[Adjustment of several spirometric reference equations to a population-based sample in Mexico].
OBJECTIVE
To compare several forced spirometry reference equations used in Mexico in order to know which of them have a better fit to a population-based sample.


METHODS
Spirometric values of 225 healthy subjects 40 years of age or older from Metropolitan area of Mexico City, were compared to several reference equations. The sample is population-based and it was done from June to December 2003. The difference between observed and expected values was calculated. A concordance analysis between both observed and expected values was done and the percentage of subjects under normality lower limit was obtained.


RESULTS
The equations with better fit for FEV1 and FVC were: NHANES III for Mexican-Americans and Euro-Americans; and from PLATINO. Predicted values according to Knudson were lower, and those from Cruz-Mérida, larger than observed values. Percentage of subjects below lower limit of normal was closest to 5% in the reference values from PLATINO.


CONCLUSIONS
We recommend the use of reference values from the study NHANES III (for Mexican-Americans or European-Americans) and PLATINO.
Torre-Bouscoulet
Luis
L
Instituto Nacional de Enfermedades Respiratorias, México, DF. luistorreb2001@yahoo.com.mx
Pérez-Padilla
Rogelio
R
D000328:Adult; D000368:Aged; D003627:Data Interpretation, Statistical; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D017058:Mexican Americans; D008800:Mexico; D008875:Middle Aged; D011237:Predictive Value of Tests; D012016:Reference Values; D013147:Spirometry / Q000706:statistics & numerical data; D014797:Vital Capacity