(PTFS13-04-24) Evaluation of Hemoglobin Cutoff Levels to Define Anemia Among Apparently Healthy 12–23-month-old Children in the United States—NHANES, 1999-2020

Objectives: The study objective was to identify the hemoglobin (Hb) statistical fifth percentile threshold to define anemia among an apparently healthy population of U.S. children aged 12–23 months.

Methods: We used data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2020. The outcome of interest was Hb fifth percentile cutoffs, pooled over 21.2 years of data. Except for the first and last cycles, we combined 4–year survey cycle estimates. We performed weighted univariate percentile ranking to generate Hb concentrations with 95% confidence intervals (CI) among the apparently healthy population, defined by white blood cell in all children, and C-reactive protein and ferritin levels when available. Hb data were not adjusted for elevation. We performed one sample quantile tests to examine differences between the NHANES fifth percentile and current cutoff recommendations, overall and stratified by poverty income ratio and child’s sex.

Results: Of 1800 children analyzed in the overall population, 1041 (58%) were included in the apparently healthy subset (481 girls (46%), 560 boys (54%)). We found that the pooled fifth Hb percentile across survey cycles was 10.80 g/dL (95% CI, 10.66-10.95 g/dL) for the overall population and 10.92 g/dL (95% CI, 10.65-11.19 g/dL) among the apparently healthy subpopulation. The pooled healthy fifth percentile was 11.01 g/dL (95% CI, 10.79-11.15 g/dL) for girls and 10.73 g/dL (95% CI, 10.36-11.00 g/dL) for boys, and not different by child’s sex (p=0.13). The pooled healthy fifth percentile of 10.79 g/dL (95% CI, 10.70-10.99 g/dL) among children in households with a poverty income ratio of 0–1.0 was not different (p=0.54) compared to 10.89 g/dL (95% CI, 10.57-11.14 g/dL) among those in households with a poverty income ratio of >1.0. There was no significant difference between the fifth percentile in the healthy population and the current WHO and CDC recommended cutoff of 11.0 g/dL (p > 0.99).

Conclusions: Current CDC and WHO Hb cutoffs to determine anemia (11.0 g/dL) were not significantly different from the pooled fifth percentile of Hb among apparently healthy young children from 21 years of NHANES data that were not adjusted for elevation.

Funding Sources: None; This study used publicly available data.