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About this objective
Data
National baseline: 82.6 percent of non-pregnant women aged 15 to 44 years had optimal red blood cell folate concentrations in 2013-16
National target: 86.2 percent
Methodology
Methodology notes
RBC folate concentration is a population weighted estimate from the blood specimens collected from women aged 15 to 44 years as part of the standard NHANES protocol. According to data from NHANES, median RBC folate concentrations increased substantially between 1988-94 and 1999-2000, pre- and post-fortification with folic acid, and then declined slightly in the post-fortification period (Pfeiffer et al., 2007, CDC, 2007).
Design changes were made to the August 2021-2023 NHANES cycle to minimize in-person contact during the COVID-19 pandemic. Refer to the Data Source page for more information. Unlike previous cycles, there was no oversampling of Hispanic, non-Hispanic Asian, and non-Hispanic Black persons and persons with family incomes <185% of the poverty threshold. This may result in lower confidence in the estimate and insufficient power to detect differences between groups. In addition, seventeen percent of interview participants had missing family income data.
Reference: See Ogden et al. for more discussion about estimates by race and ethnicity using August 2021–August 2023 NHANES data: Ogden CL, Emmerich SD, Stierman B, Chen T-C, Simon AE, Freedman DS, et al. Obesity among children and adolescents in NHANES August 2021–August 2023: An examination of race/Hispanic origin subgroup estimates. Pediatr Obes. 2025 Oct;20(10):e70041. DOI: https://onlinelibrary.wiley.com/doi/10.1111/ijpo.70041
History
Footnotes
1. Effect size h=0.1 was chosen to correspond with 10% improvement from a baseline of 50%.