TY - JOUR T1 - Area under the expiratory flow-volume curve: normative values in the National Health and Nutrition Survey (NHANES) study JF - Journal of Investigative Medicine JO - J Investig Med SP - 1247 LP - 1257 DO - 10.1136/jim-2021-002057 VL - 70 IS - 5 AU - Octavian C Ioachimescu AU - Kevin McCarthy AU - James K Stoller Y1 - 2022/06/01 UR - http://hw-f5-jim.highwire.org/content/70/5/1247.abstract N2 - The area under the expiratory flow-volume (AEX-FV) loop has been evaluated before as a spirometric tool for assessing respiratory functional impairment. We computed the AEX-FV curves in spirometry tests performed on 20,313 participants in the National Health and Nutrition Examination Survey (NHANES) study.We analyzed 108,939 spirometry tests performed between 2007 and 2012 (5964 children; 14,349 adults). In these tests, we computed the three areas from existing NHANES raw data on instantaneous expiratory flows measured at 0.01 s intervals.Mean best-trial measurements for AEX-FV were 3.4 in boys, 2.8 in girls, 11.8 in men and 7.7 L2/s in women. We characterized indices of central tendency and dispersion of the measurements (eg, means and fifth percentiles—lower limits of normal) by age group (children vs adults), gender, race or ethnicity group and effort grading. Simple regression equations using logarithmic transformations of the above areas and using age, gender and height as inputs provided good predictive ability for the variable AEX-FV.Regular, digital spirometry could and should make available to clinicians and researchers the area under the curves for flow versus volume graph, providing additional tools in our armamentarium to evaluate ventilatory impairments and patterns, and possibly respiratory disability.Data are available in a public, open access repository. Availability of data and materials: yesRef 13:Centers for Disease Control and Prevention (CDC). National Center for Health Statistics (NCHS). National Health and Nutrition Examination Survey Data. https://wwwn.cdc.gov/nchs/nhanes/. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention; 2020. Accessed November 2020. ER -