Article Type : Research Article
Authors : Karaagac AT, and Usta SA
Keywords : Congenital heart diseases; Micronutrient levels; Children
Background:
Micronutrients are dietary substances and trace elements necessary for growth,
metabolism, and normal functions of the immune system. Children with congenital
heart diseases (CHD) have increased tendency to malnutrition due to inadequate
intake, altered metabolism, increased oxidative stress, and malabsorption.
Therefore, in this study we planned to compare the micronutrient levels of
children with and without CHD.
Material and Methods:
180 children with CHD and 120 healthy controls, followed in the pediatry and
pediatric cardiology outpatient clinics of Kartal Ko?uyolu Research and
Training Hospital between January 2021 and July 2021, were enrolled in this
prospective study. The children were excluded from the study if they received
iron or vitamin supplements in the last year or if they had any
gastrointestinal malabsorption syndrome. The medical histories of the children
were recorded. Their serum iron, ferritin, vitamin D, folate, zinc and vitamin
B12 levels were analyzed and the results were compared statistically.
Results: The mean age of children was 9.5 ± 4.2 years in the CHD group and 8.6 ± 3.4 years in the control group. Iron, ferritin, vitamin D, folate, and vitamin B12 levels of CHD group were lower than the controls (18.4 ± 8.6 vs 21.6 ± 9.2 µg/dl, 19.4 ± 8.3 vs 22.1 ± 9.8 µg/L, 12.3 ± 5.3 vs 14.2 ± 6.4 µg/L, 3.4 ± 1.9 vs 4.5 ± 2.6 µg/L, 185.4 ± 55.8 vs 255.7 ± 72.8 ng/L, respectively) with a moderately significant statistical difference, but the zinc levels were within the normal limits in both groups.
Conclusion: Children with CHD should be more closely monitored for micronutrient deficiencies and drug supplements should be given when necessary.
Micronutrient is term used to represent essential
vitamins and minerals required in small amounts in diet, but essential to
sustain virtually all normal cellular and molecular functions [1].
Micronutrient deficiency (MND) is only one form of undernutrition. As other
forms of undernutrition are more readily visible, MND is often referred to as
“hidden hunger” [2]. The most common MND exist for vitamin A, folate, iron,
vitamin B12, iodine, and zinc; which may have wide-range negative health
impacts that will ultimately result in death if untreated. The severity,
timing, comorbidities and the extent of the deficiency will determine its
sequelae [3]. Patients with CHD may be more susceptible to the effects of MND
because of increased oxidative stress, impaired skeletal muscle function
(possibly exacerbated by vitamin D deficiency), and impaired myocardial
contraction. Some severe MND can cause heart failure and, therefore, it is
likely that less severe deficiency may exacerbate existing cardiac dysfunction
[4]. Therefore, we planned this study to determine the micronutrient levels of
children with CHD in our follow-up.
A 180 children with CHD (92 females, 88 males) and 120
healthy controls (64 females, 56 males) followed in the pediatry and pediatric
cardiology outpatient clinics of Kartal Ko?uyolu Research and Training Hospital
between January 2021 and July 2021, were enrolled in this prospective study.
The CHD of these children were evaluated by transthoracic echocardiography
(Philips iE33 with 5 MHZ transducer). The exclusion criteria of the study were
not taking vitamin supplements in the last year and not having intestinal
malabsorption syndrome. Medical histories of the children were inquired and the
written consents were received from their parents. Venous blood samples were
obtained from the children and transferred immediately into the tubes without
any anticoagulant agents. The blood cells and plasma samples were separated by
centrifugation (10 min, 3000 rpm). Plasma samples were stored at -20°C, until
serum folate, zinc, iron and vitamin B12 measurements were performed. The
results were evaluated according to the American Academy of Pediatrics (APA)
criteria and were compared statistically. The study was approved by the Ethics
committee of the Institute [5].
The mean age of children with CHD was 9.5 ± 4.2 years and 8.6 ± 3.4 years in the control group. The iron, ferritin, vitamin D, folate, and vitamin B12 levels of the children with CHD were 18.4 ± 8.6 µg/dl, 19.4 ± 8.3 µg/L, 12.3 ± 5.3 µg/L, 3.4 ± 1.9 µg/L, and 185.4 ± 55.8 ng/L, respectively. Despite the higher levels of iron, ferritin, vitamin D, folate, zinc and vitamin B12 levels of the children without CHD (21.6 ± 9.2 µg/dl, 22.1 ± 9.8 µg/L, 14.2 ± 6.4 µg/L, 4.5 ± 2.6 µg/L, 255.7 ± 72.8 ng/L, respectively), the statistical difference was moderately significant. However, zinc levels were within the normal limits (84.5 ± 37.2 µg/dl in CHD group and 85.4 ± 39.2 µg/dl in the control group) and there was no statistically significant difference between the two groups (Table 1).
Table 1: Comparison of the micronutrient levels of the children with and without CHD.
|
Micronutrient levels
|
Children with CHD (n:180)
|
Without CHD (n:120) |
p-value* |
|
Iron (µg/dl) |
18.4 ± 8.6 |
21.6 ± 9.2 |
0.04 |
|
Ferritin (µg/L) |
19.4 ± 8.3 |
22.1 ± 9.8 |
0.04 |
|
Folate (µg/L) |
3.4 ± 1.9 |
4.5 ± 2.6 |
0.04 |
|
Zinc (µg/dl) |
84.5 ± 37.2 |
85.4 ± 39.2 |
0.6 |
|
Vitamin D(µg/L) |
12.3 ± 5.3 |
14.2 ± 6.4 |
0.03 |
|
Vitamin B12(ng/L) |
185.4 ± 55.8 |
255.7 ± 72.8 |
0.03 |
|
*p-value
<0.05 is accepted as statistically significant
|
|||
Statistical Package for
the Social Sciences version 22.0 software was used for the statistical
analysis. Chi-square test was used for categorical data and Mann-Whitney U test
to compare averages in the case and control groups, when necessary. P values
< 0.05 were accepted as statistically significant.
Malnutrition has been implicated in two-thirds of
childhood mortality globally, which has formed the basis of nutritional
management for common childhood illnesses [6]. Despite the growing evidence of
MND in children, nutritional management is still focused mainly on PEM, with
little or no emphasis on micronutrients. Children with CHD are at increased
risk of MND because of their inadequate intake, altered metabolism, increased
oxidative stress and malabsorption as a result of intestinal mucosal edema. In
the present study, the children with CHD were found to have lower micronutrient
levels than the control group with a moderate statistical significance. Morever, the children with CHD have tendency
to have chronic hypoxia and congestive heart failure with a requirement for
anticongestive drugs that may impair appetite, induce anorexia and feeding
intolerance [7, 8]. Anticongestive drugs have been shown to increase urinary
excretion of micronutrients, including thiamine, calcium, selenium and zinc,
while other medications such as angiotensin converting enzyme inhibitors,
angiotensin receptor antagonists and thiazides induce mainly zinciuria and
hypozincemia [9]. Despite using one or more anticongestive therapy, our
patients had moderately low micronutrient levels which could be corrected with
a short period of vitamin and iron supplementation. This may be due to the
close follow up of these patients in our pediatry and pediatric cardiology
outpatient clinics and the increased consciousness of the parents about the
importance of vegetables, fruits, whole grain and meat consumption of their
children regularly [10]. In a recent study involving 41 children with CHD in
Benin, south Nigeria, serum zinc levels were lower in children on diuretic
therapy compared to those not on diuretics, with some of the children having
zinc levels below 70µg/dl [11]. Zinc is involved in monocyte/macrophage
development and regulates its phagocytic functions and cytokine production
[12]. The zinc levels in our study were within the normal limits in both groups
and the statistical difference was not significant. Although we excluded the
children using iron or vitamin supplements in the last year, most of these
children had been given zinc supplementation by their parents in the previous year
either to strengthen their immunity or to increase their appetite.
Micronutrient deficiencies are prevalent among children, but the data on the
magnitude of these deficiencies in children with CHD are insufficient.
Micronutrient supplementation is not regarded as a part of normal protocol in
the management of children with CHD. However, it is crucial to create awareness
of the prevalence of nutritional deficiencies and give drug supplements if
necessary in these children. Well-structured studies should be conducted to
document the magnitude of MND and the effects of micronutrient supplementation
on the clinical, electrocardiographic and echocardiographic parameters in the
children with CHD.