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Indian Pediatr 2013;50: 951-953 |
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Vitamin A Status of Low and Normal Birth
Weight Infants at Birth and in Early Infancy
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Ramesh Agarwal, #Deenanath
Virmani, *Munnalal Jaipal, Shuchita Gupta, $GS
Toteja, and Investigators of LBW Micronutrient Study Group (list
provided at the end)
From All India Institute of Medical Sciences,
Delhi,*Swami Dayanand Hospital, #Kasturba Hospital and $Indian Council
of Medical Research, New Delhi, India.
Correspondence to:
Dr Ramesh Agarwal, Associate Professor, Department of
Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New
Delhi 110 029, India.
Received: December 18, 2012;
Initial review: December 20, 2012;
Accepted: March
12, 2013.
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Serum retinol levels of low birth weight (LBW; birth weight <2500g) and
normal birth weight (NBW; birth weight
³2500g)
infants were evaluated at birth and 3 months using high performance
liquid chromatography. At birth, levels were 13.3±8.2 µg/dL in LBW (n=146)
and 14.0±6.2 µg/dL in NBW infants (n=79; p=0.51), with 41.1% of
LBW and 24.1% of NBW infants having vitamin A deficiency (VAD, <10 µg/dL;
P=0.01). At follow up, levels were 18.0±9.4 µg/dL in LBW (n=83)
and 20.0±7.3 µg/dL in NBW infants (n=51; P=0.19), with
18.1% of LBW and 3.9% of NBW infants having VAD (P=0.02).
Keywords: Infant, Low Birth Weight, Retinal,
Vitamin A.
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Vitamin A is an important micronutrient required
for maintaining adequate growth and development, epithelial cell
integrity and visual, reproductive and immune functions. The prevalence
of subclinical vitamin A deficiency (VAD) in India is quite high,
ranging from 31% to 57% among preschool children [1]. Limited data is
available on vitamin A status of specific high risk groups like low
birth weight (LBW; birthweight <2500 g) infants. We herein report the
vitamin A status of LBW infants from Delhi, compared to the normal birth
weight (NBW; birthweight ³2500
g) infants, at birth and at 3 months of age.
Methods
The present results are part of a larger study which
evaluated micronutrient status of LBW and NBW infants at birth and in
early infancy [2,3]. This was a prospective observational study
conducted in 2009-2010 at three hospitals of Delhi. Ethics Committee of
all collaborating hospitals approved the protocol.
All live born, clinically stable infants were
enrolled consecutively in LBW and NBW categories following informed
consent from parents. Venous blood samples of the enrolled mothers and
infants were drawn within first 48 hours of birth. Mothers received
routine iron and calcium supplementation and no additional
multivitamin/micronutrient supplementation as part of the study. Infants
were also not provided any multivitamin/micronutrient supplementation as
part of the study. Follow up samples were taken at 14±4 weeks of
corrected age. Detailed methodology has been given in a previous
publication [3].
Primary outcome was serum retinol as measured by high
performance liquid chromatography; (Shimadzu LC-6AD Binary Gradient
System). VAD was defined as serum retinol level of less than 10 µg/dL
[4,5,6]. Data were analyzed
using Stata 11.0 (College Station, Texas, USA). Continuous normally
distributed data were analyzed using Student’s t-test, and categorical
data using chi square test. The change in retinol values from birth to
follow up was analyzed using multiple linear regression and proportions
deficient were compared using multiple logistic regression.
Results
A total of 220 LBW and 119 NBW infants were enrolled.
Of these, serum retinol levels were available for 146 LBW and 79 NBW
infants and their mothers at birth and of 83 LBW and 51 NBW infants at
follow up. The baseline characteristics of study infants at birth and
follow up are outlined in Table I. Serum retinol levels of
mothers and infants are shown in Table II, along with
proportion of subjects deficient in serum retinol.
TABLE I Demographic and Infant Variables at Birth and Follow up*
Variables |
Low Birth Weight infants
|
Normal Birth Weight infants |
P |
|
(n=146) |
(n=79) |
|
Demographic variables |
Maternal education (completed years)
|
10 (0 -15) |
8 (0 -15) |
0.58 |
Family income (thousand Rs./month) |
3.8 (2-10) |
4 (2-20) |
0.11 |
Infant variables at birth
|
Male gender |
70 (47.9%) |
38 (48.1%) |
<0.01 |
Birth weight (g) |
1920±328 |
2988±312 |
<0.01 |
Gestation (wk) |
36.0±2.4 |
38.7±1.1 |
< 0.01 |
Infant variables at follow-up visit# |
No. of infants with retinol results available
|
83 (56.8%) |
51 (64.5%) |
0.26 |
Postnatal age (wk) |
12.0 (8.0-37.0) |
13.0 (6.0-34.0) |
0.87 |
Micronutrient/multivitamin supplementation received |
23/83 (27.7%) |
8/51 (15.7%) |
0.04 |
Exclusive/predominant breastfeeding |
72/83 (86.7%) |
47/51 (92.2%) |
0.55 |
Data expressed as number (percentage), or median (interquartile
range). |
TABLE II Serum Retinol Levels of Mother-infant Dyad at Birth and of Infants at Follow up Visit
Variables |
Low Birth Weight infants |
Normal Birth Weight infants |
P |
|
n |
Results
|
n |
Results
|
|
Infant levels at birth |
Serum Retinol (µg/dL)
|
146 |
13.3±8.2 |
79 |
14.0±6.2 |
0.51 |
Serum Retinol <10 µg/dL |
|
60/146 (41.1%) |
|
19/79 (24.1%) |
0.01 |
Infant levels at follow up visit
|
Serum Retinol (µg/dL)
|
83 |
18.0±9.4
|
51 |
20.0±7.3 |
0.19 |
Serum Retinol <10 µg/dL |
|
15/83 (18.1%) |
|
2/51 (3.9%) |
0.02 |
Maternal levels at birth
|
Serum Retinol (µg/dL)
|
122 |
39.0±15.5 |
78 |
38.1±16.3 |
0.69 |
Serum Retinol <20 µg/dL |
|
14/122 ((11.5%) |
|
7/78 (9.0%) |
0.57 |
Data expressed as number (percentage) or mean±SD. |
The change in the serum retinol levels from birth to
follow up visit was comparable in both groups with increasing age. The
proportion of deficient infants did not increase significantly with
increasing age, but the LBW infants had significantly higher chance of
being deficient (OR=5.3; 95% CI 1.2, 24.2) compared to the NBW infants
at follow up (P=0.03).
The mean maternal levels of LBW and NBW infants were
39.0 µg/dL (n=122) and 38.1 µg/dL (n=78), respectively (P=0.69);
with 11.5% of LBW and 9.0% of NBW infants’ mothers having VAD (serum
retinol <20 µg/dL; P=0.57). There was no correlation between
maternal and infant serum retinol levels at birth (r=0.26).
Discussion
The mean serum retinol levels of LBW infants in our
study were low, though comparable to NBW infants at birth as well as at
follow up in early infancy. All infants are born with low vitamin A
stores, including those born to well-nourished mothers with abundant
vitamin A stores [7]. The reported proportion of infants with serum
retinol below 20 µg/dL at birth is very variable, ranging from 0-89% in
developing countries, as against 0-29% in industrialized countries [7].
This has been proposed to be due to higher rates of preterm deliveries
and LBW in developing countries [7], as both these factors have been
shown to be associated with low neonatal serum retinol levels [8].
Breast milk is the primary source of vitamin A in
first months of life, and it has been shown that even infants fed by
vitamin A-deficient mothers whose breast milk provides as little as 120
± 15µg RE/day grow normally and have no clinical signs of VAD [9]. Most
of our infants whose follow up results are available were
exclusively/predominantly breastfed, and most mothers had adequate
levels of vitamin A. The proportion of deficient infants therefore
decreased with increasing age in our study. However, the proportion of
LBW infants with VAD was significantly higher compared to NBW infants at
birth as well as at follow up in early infancy. It therefore suggests
that exclusive breastfeeding might not be sufficient to maintain serum
retinol levels of LBW infants during early infancy. Current
recommendations do not support daily oral vitamin A supplementation to
human milk fed LBW infants due to lack of evidence of benefit [10].
However, looking at the deficiency status among these infants, it might
be worth examining the role of such supplementation to these infants.
Another relevant point to note is that zinc and
vitamin A concentrations tend to co-vary in marginally nourished
individuals with co-existing zinc and vitamin A deficiencies, and zinc
deficiency might limit the health and nutritional effect of vitamin A
interventions in a population [11]. It is therefore important to note
that our study population also had significant zinc deficiency (present
in 51.0% and 79.0% of LBW and 42.4% and 66.7% of NBW infants at birth at
follow-up, respectively) [3].
We targeted a study population representative of
neonatal population in developing countries at highest risk of
nutritional deficiencies. We followed these infants till three months of
age and reported how the levels evolved during early infancy, with
simultaneous comparison with normal birth weight infants, thereby
providing a comparative picture. Our study had limitations in terms of
being based on a sample size of convenience and a significant loss to
follow-up. However, the baseline characteristics of infants who were
followed up versus those who were lost to follow up were
comparable.
Contributors: RA, DV, MLJ,GST designed research
(project conception, development of overall research plan, and study
oversight) and shall be the overall guarantor; RA, DV, MLJ,GST conducted
research; GST additionally carried out the laboratory analysis; SG, RA:
analyzed data, performed statistical analysis; SG, RA: wrote paper.
Funding: Indian Council of Medical
Research, Delhi; Competing interests: None stated.
Investigators of LBW Micronutrient Study Group:
AIIMS: Agarwal R (PI), Paul VK, Deorari AK,
Sreenivas V, Gupta S, Sankar MJ, Yadav CP, Suresh S, Saxena M, Thukral
A, Mittal D, Rakesh G, Thomas S, Kuriakose R, Thareja A, Tanupriya,
Sarasan S, Honeymol KC, Lal S.
Swami Dayanand Hospital: Jaipal ML (PI), Devgan V
(PI), Agarwal A (PL), Venugopal M, Saini A, Bisht SS, Tyagi A, Grover R,
Kumari G.
Kasturba Hospital: Virmani DN (PI), Bhatia S
(PI), Jaipal ML (PI), Kudesia M, Duggal AK, Govil A, Verma KK, Mehta S.
ICMR: Toteja GS, Rao S, Gupta P.
(PI: Principal Investigator)
What This Study Adds?
• Information on vitamin A status of low birthweight infants
at birth and in early infancy.
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