Interpreting longitudinal spirometry: weight gain and other factors affecting the recognition of excessive FEV1 decline.

BACKGROUND

Excessive FEV(1) loss in an individual or a group can reflect hazardous exposures and development of lung disease. However, multiple factors may affect FEV(1) measurements.

METHODS

Using medical screening data collected in 1884 chemical plant workers between 1973 and 2003, the influence of multiple factors on repeated measurements of FEV(1) was examined.

RESULTS

The FEV(1) level was associated with age, height, race, sex, cigarette smoking, changes in body weight, and spirometer model. After controlling for these factors, longitudinal FEV(1) decline averaged 23.8 ml/year for white males; an additional loss of 8.3 ml was associated with one pack-year smoking and 5.4 ml with a one pound weight gain. Depending on the spirometer model, FEV(1) differed by up to 95 ml.

CONCLUSIONS

The study results provide quantitative estimates of the effect of specific factors on FEV(1), and should be useful to health professionals in the evaluation of accelerated lung function declines.