HT Akbayram, M Örkmez

Abstract

Objective: Iron deficiency (ID) is much more common than patients with iron deficiency anaemia (IDA) and the diagnosis of both of these conditions may be quite confusing. The aim of this study is to determine the frequency of anaemia in children with ID and to detect changes between erythrocyte indices. Methods: Data were collected from the electronic database of Gaziantep University Hospital outpatient clinics. A total of 400 children with ID (defined as ferritin levels <15 ng/mL) were included in the study. Results: Four hundred children with ID, 62 (15.5%) showed low haemoglobin (<11 gr/dl), reflecting IDA status. There were positive correlations between ferritin and, haemoglobin, (r=0.42, p<0.01), haematocrit, (r=0.32, p<0.01), mean corpuscular volume, (r=0.33, p<0.01), mean corpuscular haemoglobin, (r=0.40, p<0.01), and mean corpuscular haemoglobin concentration levels (r=0.40, p<0.01), however there were negative correlations between ferritin and red cell distribution width levels (r=-0.45, p<0.01). Conclusion: Erythrocyte indices are helpful markers for identifying ID as the cause of IDA in children.

Introduction

Iron deficiency (ID) is the most frequently nutrient deficiency in the world and is also the main cause of anaemia in children.¹ It is the problem of developed countries as well as developing countries. In developing countries lifestyles, low socioeconomic conditions, and a lack of knowledge of good dietary habits are the reasons for ID.¹ Symptoms of ID are subtle and nonspecific and often only become apparent with severe anaemia.

Several approaches are used to assess the iron status of an individual or of a population. Although the uses of multiple tests are appropriate approaches to assess the iron status of a population, it is less practical and not commonly used in clinical settings. Iron deficiency anaemia (IDA) is more commonly defined with 1-2 indicators in clinical settings; most clinical cases report only anaemia (based on haemoglobin or haematocrit values).The cornerstone of the laboratory identification of IDA is a low haemoglobin and serum ferritin concentration though a normal serum ferritin does not exclude IDA. Serum ferritin concentration has been thought to be a use full index of the status of iron stores.²

ID is a common clinical challenge, but the diagnosis is difficult when erythrocyte indices are normal. The aim of this study is to determine the prevalence of anaemia in children with ID and to detect changes between erythrocyte indices.

Material and Methods The data gathered from our institute Gaziantep University Hospital biochemistry laboratory electronic database. The period of this cross-sectional retrospective study was from 2019 to 2020. Four hundred children were evaluated: 219 females (54.8%) and 181 (45.2%) males. Age of the patients was from 1 to 16 years old. The inclusion criteria were child patients with ID. The haematological parameters were measured using a Sysmex XN1000 analyser. Serum ferritin level was done by Beckman Coulter, UniCel DXI 800 Access immunoassay system. The study protocol was approved by the Medical Ethics Committee of Gaziantep University. There is no consensus in the literature about the cutoff value for low serum ferritin in children.³ We used ferritin cutoff of <15 ng/ml for children to estimate ID since this was a widely used criterion in previous studies.^4,5 World Health Organisation differentiated cut-off criteria for haemoglobin (Hb) by age, sex, and physiological status, it established a single and universal cut-off point of less than 11 g/dl when using Hb for women, infant and children.^6,7 Anaemia was defined as Hb <11.0 g/dl for children in our study. Their red cell indices (mean corpuscular volume [MCV], mean corpuscular haemoglobin [MCH], mean corpuscular haemoglobin concentration [MCHC], and red cell distribution width [RDW]), were below the acceptable level. The following cutoffs were used based on our hospital laboratory values: MCV <80 fL; MCH <26 pg; MCHC <32 g/dl; RDW >14%.

Statistical Analysis Data were analysed using SPSS 23.0 software (SPSS, Inc., Chicago, IL, USA). Demographic data were shown as means and SD or percentages. Categorical variables were compared by using chi-square test. Spearman's correlation analysis was performed to examine the correlations between age and ferritin, and haematological measures. Two-tailed significance values are reported throughout. A probability level of p<0.05 was used to indicate statistical significance.

Results

The sample consisted of 400 children with ID (181 males, 219 females) between 1 and 16 (mean±SD = 8.2±4.1) years. The female-male ratio was 1:0.82. This study group was divided into four groups as group 1, cases <12 ng/ml (n=276), and group 2, cases 12-15 ng/ml (n=124) according to ferritin levels, and group 3, cases <11 g/dl (n=62), and group 4, cases ≥11 g/dl (n=338) according to haemoglobin levels. Table 1 shows demographic characteristics of the subjects.

The mean ± SD of laboratory measures, including ferritin, and haematological values, are summarised in Table 2. Ferritin, Hb, haematocrit (Hct), MCV, MCH, and MCHC were significantly lower, and RDW was significantly higher in group 1. Hb, Hct, MCV, MCH, and MCHC were significantly lower, and RDW was significantly higher in group 3. There was no statistical significant difference between males and females in all measures. There were positive correlations between ferritin and, haemoglobin, (r=0.42), p<0.01, haematocrit, (r=0.32), p<0.01, MCV, (r=0.33), p<0.01, MCH, (r=0.40), p<0.01, and MCHC levels (r=0.40), p<0.01, however there were negative correlations between ferritin and RDW levels (r=0.45), p<0.01. There were no correlations between ferritin and, age. (r=0.093), p>0.05.

Discussion

Iron is an important micronutrient required for body functions. It is also required for mental, motor and emotional development, normal learning processes, and immune maturation. ID and IDA frequently overlap each other and the extent of overlap varies from one population to another and according to gender and age groups.⁸ The present study attempted to assess the association of haematological indices with the prevalence of anaemia among children with ID in tertiary hospital of Gaziantep city, Turkey.

Iron status was associated with IDA in both male and females. Studies suggested that sex-based differences in children are found and are due to the faster growth velocity in males than in females with higher iron requirements.⁹ Also female infants were less ID than males as observed in studies, and these gender-specific differences persisted up to about 3 years of age.^10,11 Adolescents have increased nutritional demands during periods of rapid growth and, in resource constrained contexts, may have low access to nutrient-rich diets. Females are at additional risk for ID and IDA due to the onset of menarche.¹² Akarsu et al¹³ found that ID was mostly observed in girls (53.8%), while IDA were seen predominantly in boys (71 and 62%, respectively). Another a study Keskin et al¹⁴ found that regarding gender distribution of these two systemic conditions, girls were found to be more ID (20.8 vs 17.5%) and IDA (4.1 vs 3.8%) than boys. However, these differences were not statistically significant. Our results revealed that the mean ferritin among females (9.4±3.6 ng/ml) was slightly lower than males (9.5±3.5 ng/ml), also mean Hb among males (9.4±1.7 g/dl) was slightly lower than females (9.7±1.2 g/dl) in the group with IDA. Sex-based differences were not found to exert any significant influence on the Hb and ferritin in 1-16 years old children.

IDA seems to be a public health problem in Turkey. Patients with ID are much more common than patients with IDA and the diagnosis of both of these conditions may be quite. Some patients with ID may have had profound symptoms for many years while their blood count has been normal throughout. ID is the main cause of anaemia, which is the most prevalent nutritional deficiency worldwide, affecting 43% of children worldwide.⁵ In our study, of the 400 children with ID, 62 (15.5%) showed low haemoglobin (<11 gr/dl). Prevalence of IDA was 15.5% in patients with ID. Among school children living in the three largest cities of Turkey, prevalence of ID (ferritin <15 mg/l) and IDA was 19.1% and 3.9%, respectively.¹⁴ Jaber and Diamond found that 11.8% children had low serum ferritin (<12 mg/l). The mean value of Hb was 12.3±0.8 g/dl, and 80 (11.5%) of the children had low Hb. A correlation was found between haematological parameters and Hb. The prevalence of IDA, and ID, was 2.2%, and 11.8%, respectively.⁹ Shanita et al¹⁵ in Malaysia, 8% of the anaemia in 872 children aged 3 to 12 years old was associated with ID (serum ferritin <15 mg/l). Ibáñez-Alcalde et al¹⁶ a cross-sectional study was conducted on a population-based representative sample for teenagers in Spain, of 405 subjects aged 12 to 16 years. ID was present in 13.3% of adolescents, but iron deficiency anaemia only in 1.2%. Zhu et al¹⁷ demonstrated that the prevalence rates of ID and IDA in pre-schoolers, ages 4 to 7 years, were 26.5% and 3.5%, respectively. Another study Akarsu et al¹⁴ in Turkey found that, 12.7% of the anaemia in 557 children aged 4 months to 18 years old was associated with ID (serum ferritin <12 mg/l). The current study revealed a higher prevalence of IDA among 1-16 years old children with ID. The low socioeconomic status of our country is considered responsible for the high rates of patients with impaired iron status and IDA observed in our study population also the worldwide prevalence of IDA has slightly decreased in the past 20 years, but the situation remains concerning in developing countries.¹⁸

Haemoglobin alone is not the best haematological indicator of IDA and cannot be reliably used given all the other known etiologies of anaemia. More effort is needed to directly measure ferritin. It is an inexpensive test and can be performed with a very small amount of blood from a venous sample. In this study found that there were positive correlations between ferritin and, Hb, (r=0.42), p<0.01, Hct, (r=0.32), p<0.01, MCV, (r=0.33), p<0.01, MCH, (r=0.40), p<0.01, and MCHC levels (r=0.40), p<0.01, however there were negative correlations between ferritin and RDW levels (r=0.45), p<0.01. Behera et al¹⁹ assessed the haematological characteristics of 313 children aged 0-12 years. Haematological indicators were measured by standard procedures, which include red blood cell indicators, and plasma ferritin. They found that Hb levels was positively correlated with Hct, MCV, and MCH levels in this population and RDW levels was negatively correlated with Hb, Hct, MCV, and MCH levels. Lippi et al²⁰ also found RDW negatively correlated with Hb and MCV, while inverse relationship of RDW was seen with the Hb in IDA. In our study we also found that IDA patients had significantly lower mean Hb, Hct, MCV, MCH, and MCHC levels as well as significantly higher mean RDW levels than ID (p<0.0001). In another study prospectively evaluated the prevalence of ID and IDA in 256 healthy 18- to 36-month-old children in Northern Israel. There was a significant difference between ID and IDA for Hb and Hct levels (p<0.0001), but not significant difference between MCV, MCH, MCHC, RDW and ferritin levels (p>0.05).²¹ Jaber et al⁹ found that there was no correlation between the Hb and the serum ferritin levels. However, there was a clear correlation between the Hb levels and haematological parameters. There was a significant difference between less than hb 11.5 g/dl and more than 11.5 g/dl for Hct, MCV, MCH, MCHC, RDW levels. Our results revealed that in IDA condition a marked fall in Hb, Hct, MCV, MCH, and MCHC levels and a parallel increase in the RDW were observed. The correlation of different indices is consistent with other studies.^9,19-21

Limitations

In this retrospective study, we do not know about patients whom on iron treatment which could affect the level of serum ferritin and the erythrocyte indices. The present studies were small sample size, and all erythrocyte indices were not analysed.

Conclusion

ID and IDA considered in this study as two different disorders, as IDA has an anaemia with changes in the erythrocyte indices. Erythrocyte indices are useful as biomarkers of ID or IDA. We also found that there were positive correlations between ferritin and, Hb, Htc, MCV, MCH and MCHC levels however there were negative correlations between ferritin and RDW levels.

Declaration of Interest

The authors declare no conflict of interest.

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