Analysis of spirometric data from a national sample of healthy 6- to 24-year-olds (NHANES II)

The second National Health and Nutrition Examination Survey (NHANES II) incorporated spirometric examinations for a nationwide sample of individuals 6 to 24 yr of age. We analyzed spirometric data on 1,963 healthy, nonsmoking black and white subjects to derive prediction equations for FVC, FEV1, FEV3, PEF, Vmax50, Vmax75, and MMEF. The population was divided into three groups: children (6 to 11 yr of age); teens (males 12 to 20, females 12 to 17 yr of age); and young adults (males 21 to 24, females 18 to 24 yr of age). Using regression analysis, standing height appeared to be the most important predictor of pulmonary function across the entire age group, with the importance of the age variable decreasing in older ages. Controlling for other variables, blacks exhibited consistently lower respiratory function for most measures. This difference increased with age. Male FVC exceeded female FVC after 8 to 9 yr of age; however, female MMEF and Vmax50 performance equaled or exceeded males until approximately 13 yr of age. Males tended to outperform females with the same anthropometric characteristics in all age groups, except in the height range of 130 to 160 cm, where female flows and volumes were superior. Percentile growth curves were also developed to track lung development in clinical practice.