Applying inappropriate cutpoints leads to misinterpretation of folate status in the U.S. population1–5

Details

• Alternative Title:
  Am J Clin Nutr
• Personal Author:
  Pfeiffer, Christine M. ; Sternberg, Maya R. ; Hamner, Heather C. ; Crider, Krista S. ; Lacher, David A. ; Rogers, Lisa M. ; Bailey, Regan L. ; Yetley, Elizabeth A.
• Description:
  Background ; Folate cutpoints for risk of deficiency vs. possible deficiency were originally derived differently (experimental vs. epidemiologic data) and their interpretation is different. Matching cutpoints derived from one assay with population-based data derived from another assay requires caution. ; Objective ; We assessed the extent of folate status misinterpretation using inappropriate cutpoints. ; Methods ; In the cross-sectional NHANES, serum and red blood cell (RBC) folate were first measured using a radioproteinbindingassay (RPBA, 1988–2006), then using a microbiologic assay (MBA, 2007–2010). We compared prevalence estimates for assay-matched (e.g., using RPBA cutpoint with RPBA data) and assay-mismatched (e.g., using MBA cutpoint with RPBA data) cutpoints for risk of deficiency based on megaloblastic anemia as a hematologic indicator in persons ≥4 y e.g., <7 nmol/L serum folate, <305 nmol/L RBC folate, derived by MBA, possible deficiency based on rising homocysteine as a metabolic indicator in persons ≥4 y (e.g., <10 nmol/L serum folate, <340 nmol/L RBC folate, derived by RPBA), and insufficiency based on elevated risk of neural tube defects in women 12–49 y (e.g., <906 nmol/L RBC folate, derived by MBA). ; Results ; Pre-folic acid fortification (1988–1994), risk of deficiency for assay-matched vs. assay-mismatched cutpoints was 5.6% vs. 16% (serum folate) and 7.4% vs. 28% (RBC folate); it declined post-fortification (1999–2006) to <1% vs. <1% (serum folate) and <1% vs. 2.5% (RBC folate). Pre-fortification (1988–1994), risk of possible deficiency for assay-matched vs. assay-mismatched cutpoints was 35% vs. 56% (serum folate) and 37% vs. 84% (RBC folate); it declined post-fortification (1999–2006) to 1.9% vs. 7.0% (serum folate) and 4.8% vs. 53% (RBC folate). Post-fortification (2007–2010), risk of insufficiency was 23% (assay-matched) vs. 39% (assay-mismatched). ; Conclusions ; Applying assay-mismatched cutpoints leads to misinterpretation of folate status. This likely applies to clinical assays as no comparability data are available.
• Keywords:
  • NHANES
  • deficiency
  • insufficiency
  • microbiologic assay
  • radioproteinbindingassay
  • Adolescent
  • Adult
  • Child
  • Child, Preschool
  • Cross-Sectional Studies
  More +
• Source:
  Am J Clin Nutr. 104(6):1607-1615
• Pubmed ID:
  27680995
• Pubmed Central ID:
  PMC5693380
• Document Type:
  Journal Article
• Funding:
  001/WHO_/World Health OrganizationInternational/ ; CC999999/ImCDC/Intramural CDC HHSUnited States/
• Volume:
  104
• Issue:
  6
• Download URL:
  https://stacks.cdc.gov/view/cdc/49925/cdc_49925_DS1.pdf
• File Type:
  [PDF - 116.24 KB]
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:88cbacf8fd3fb4d746fee89467a2ff1626af55675def1cc3cc640d241aad96f3