Association of iron deficiency and anemia with obesity among children: A systematic review and meta-analysis.

Introduction: Obesity is a potential risk factor for anemia in children. This systematic review (SR) was undertaken to estimate the association of obesity with iron deficiency (ID) and ID anemia (IDA), in children.

Methods: A systematic literature search for observational studies was done in PubMed, EMBASE, Scopus, and the Cochrane library, with additional hand-searching. Two reviewers independently screened the search output, included eligible studies, extracted data, and assessed study quality using the National Institutes of Health tool. The main outcomes were association of obesity with anemia (IDA), and ID. Secondary outcomes were hemoglobin level, serum iron, ferritin, transferrin receptor saturation, and hepcidin. Meta-analysis was done using a random-effects model. Comparisons were expressed through pooled OR with 95% CI.

Results: Forty-two studies comprising one cohort, 29 cross-sectional, and 12 case-control studies comparing 16,633 children living with obesity and 32,573 children without obesity were included. The pooled OR (95% CI) for ID was 1.64 (1.22, 2.21), 16 studies, 20,949 children; and 0.78 (0.43, 1.43), 17 studies, 40,022 children, for IDA. The pooled prevalence of ID was 20.07% (14.98, 25.16) among children living with obesity (16 studies, 3147 children), compared to 16.1% (11.82, 20.38) in children without obesity. Children living with obesity had significantly lower levels of hemoglobin, iron, % transferrin saturation, and higher levels of ferritin and hepcidin than children without obesity.

Conclusion: There is a significant association between iron deficiency and obesity in children.