Hydroxy Cholecalciferol Levels in Infants with Hypocalcemic Seizures

Abstract

Objective: To determine the prevalence of vitamin D deficiency (25-hydroxycholecalciferol) in infants with hypocalcemic seizures and the relation of severity of vitamin D (25-hydroxy Cholecalciferol) deficiency with the occurrence of hypocalcemic seizures. Design: Cross sectional analytical study. Setting: pediatric emergency department of a tertiary care hospital. Methods: 60 consecutive term neonates and infants (upto 1 year) presenting with seizures with documented hypocalcemia (total serum calcium was <8 mg/dl, with normal serum albumin levels (≥4 mg/dl) were included as cases and 60 healthy term neonates and infants attending immunization clinic were taken as controls. A structured questionnaire was asked and blood samples taken for serum calcium, phosphorus, alkaline phosphatase, 25 hydroxycholecalciferol, albumin levels. Radiological assessment of rickets was also done in clinically suspected cases. Results: Majority of the cases had inadequate exposure to sunlight (73.3%) as compared to controls (41.7%). Vitamin D deficiency is seen in 88.3% cases and 68.3% controls (p=0.01). 31.7% of the cases were severely deficient in vitamin D. Thus vitamin D deficiency appears to be a major risk factor for hypocalcemic seizures. No significant relation between 25(OH)D and calcium in both cases and controls using spearman rank correlation. There was a significant inverse relation between 25(OH)D and S.ALP among controls and cases. Conclusion: High prevalence of vit D deficiency was noted in infants with hypocalcemic seizures however a high prevalence of vitamin D deficiency was also seen in healthy infants. Serum alkaline phosphatase can be taken as surrogate marker for vit D deficiency. Sunlight exposure < 30 minutes/week was likely to develop vitamin D Deficiency.

Full text

5 Hydroxy Cholecalciferol Levels in Infants with Hypocalcemic Seizures
Richa Malik1*, Mohapatra JN2, Kabi BC3 and Rohan Halder4
1Resident, Department of Pediatrics, Vardhaman Mahavir Medical College & Safdarjang Hospital, New Delhi, India
2Associate Professor, Department of Pediatrics, Vardhaman Mahavir Medical College & Safdarjang Hospital, New Delhi, India
3Professor, Department of Biochemistry, Vardhaman Mahavir Medical College & Safdarjang Hospital, New Delhi, India
4Resident, Department of Pediatrics, Vardhaman Mahavir Medical College & Safdarjang Hospital, New Delhi, India
*Corresponding author: Richa Malik, Resident, Department of Pediatrics, Vardhaman Mahavir Medical College & Safdarjang Hospital, New Delhi, India, Tel:
9871356832; E-mail: malik.richa86@gmail.com
Rec Date: Feb 27, 2014, Acc Date: Apr 10, 2014, Pub Date: Apr 14, 2014
Copyright: © 2014 Malik R, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract
Objective: To determine the prevalence of vitamin D deficiency (25-hydroxycholecalciferol) in infants with
hypocalcemic seizures and the relation of severity of vitamin D (25-hydroxy Cholecalciferol) deficiency with the
occurrence of hypocalcemic seizures.
Design: Cross sectional analytical study.
Setting: pediatric emergency department of a tertiary care hospital.
Methods: 60 consecutive term neonates and infants (upto 1 year) presenting with seizures with documented
hypocalcemia (total serum calcium was <8 mg/dl, with normal serum albumin levels (≥4 mg/dl) were included as
cases and 60 healthy term neonates and infants attending immunization clinic were taken as controls. A structured
questionnaire was asked and blood samples taken for serum calcium, phosphorus, alkaline phosphatase, 25
hydroxycholecalciferol, albumin levels. Radiological assessment of rickets was also done in clinically suspected
cases.
Results: Majority of the cases had inadequate exposure to sunlight (73.3%) as compared to controls (41.7%).
Vitamin D deficiency is seen in 88.3% cases and 68.3% controls (p=0.01). 31.7% of the cases were severely
deficient in vitamin D. Thus vitamin D deficiency appears to be a major risk factor for hypocalcemic seizures. No
significant relation between 25(OH)D and calcium in both cases and controls using spearman rank correlation.
There was a significant inverse relation between 25(OH)D and S.ALP among controls and cases.
Conclusion: High prevalence of vit D deficiency was noted in infants with hypocalcemic seizures however a high
prevalence of vitamin D deficiency was also seen in healthy infants. Serum alkaline phosphatase can be taken as
surrogate marker for vit D deficiency. Sunlight exposure < 30 minutes/week was likely to develop vitamin D
Deficiency.
Keywords: Hypocalcemia; Seizures; 25-hydroxycholecalciferol
Introduction
Seizures are common in pediatric age group occurring in 4-7% of
infants and children [1]. Amongst the various etiologies
hypocalcaemia is a major biochemical cause of seizures in infancy in
the developing countries [2,3]. It constitutes 25.6% of afebrile seizures
in children [4]. Causes of hypocalcemic seizures include prematurity,
birth asphyxia, exogenous phosphate load, magnesium deficiency,
hypoparathyroidism, malabsorption syndromes, pancreatitis,
hypoalbuminemia (pseudohypocalcemia) and vitamin D deficiency
[5]. Hypocalcemia due to vitamin D deficiency constitutes an
important cause of infantile seizures in developing countries. Infants
are a vulnerable population for developing deficiency due to their high
rate of skeletal growth. A state of deficiency occurs months before
rickets is obvious on physical examination and most frequently it
presents as seizures.
The role of vitamin D has been found in central nervous system
where its functions are mediated through vitamin D receptors [6].
Through its receptor, vitamin D down-regulates interleukin-6 (IL-6)
which is a proconvulsant and up-regulates GDNF and NT-3
(anticonvulsant neurotrophic factors). Vitamin D stimulates
expression of calcium-binding proteins known to exert antiepileptic
effects [7]. Serum 25 (OH) vitamin D level is the best available
biomarker for the diagnosis of vitamin D deficiency. A level below 20
ng/ml or 50 nmol/l (cut off) is now considered insufficient by Lawson
Wilkins Pediatric Endocrine Society in the USA [8].
There is paucity of Indian data studying association of
hypocalcemic seizures in infants with hypovitaminosis D. This study
was designed to find out the prevalence of vitamin D deficiency in
infants with hypocalcemic seizures so that vitamin D supplementation
can be considered as an adjuvant therapy for the prevention and
control of hypocalcemic seizures.
Malik et al., J Nutr Food Sci 2014, 4:3
DOI: 10.4172/2155-9600.1000271
Research Open Access
J Nutr Food Sci
ISSN:2155-9600 JNFS, an open access journal Volume 4 • Issue 3 • 1000271
Journal of Nutrition & Food Sciences
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Methods
Ours was a crossectional analytical study conducted at a tertiary
care hospital (Safdarjung hospital, New Delhi) in the department of
Pediatrics. Subjects were recruited between January 2011 to december
2011.
All the term neonates and infants (upto 1year) presenting with
seizures and having documented hypocalcemia (total serum calcium
was <8 mg/dl, with normal serum albumin levels (≥4 mg/dl) were
included as cases in the study. Using the prevalence of hypocalcemic
seizure 11% [9], alpha error 5%, power 90%, sample size was taken to
be 60. Same number of healthy term neonates and infants attending
immunisation clinic were taken as controls. Infants with history of
intake of calcium or vitamin D supplementation, infants with other
causes of seizures-meningitis, hypoglycemia, structural brain
malformation, history of birth asphyxia, congenitally malformed
infant or infant of diabetic mother were excluded from study. A
written informed consent was obtained from the parents for enrolling
their child for the study. The study protocol was approved by the
Ethics Committee of the Hospital.
A structured questionnaire was used to obtain information for all
cases and controls. A detailed history and clinical examination was
done for each child. Breastfeeding was categorised as exclusive
breastfeeding for 1st 6 months of life or not exclusively breastfed. Not
exclusively breast fed were categorised further as those on mixed
feeding (breastfed +animal/toned milk) and those on total animal/
toned feeding before 6 months of age. Season during which an infant
presented with seizure was also recorded. Between November to
February was taken as winter and between March to October was
taken as summer. Information regarding sun exposure was collected.
Minimum recommended exposure is defined as when the infant is
exposed to sunlight for at least 30 minutes in a week with arms, legs
and trunk exposed. 2 hrs is the minimum required period weekly if
only face is exposed to sunlight. On examination, anthropometric data
was compared. Sign of vitamin D deficiency were recorded by
examining clinician as presence of wrist widening. Infants with wrist
widening were subjected to radiography of left wrist to detect features
of rickets.
Blood sample collection was done under strict aseptic conditions
without using tourniquet; 3 ml blood was drawn by venepunture. 1.5
ml blood was immediately sent for measuring serum calcium & serum
phosphorus level using autoanalyser, serum alkaline phosphatase level
by spectrophotometer and serum albumin level. Remaining 1.5 ml was
immediately taken for serum separation by centrifugation. Separated
serum was stored at +2 to +8°C in refrigerator to estimate 25(OH)D
using ELISA method. Routine investigations to rule out other causes of
seizure in infancy were also performed.
Vitamin D (25-hydroxy cholecalciferol) deficiency was defined as
25-hydroxy vitamin D levels < 50 nmol/L or 20 ng/ml (cut off level).
Severe deficiency was level are <12.5 nmol/l or <5 ng/ml [8].
Statistical analysis
Data was analyzed using SPSS software version 16.0. Statistical
significance of quantitative variables between the study and control
group was determined by unpaired student t-test or non-parametric
Mann Whitney test. Statistical significance of qualitative variables was
determined by chi square test or Fischer exact test. Spearman rank
correlation was calculated to find the strength of relationship between
various quantitative variables. P ≤ 0.05 was taken as level of statistical
significance.
Results
A total of 480 infants presented with seizures in pediatric
emergency during the study period (January 2011 to December 2011),
out of which 60 were taken as cases fulfilling inclusion criteria. 60
healthy term neonates or infants were taken as controls. None of them
received calcium or vitamin D supplementation.
Baseline data comparison of cases and controls is shown in Table 1.
It shows the mean age, mean weight and mean length of cases were
6.11, 5.89 and 62.72 respectively. The mean age, mean weight and
mean length of controls were 5.9, 6.18 and 62.70 respectively.
Statistically there was no significant difference in mean age, weight
and length between the two groups (p value- not significant). Among
cases, 33/60 children and among controls, 35/60 were of age between
6-12 months and rest were below 6 months. There was no significant
difference between two groups in relation to age (p=0.713). In both
groups, males were predominant (55% and 60% of cases and controls
respectively). The feeding pattern among cases and controls of
0-6month age group showed that most of the infants in cases and
controls were exclusively breast fed (29/35 and 24/28 in cases and
controls respectively). There was a seasonal variation in the
presentation of seizures as more cases presented in winter (55% or
33/60) but it was not statistically significant. We also compared
adequacy of sunlight exposure in cases and controls. Majority of the
cases i.e. infants with hypocalcemic seizures had inadequate exposure
to sunlight (44/60 or 73.3%) as compared to controls (31/60 or 41.7%)
which was statistically significant (p<0.05).
Parameter Cases
Mean ± SD
Controls
Mean ± SD
P Value
Sample Size 60 60 -
Age(months) 6.11 ± 3.80 5.9 ± 3.43 0.753
Sex- male
Female
33
27
36
24
0.580
Weight(kg) 5.897 ± 2.18 6.18 ± 2.03 0.455
Length(cm) 62.72 ± 6.63 62.70 ± 6.34 0.990
Weight/age 1 1 -
Length/age 1 1 -
Table 1: Comparison of baseline parameters
Table 2 shows comparison of various biochemical parameters in
cases and controls. Mean level of 25(OH)vitamin D in cases and
controls was 28.79 and 47.62 respectively, which was significantly low
in cases as compared to controls (p<0.05). Also, there was significant
difference in the mean Serum Alkaline Phosphatase (S.ALP) levels
between cases and controls (p<0.05). However there was no significant
difference in serum phosphorus levels between two groups (p=0.361).
On comparing vitamin D status in cases and controls, vitamin D
deficiency (<50 nmol/l) was seen in 88.3% (53/60) cases and 68.3%
(41/60) controls. This difference was statistically significant (p<0.05).
In both groups, serum alkaline phosphatase levels was found to be
Citation: Malik R, Mohapatra JN, Kabi BC, Halder R (2014) 5 Hydroxy Cholecalciferol Levels in Infants with Hypocalcemic Seizures. J Nutr Food
Sci 4: 271. doi:10.4172/2155-9600.1000271
Page 2 of 4
J Nutr Food Sci
ISSN:2155-9600 JNFS, an open access journal Volume 4 • Issue 3 • 1000271

elevated in most of the children, 44/60(73.3%) cases and 39/60(65%)
controls.
We also studied severity of vitamin D deficiency in cases and
controls. 31.7% (19/60) of the cases were severely deficient in vitamin
D whereas amongst controls, out of total vitamin D deficient children,
only 16.7% cases were severely deficient (p<0.05). Among cases, both
mild and severe deficiency was seen in 31.7% cases (19/60 in each), so
the severity of vitamin D deficiency did not have any relation to the
occurrence of seizures.
Cases
Mean ± SD
Controls
Mean ± SD
P Value
Sample size 60 60 -
S. Calcium (mg/dl) 6.98 ± 0.96 8.86 ± 1.15 <0.05
S.Phosphorus (mg/dl) 5.06 ± 1.74 4.73 ± 1.39 0.361
S.Alp (IU/L) 660.13 ± 352.05 440.72 ± 222.62 <0.05
S.Vitamin D(nmol/l) 28.79 ± 33.85 47.62 ± 46.16 <0.05
Table 2: Comparison of biochemical parameter
Among all hypocalcemic infants with seizures, 41.7% (25/60)
showed wrist widening and out of these, 25% (15/60) had evidence of
rickets on X ray wrist.
Relation was studied between 25hydroxy vitamin D, serum calcium
and serum ALP levels using spearman rank correlation (Tables 3 and
4). No significant relation was seen between 25 hydroxy vitamin D and
serum calcium in both cases (r=0.198, p=0.13) and controls (r=0.445,
p=0.06). However, a significant inverse relation between 25(OH)D and
S.ALP among controls (r = -0.615, p<0.05) and cases (r =-0.213,
p<0.05) was noticed.
S. vitamin D S. calcium S. ALP
S. vitamin D r=1 r=0.445, p=.000 r= -0.615, p<0.05
S. calcium r=0.445, p=.000 r=1 r=-0.252, p=0.052
Table 3: Relation of various parameters among cases
# Correlation coefficient
S. vitamin D S. calcium S. ALP
S.vitamin D r=1 r=0.445, p=.000 r= -0.615, p<0.05
S.calcium r=0.445, p=.000 r=1 r=-0.252, p=0.052
Table 4: Relation of various parameters among controls
Discussion
There has been increasing global interest regarding the role vitamin
D in health and disease. Vitamin D deficiency continues to be a public
health problem, prevalent in many Asian countries. In our study,
vitamin D levels and other associated factors were studied in infants
with hypocalcemic seizures.
Among hypocalcemic seizure patients (cases) of 0-6months age,
82% were exclusively breast fed, 11.5% were on mixed feeding and
5.7% were on animal/toned milk. Out of total, in 41.7% cases
complementary feeding was started soon after 6 months. These results
were comparable Manzoor Ali Khan et al. study [10] and Ahmed et al.
study [2].
Our study reported a marginally higher incidence of hypocalcemic
seizure during winter season (55% of cases presented during nov-feb.).
Whereas, Ahmed et al. reported [2] that 70% cases were seen in winter
months.
Inadequate sunlight exposure was an important contributing factor
for development of vitamin D deficiency rickets which in turn is a
common cause of hypocalcemia in children. Our study highlighted
that majority of the cases (73.3%) had a history of limited sunlight
exposure than controls (51% controls reported to have inadequate sun
exposure). This difference is statistically significant (p<0.05). This was
consistent with Manzoor Ali Khan et al. [10] study which reported that
68% of children with hypocalcemic fits had poor sun exposure. It was
also comparable with other studies of Mivako et al. [11] and Erfan et
al. [12] (Figure 1).
Figure 1: Vitamin D supplement Criteria
Bio-chemical parameters included in present study were serum
calcium, serum phosphorus, serum ALP and most importantly serum
25 (OH)D. Mean serum 25 (OH)D was very low among cases (mean
28.79 ± 33.85) than controls (mean 47.62 ± 46.16) and this difference
is highly significant (P=0.008). This means that hypocalcemic seizures
were very likely to be associated with low serum vitamin D levels (<50
nmol/litre). Most of the infants with hypocalcemic fits (88.3%) were
reported to have low serum vitamin D levels. Thus vitamin D
deficiency appears to be a major risk factor for hypocalcemic seizures.
These results were comparable to Mehrorta et al. study [13] that
studied 60 hypocalcemic seizure infants along with their mothers and
demonstrated high prevalence of hypovitaminosis D in these infants
(90%) and their mothers (85%). However, vitamin D deficiency was
also found to be prevalent in our control population (68.3% had low
serum vitamin D levels). This was comparable to some studies on
Indian infants [14] which reported vitamin D deficiency in 66.7% of
healthy breast fed term infants at 3 months of age. The reason for this
high prevalence of hypovitaminosis D in India may be related to
decrease cutaneous synthesis owing to higher skin pigmentation and
lower duration, as well as less surface area exposed to sun. This is due
to greater coverage of body and lesser participation in outdoor
activities. Intake of vitamin D is also inadequate as food items in India
are not fortified and there is no policy of routine vitamin D
supplementation in pregnant or lactating women and infants. Indian
Citation: Malik R, Mohapatra JN, Kabi BC, Halder R (2014) 5 Hydroxy Cholecalciferol Levels in Infants with Hypocalcemic Seizures. J Nutr Food
Sci 4: 271. doi:10.4172/2155-9600.1000271
Page 3 of 4
J Nutr Food Sci
ISSN:2155-9600 JNFS, an open access journal Volume 4 • Issue 3 • 1000271

diet is low in calcium and high in phytates which may contribute by
causing secondary hyperparathyroidism [15].
In the present study, vitamin D deficiency was further classified
based on concentration of serum 25(OH)D. Deficiency is found to be
symptomatic in form of hypocalcemic seizures but the severity of
deficiency does not have any relation with the occurrence of seizures
in hypocalcemic infants.
Our study reported that low vitamin D levels were associated with
increased serum ALP levels (>341 IU/litre). Another novel observation
was a significant inverse relation between 25(OH)D and S.ALP in
cases (r=-0.213, p<0.05) as well as controls (r=-0.615, p<0.05) which
was comparable to Jain et al. [14]. It can be concluded that elevated
S.ALP is a marker of vitamin D deficiency if liver pathology is
excluded. However, Mehrotra et al. [13] found no significant
correlation between vitamin D, calcium or ALP in study infants with
hypocalcemic seizures.
To conclude, vitamin D deficiency is an important etiological factor
for hypocalcemic seizures in infancy. Sunlight exposure for <30
minutes/week is a leading risk factor for development of vitamin D
deficiency among infants. Elevated serum ALP can be a surrogate
marker of vitamin D deficiency provided other causes of raised S.ALP
are excluded. So, vitamin D supplementation can be considered as an
adjuvant therapy in the management of hypocalcemic seizures along
with use of intravenous and oral calcium.
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Citation: Malik R, Mohapatra JN, Kabi BC, Halder R (2014) 5 Hydroxy Cholecalciferol Levels in Infants with Hypocalcemic Seizures. J Nutr Food
Sci 4: 271. doi:10.4172/2155-9600.1000271
Page 4 of 4
J Nutr Food Sci
ISSN:2155-9600 JNFS, an open access journal Volume 4 • Issue 3 • 1000271