Iron Deficiency Anaemia Is Independently Associated With Pre‐Adolescent Asthma and Not Mediated by High BMI

ABSTRACT The high worldwide prevalence of asthma, obesity and anaemia in the paediatric population is a matter of great concern since it is associated with adverse consequences for physical and mental development. This study aimed to investigate the association between iron status, body mass index (BMI) and asthma in pre‐adolescence. Secondary data analysis of the Healthy Growth Study ( HGS ), a cross‐sectional study representative of 2332 Greek pre‐adolescents (49% boys, median age 11 years). Details of family sociodemographics and asthma were collected via questionnaires. Iron deficiency anaemia (IDA) was defined as transferrin saturation (TS) < 16% and haemoglobin (Hb) levels < 12 g/dL. BMI (kg/m 2 ) was calculated from anthropometric measurements and children were classified as underweight/healthy (UW/HW) versus overweight/obesity (OW/OB) using IOTF cut‐offs. Logistic regression models investigated associations between IDA, OW/OB and asthma. Overall, 24.4% of pre‐adolescents with asthma had ID, and 5% had IDA. The multivariate regression analysis showed that pre‐adolescents with IDA had 2‐fold higher odds of asthma than those without IDA (OR adj : 2.13, 95% CI: 1.08–4.18; p adj = 0.029) after adjusting for children's age, gender, Tanner stage, parents' smoking, region of residence, school economic level, parents' education and family income. BMI did not mediate the association between IDA and asthma. Collectively, our study showed significant positive associations between IDA and asthma in Greek pre‐adolescents. Longitudinal studies are recommended to validate and generalise our findings, as well as investigate the biological pathways underpinning these conditions. Meanwhile, health professionals could consider screening for IDA in paediatric asthma patients. Early intervention could successfully reduce the burden of both conditions and their associated longer‐term health complications.