Anthropometric Markers and Iron Status of 6–12-Year-Old Thai Children: Associations and Predictors

Abstract

Introduction. Obesity may be associated with poor iron status. The objective of this study was to investigate the association between different indices of iron status and anthropometric measurements in Thai children. Materials and Methods. Anthropometry (weight, height, waist circumference (WC), and body composition assessed by bioelectrical impedance analysis) and iron indices were measured in 336 Thai children aged 6–12 years. Iron deficiency (ID) was defined using two or more of the following: (1) %transferrin saturation (%Tsat) < 16%; (2) serum ferritin (SF) < 15 μg/mL; and (3) soluble transferrin receptor (sTfR) > 5 mg/L. Iron deficiency anaemia (IDA) was defined as haemoglobin < WHO age cutoff combined with ID. Overweight and obesity were defined as body mass index (BMI) standard deviation score (SDS) ≥ +1 SDS or +2 SDS, respectively (WHO growth reference). Results. BMI SDS was significantly positively correlated with sTfR and SF (sTfR, r: 0.209, p < 0.001; SF, r: 0.214, p < 0.001) and negatively correlated with %Tsat (r: −0.132, p = 0.013). Correlations between WC SDS and %fat mass and each iron marker were similar. The percentage with low SF was significantly lower than that using other individual markers. ID prevalence was not significantly different between normal-weight and overweight/obesity groups although a significantly higher proportion of overweight/obese children had sTfR >5 mg/L. Puberty and menarche were significant predictors of ID (puberty adjusted OR: 2.20, 95% CI: 0.43, 11.25; menarche adjusted OR: 6.11, 95% CI: 1.21, 30.94). Conclusion. Greater adiposity was associated with poorer iron status. However, SF may not be a good indicator of iron status in Thai children, particularly in those who are overweight/obese, whereas sTfR merits further investigation.

Overnutrition is a risk factor for iron, but not for zinc or vitamin A deficiency in children and young people: a systematic review and meta-analysis

“…In 2020, the WHO revised their guidance on the use of ferritin to assess iron status in individuals and populations, providing thresholds of <15 µg/L for healthy individuals above 5 years of age and <70 µg/L for individuals with infection or inflammation (<12 µg/L or <30 µg/L are used for children under 5). While current WHO guidance is that ferritin, both an iron storage protein and an acute phase reactant associated with inflammation,43 should not be used alone to diagnose ID without other iron profile biomarkers or corrections for inflammation,44 a minority of studies did rely on ferritin alone 25 45–48. Likewise, serum iron alone should not be used in isolation to diagnose ID as serum iron levels will be reduced in the context of infection or inflammation,49 but was used in a handful of studies 43 50 51.…”

“…Inflammatory status is particularly relevant as ferritin, the primary blood biomarker of iron status used, was consistently found higher in obese groups compared with children with normal weight, with direct linear association reported in multiple studies 25 46–49 56 66 85 98–105. However, as ferritin is an acute phase reactant, inflammation can obscure ID106.…”

Exploring the complex dynamics of BMI, age, and physiological indicators in early adolescents

“…Boys experienced muscle growth and changes in BMI as they grew. Studies have found that transferrin receptors increased with BMI [ 35 ], and obese individuals had higher levels of soluble transferrin receptors compared to overweight and normal-weight individuals [ 36 ]. Obesity is associated with chronic inflammation due to the production of pro-inflammatory molecules by adipose tissue.…”

Association between Child Nutritional Anthropometric Indices and Iron Deficiencies among Children Aged 6–59 Months in Nepal

“…The public health effects of iron deficiency include reduced work capacity and mental performance, poor growth development, impaired regulation of body temperature, impairments in behaviour and intellectual performance, and decreased resistance to infections [ 13 , 14 ]. Previous studies on the association between different indices of iron status and anthropometric measurements have reported that greater adiposity was associated with poorer iron status, which was demonstrated by lower serum iron (SI) and %transferrin saturation (%Tsat) and higher total iron-binding capacity (TIBC) and soluble transferrin receptor (sTfR) [ 15 ]. Overweight/obese children were also reported to require higher iron intake to maintain their iron homeostasis [ 15 ].…”

“…Previous studies on the association between different indices of iron status and anthropometric measurements have reported that greater adiposity was associated with poorer iron status, which was demonstrated by lower serum iron (SI) and %transferrin saturation (%Tsat) and higher total iron-binding capacity (TIBC) and soluble transferrin receptor (sTfR) [ 15 ]. Overweight/obese children were also reported to require higher iron intake to maintain their iron homeostasis [ 15 ].…”