Pulmonary Function in Wood Workers Exposed to Formaldehyde: A Prospective Study

Abstract

Employees exposed to formaldehyde in the woodworking industry (N = 47) and nonexposed control subjects (N = 20) were examined in 1980 by spirometry and the nitrogen washout technique. A transient impairment of lung function was noted over a work shift. Five years later, 21 subjects were still experiencing exposure to formaldehyde. A transient decrease in lung function was again found over a work shift, as evidenced by a reduction in forced mid-expiratory flow (FEF_25–75) of 0,15 l/s and an increase in closing volume (CV%) of 3.0% in nonsmokers. Significant decreases in forced expired volume in 1 s as a percent of forced vital capacity (FEV_1.0/FVC) and FEF_25–75 were also noted over the 5 y in nonsmokers (0,4% and 0,2 I · s/y, respectively, after correction for normal aging). After 4 wk of no exposure (holidays), FEF_25–75 and forced expired vital capacity (FVC, FEV_1.0) returned to normal in the smoking group. Lung function in smokers improved less during the holiday. A dose-response relationship was found between exposure to formaldehyde and decrease in lung function. Thus, industrial exposure to formaldehyde causes transient lung function impairment over a work shift, with a cumulative effect over the years. The impairment, however, can be reversed with 4 wk of no exposure.