Lower respiratory tract infection associated with iron deficiency anaemia

Abstract

Background:
Lower respiratory tract infections (LRTIs) are a leading cause of childhood morbidity and mortality globally, particularly in low- and middle-income countries. Iron deficiency anaemia (IDA), a prevalent nutritional disorder in early childhood, impairs immune function and may increase susceptibility to respiratory infections. This study aimed to evaluate the association between IDA and LRTIs in children aged 1–5 years using objective haematological and biochemical markers.

Methods: A case-control study was conducted at a tertiary care hospital in Rawalpindi from January 2023 to June 2023, spanning a period of six months. Seventy children aged 1–5 years were enrolled, including 35 cases diagnosed with LRTI and 35 age-matched controls without respiratory illness. IDA was defined by haemoglobin <11 g/dL, MCV <75 fL, serum ferritin <30 ng/mL, and serum iron <50 µg/dL. Demographic and clinical data were recorded, and laboratory investigations were conducted. Associations were analysed using chi-square tests and odds ratios (OR), with significance set at p ? 0.05.

Results: IDA was significantly more prevalent among LRTI cases (60.0%) than controls (22.9%) (p = 0.002), with an OR of 5.04 (95% CI: 1.77–14.36). Children with LRTI exhibited significantly lower mean haemoglobin (9.23 vs. 11.58 g/dL), MCV (68.5 vs. 76.3 fL), serum ferritin (21.4 vs. 41.8 ng/mL), and serum iron (36.6 vs. 74.9 µg/dL) compared to controls (all p < 0.001). The association between IDA and LRTI persisted across age, gender, and socioeconomic strata and was strongest among children from lower-income households.

Conclusion: IDA is significantly associated with an increased risk of LRTIs in young children, with affected individuals being five times more likely to develop these infections. Routine screening and early correction of iron deficiency, particularly in socioeconomically disadvantaged populations, may reduce the incidence and severity of respiratory infections in early childhood. These findings support the integration of nutritional interventions into child health and infection prevention strategies.

Keywords: Iron deficiency anaemia, lower respiratory tract infections, children, immune function, case-control study, serum ferritin, public health