Hepcidin and inflammation associated with iron deficiency in childhood obesity - A systematic review

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

INTRODUCTION

Traditionally associated with undernutrition, increasing evidence suggests micronutrient deficiencies can coexist with overnutrition. Therefore, this work aimed to systematically review the associations between iron, zinc and vitamin A (VA) status and weight status (both underweight and overweight) in children and young people.

METHODS

Ovid Medline, Ovid Embase, Scopus and Cochrane databases were systematically searched for observational studies assessing micronutrient status (blood, serum or plasma levels of iron, zinc or VA biomarkers) and weight status (body mass index or other anthropometric measurement) in humans under 25 years of any ethnicity and gender. Risk of bias assessment was conducted using the American Dietetic Association Quality Criteria Checklist. Where possible, random effects restricted maximum likelihood meta-analyses were performed.

RESULTS

After screening, 83 observational studies involving 190 443 participants from 44 countries were identified, with many studies having reported on more than one micronutrient and/or weight status indicator. Iron was the most investigated micronutrient, with 46, 28 and 27 studies reporting data for iron, zinc and VA status, respectively. Synthesising 16 records of OR from seven eligible studies, overnutrition (overweight and obesity) increased odds of iron deficiency (ID) (OR (95% CI): 1.51 (1.20 to 1.82), p<0.0001, I2=40.7%). Odds appeared to be higher for children living with obesity (1.88 (1.33 to 2.43), p<0.0001, I2=20.6%) in comparison to those with overweight (1.31 (0.98 to 1.64), p<0.0001, I2=40.5%), although between group differences were not significant (p=0.08).

CONCLUSIONS

Overnutrition is associated with increased risk of ID, but not zinc or VA deficiencies, with an inverted U-shaped relationship observed between iron status and bodyweight. Our results highlight significant heterogeneity in the reporting of micronutrient biomarkers and how deficiencies were defined. Inflammation status was rarely adequately accounted for, and the burden of ID may well be under-recognised, particularly in children and young people living with overnutrition.

PROSPERO REGISTRATION NUMBER

CRD42020221523.

Associations of Ultrasound Findings with Serum Iron and Ferritin Levels in Children with Obesity

The nutritional status of children is always a concern for medical professionals. Increasingly, obesogenic factors have created a new global epidemic. Obesity is characterized by persistent inflammation, which can have detrimental effects on the growth and development of children. Iron and ferritin are both important factors to consider when evaluating these children due to their role in the pathophysiology of chronic inflammation. Recently, ultrasonographic evaluation seems to be an increasingly used method in pediatric clinical practice. In this study, we included 98 children aged 6-14 years, 72 of whom were obese and 26 had normal weight. The data obtained indicated that there was an association between low iron and increased ferritin levels, aspects of non-alcoholic fatty liver visualized by ultrasonography, and the degree of fibrosis assessed elastographically. Ultrasonography can help us identify liver damage, but the possibility of identifying an association with other paraclinical investigations such as iron and ferritin levels can be cumulative. In this way, the assessment can be more complex, as the child benefits from comprehensive evaluation and management. The results drew attention to non-invasive, easy-to-perform, and low-cost methods of assessing obese children in terms of iron metabolism and structural liver changes.

The Value of an Ecological Approach to Improve the Precision of Nutritional Assessment: Addressing Contributors and Implications of the "Multiple Burdens of Malnutrition"

Globally, children are exposed to multiple health risks associated with diet and nutrition. Rather than simply being a condition of having too much or too little food, malnutrition is more a syndrome comprising multiple burdens of coexisting and reciprocal malnutrition, infection, or other conditions. Importantly, children with such syndromes (e.g., stunting and anemia, which are neither specific nor necessarily sensitive to nutritional status) are more likely to also have irreversible functional outcomes such as poor growth, impaired immune function, or cognitive delays. The global health community has identified nutrition-related targets (e.g., Sustainable Development Goals (SDGs) and World Health Organization (WHO) Global Nutrition Targets) that, for multiple reasons, are difficult to address. Moreover, as the complexity of the global health context increases with persistent pandemics of infectious diseases and the rising prevalence of noncommunicable diseases, there is a growing appreciation that conditions selected as nutrition/health targets indeed represent syndromes for which nutritional status serves as both an input and outcome. In recognition of the impact of these combined challenges and the role of the multiple manifestations of malnutrition, we suggest an approach to nutritional assessment that is intended to improve the precision of context-specific, equitable approaches to health promotion, disease prevention, and treatment.