The American Thoracic Society recommends race-specific spirometric reference values from the National Health and Nutrition Survey (NHANES) III for clinical evaluation of pulmonary function in whites, African-Americans, and Mexican-Americans in the United States and a correction factor of 0.94 for Asian-Americans. We aimed to validate the NHANES III reference equations and the correction factor for Asian-Americans in an independent, multiethnic sample of US adults.
The Multi-Ethnic Study of Atherosclerosis (MESA) recruited self-identified non-Hispanic white, African-American, Hispanic, and Asian-American participants aged 45 to 84 years at six US sites. The MESA-Lung Study assessed prebronchodilator spirometry among 3,893 MESA participants who performed acceptable tests, of whom 1,068 were asymptomatic healthy nonsmokers who performed acceptable spirometry.
The 1,068 participants were mean age 65 ± 10 years, 60% female, 25% white, 20% African-American, 23% Hispanic, and 32% Asian-American. Observed values of FEV1, FEV6, and FVC among whites, African-Americans, and Hispanics of Mexican origin in MESA-Lung were slightly lower than predicted values based on NHANES III. Observed values among Hispanics of non-Mexican origin were consistently lower. Agreement in classification of participants with airflow obstruction based on lower limit of normal criteria was good (overall κ = 0.88). For Asian-Americans, a correction factor of 0.88 was more accurate than 0.94.
The NHANES III reference equations are valid for use among older adults who are white, African-American, or Hispanic of Mexican origin. Comparison of white and Asian-American participants suggests that a correction factor of 0.88, applied to the predicted and lower limits of normal values, is more appropriate than the currently recommended value of 0.94.