Breastfeeding, Serum Level of Hemoglobin and Ferritin Associated with the Risk of Asthma in Children: A Case-Control Study

Background: During recent decades, there has been a dramatic increase in the prevalence of asthma in children. There is low-grade quality evidence that breastfeeding and anemia are associated with a reduced risk of asthma in children up to 5 years of age. Objectives: Regarding the high prevalence of anemia and asthma in Iranian children, we aimed to evaluate the risk factors for asthma in children. Methods: The present case-control study examined 110 children (55 cases and 55 controls) aged 3 to 12, admitted to Shahroud educational hospitals from March 2017 to February 2018. The children diagnosed based on the Global Initiative for Asthma criteria, by a specialist physician, were selected as the case group and those admitted to other hospital wards for diseases (such as orthopedic and nephrology), other than respiratory problems were selected as the control group. Multivariable logistic regression was used to find asthma risk factors. P < 0.05 was considered statistically significant. Results: Of 110 children, 63 (57.3%) were boy and mean (± standard deviation (SD)) age of the participants was 7.23 (± 4.17) years and mean weight was 29.6 (± 21.6) kg. Most of the children (76.4%) were fed by breast milk during infancy. Mean (± SD) Hb in the case group was 10.4 (± 2.5) g/dL and in the control group was 11.5 (± 2.3) g/dL (P = 0.01). The prevalence of anemia was 72.7% and 50.9% in the case and control group, respectively (P < 0.001). After controlling for potential confounders, breastfeeding (OR breast milk only vs. formula only = 2.23, P = 0.01), serum level of hemoglobin (OR = 0.13, P = 0.002) and ferritin (OR = 0.32, P = 0.04) were significantly associated with the risk of asthma. Conclusions: Our study found the role of low duration of breastfeeding and ferritin deficiency as a risk factor for development of asthma in children. This finding emphasizes that iron supplementation along with breastfeeding in childhood may prevent asthma and hence reduce the children’s mortality and morbidity rates associated with asthma.