Linking anemia to asthma: maternal, childhood and adult perspectives from a meta-analysis of 20 studies

Anemia has been implicated as a potential risk factor for asthma across different life stages, yet evidence remains inconsistent. This meta-analysis (CRD420251008733) aimed to evaluate the associations between maternal anemia and offspring asthma, childhood anemia and asthma, and adult anemia and asthma. We searched PubMed, Embase, Web of Science, and Cochrane Library, identifying 20 observational studies. Study quality was assessed using the Newcastle-Ottawa Scale (NOS) and Agency for Healthcare Research and Quality (AHRQ) checklist. Heterogeneity, sensitivity, and publication bias were explored through subgroup analyses, sensitivity tests, and Egger’s test. Meta-analysis performed using Stata 17. Twenty studies involving over 4499364 participants were included. The results showed pooled OR for the association between anemia and asthma (OR = 1.55, 95% CI: 1.36–1.77). Maternal anemia during pregnancy was associated with a modest increase in offspring asthma risk (OR = 1.19, 95% CI: 1.02–1.38), adult anemia was also linked to asthma (OR = 1.94, 95% CI: 1.14–3.30). Childhood anemia showed a stronger association with asthma (OR = 2.22, 95% CI: 1.65–2.99), though Egger’s test (<i>p</i> = 0.041) suggested publication bias, with an adjusted OR of 2.03 (95% CI: 1.51–2.74). Anemia is significantly associated with an increased risk of asthma, particularly in children. These findings suggest a potential role for anemia screening in asthma management.