NHANES 2015-2018 median heights
About this reference
The FEV1, FVC and FEV1/FVC pages evaluate the GLI-2012 equations at one height per sex and age bracket. That height is the survey-weighted median of measured standing height (BMXHT) for the sex and bracket in NHANES 2015-2016 and 2017-2018 combined, using the 4-year examination weight (WTMEC2YR divided by 2). Age follows the convention of the NCHS anthropometric reference report for the same years (Fryar et al. 2021, Vital and Health Statistics Series 3 No. 46): age at examination for children and adolescents, age at screening from 20 upward. Checked against that report's tables for each year of age from 5 to 19 and each adult age group, every sample size matches exactly and every median agrees within 0.2 cm. FitnessNorms computed these medians from the CDC public examination and demographic files; the derivation script is scripts/derive_spirometry_heights.py in the site's repository.
Known limitations
- An internal FitnessNorms derivation from CDC public microdata, not a table published by NCHS
- One median height per sex and bracket, so the spirometry values on this site describe a person of median height, not any individual
- Adult age is the age at screening, top-coded at 80, so the 80+ bracket pools everyone aged 80 and over
- US population measured in 2015-2018; height distributions differ between countries and over time