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Indian Pediatr 2018;55: 72 -73 |
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Hypoferremic State in Overweight and Obese
Children
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D Siyaram, *P
Bhatia, D Dayal, AK Bhalla and R Marathe
Department of Pediatrics, Advanced Pediatrics Centre,
PGIMER, Chandigarh, India,
Email:
[email protected]
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Children with high body mass index (BMI) are at risk of iron deficiency.
In present study, 71 children with overweight or obesity were screened
for iron deficiency. Mean BMI, ferritin and plasma soluble transferrin
receptor (sTrfR) levels were 26.1 kg/m2, 41.9 µg/L and 0.375 mg/L,
respectively. Twenty (28%) children had anemia, and 44 (62%) had an
underlying hypoferraemic state.
Keywords: Anemia, Body Mass Index, Iron deficiency.
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O besity is a low grade chronic inflammatory state
with subclinical elevated levels of cytokines like IL-1b and TNF-á,
which can affect iron sequestration and lead to a state of functional
iron deficiency [1]. In addition children who are overweight or obese
are at high risk of development of true iron deficiency primarily due to
deficient iron intake and food fads and also due to deficient stores
because of increased iron requirement owing to their larger blood volume
[2]. The present study was undertaken to screen overweight and obese
children in our institute for true hypoferraemic state based on serum
ferritin and soluble transferrin receptor levels.
This cross-sectional study was conducted on 71
children aged 2-14 years between July 2015 to June 2016. Body mass index
(BMI) was determined by calculating body weight/height 2
(kg/m2), and BMI Z scores
(BMIZ) were estimated using WHO reference charts. Enrolled cases were
divided into overweight (BMIZ +1 to +2), obese (BMIZ +2 to + 3) and
morbid obesity (BMIZ +3 Z). Anemia in 2-14 year age group and the
ferritin cut-off to define hypoferraemic state were based on WHO
criteria [3]. Plasma soluble transferrin receptor assay (sTrfR) was
performed using sandwich ELISA method (Sincere Biotech). We had
established a normal range for pediatric sTrfR assay in our healthy
cohort as 0.17-2.1 mg/L [4]. Iron deficiency (ID) was defined as
combination of either normal hemoglobin (Hb) for age and ferritin <30
µg/dL or normal for age and sTrfR levels >2.1 mg/L, while iron
deficiency anemia (IDA) was defined as low Hb for age and ferritin <30
µg/dL or low Hb for age and sTrfR levels >2.1 mg/L. This study was
approved by the ethics committee of the institute.
The demographic and hematological parameter are
detailed in Table I. Serum ferritin was low in 44 (62%),
normal in 25 (35%), and high in only 2 (3%) children.Among these, 69
(97.2%) had normal transferrin receptor level and only one child each
had high or low levels. Anemia was noted in 20 (28%) cases; however, a
hypoferraemic state could be identified in 44 (62%) cases. Out of 20
cases with anemia, 7 (35%) had anemia of chronic disease while 13 (65%)
had iron deficiency anemia. In 44 cases with hypoferraemic state, 31
(70%) had evidence of iron deficiency alone and 13 (30%) had iron
deficiency anemia. Anemia and hypoferraemic state was noted to be
present in all three groups without any statistical difference (Table
I). The mean sTrfR level among three groups had a rising trend but
the difference was not statistically significant.
TABLE I Demographic and Hematological Profile in Children with High Body Mass Index
Parameters |
Overweight (n=6) |
Obese (n=35) |
Morbid Obesity (n=30) |
P value |
Total |
Age (y) |
10.5 (1.5) |
10.2 (2.5) |
7.9 (2.6) |
0.00 |
9.3 (2.7) |
Male/Female |
3/3 |
26/9 |
19/11 |
0.409 |
48/23 |
BMI (kg/m2) |
21.1 (2.3) |
24.8 (2.5) |
28.74 (5.2) |
0.00 |
26.1 (4.5) |
Hb (g/dL) |
11.5 (1.6) |
12.2 (0.8) |
11.80 (1.3) |
0.143 |
12.0 (1.1) |
MCV (fL) |
77.7 (12.1) |
80.0 (5.2) |
76.17 (7.7) |
0.89 |
78.2 (7.1) |
Ferritin (µg/L) |
16.5 (18.6) |
54.0 (124.0) |
32.9 (48.4) |
0.106 |
41.9 (93.1) |
sTrfR (mg/L) |
0.23 (0.26) |
0.36 (0.35) |
0.42 (0.76) |
0.791 |
0.38 (0.50) |
BMI: Body mass index, sTrfR: Soluble transferrin receptor; Value
in mean (SD). |
As studies from our subcontinent have been limited on
normal reference ranges for sTrfR levels in pediatric age groups as well
as its utility in diagnosing iron deficiency in inflammatory states, a
higher ferritin cut-off (<30ug/L), as suggested by WHO [3], was used in
this study to define hypoferremic state. Gartner, et al. [5],
have recently highlighted the importance of using a correction factor
for serum ferritin before interpreting the test as a marker for iron
deficiency in obese individuals.
In this study, we noted a high prevalence (60.5%) of
hypoferraemic state in children with high BMI. Studies from West show
much lower prevalence of iron deficiency state in obese children ranging
from 2% to 15.6% [6,7]. This is contrast to studies from Asian
sub-continent, where combined prevalence of ID and IDA is noted to be
around 36-42% [8,9].
Lecube, et al. [10] have highlighted the
importance of sTrfR levels as a better marker for iron deficiency in
obesity due to underlying confounding effect of low grade inflammation
on serum ferritin levels. However, in our study we did not find sTrfR
levels helpful in identifying true hypoferraemic state; sTrfR levels
were within normal limits in 97% cases despite serum ferritin being low.
This could be due to sTrfR levels being affected by variable rate of
erythropoietic activity which could reflect influence of age and
hormonal levels in children being higher as compared to adolescents and
adults. Our study also found a prevalence of anemia to the tune of 28%
in children with high BMI. The anemia was predominantly IDA (65%), while
in 35% cases it was anemia of chronic disease. These findings suggest
that component of nutritional or dietary micronutrient deficiency is
possibly playing a greater role than inflammation-related iron
sequestration in obese children in our population. Another reason could
be the effect of low grade inflammation leading to relatively high
hepcidin levels, which block iron absorption from gut, negatively
affecting the already higher adipose tissue demands for iron.
Acknowledgements: Ms Deepashika, Technician,
Pediatric Hematology Laboratory for estimation of sTrfR.
Funding: Department of Science and Technology,
Chandigarh.
Competing Interest: None stated.
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