Anemia crisis among children in Peru: a scoping review.

Objective: To synthesize the existing literature on the etiologic mechanisms of anemia, challenges in anemia measurement, and diagnostic criteria among children in Peru. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews was followed. PubMed, Web of Science, Scopus, Embase, and the Latin American and Caribbean Health Sciences Literature databases were searched for relevant studies published from 1990 to 2024. Two reviewers independently screened and extracted data from included publications. Etiologic proportions were pooled from heterogeneous studies. Data were analyzed from February 3 to August 1, 2025. Results: The scoping review included 55 studies comprising data on 4 688 221 children. Twenty studies focused on high-altitude populations and 35 on causal mechanisms of anemia, with some studies addressing both; 45 were cross-sectional (82%). Sample sizes ranged from small community studies (9 children) to large nationally representative studies (2 087 768 children). Eight studies did not report sample size. Five studies used existing databanks for spatial analyses or clustering methods to estimate anemia prevalence. Reported causes of anemia according to the findings of individual regional studies were: parasitic infections (53.0%), iron deficiency (14.0%), vitamin B-12 deficiency (13.0%), inflammation (8.0%), folate deficiency (0.2%), and unknown causes (36.0%), although estimates were not directly comparable across studies. Measurement approaches varied, with HemoCue portable hemoglobinometers used in 56.0% of studies. Use of altitude correction formulas was associated with an average increase of more than 30 percentage points in reported anemia prevalence. Conclusions: This scoping review found that anemia in Peruvian children is multifactorial, with regional studies identifying diverse etiologic mechanisms, most commonly parasitic infections and iron deficiency; nationally representative data are lacking. Variability in diagnostic methods, particularly in altitude adjustment, and limited comparability may complicate prevalence estimates. Standardized and validated approaches to anemia assessment are urgently needed to support context-specific interventions and effectively address the childhood anemia burden in Peru.