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Evolution of the respiratory function of professional divers over 15 years.

BACKGROUND
The study was aimed at assessing changes in respiratory function after 15 years of profes- sional diving, among scientific divers.


MATERIALS AND METHODS
A retrospective study was performed on divers who underwent an initial visit and a visit 15 years later at the same medical centre, among divers who had a scientific activity (monitoring the coastline, fauna and flora). Pulmonary function tests were performed in the same laboratory with the same operating standards and using a Jaeger MasterBody plethysmograph. Each subject acted as his or her own control. The data were analysed by Student's t-test and Spearman's correlation coefficient.


RESULTS
Twenty-six divers were included. Changes over 15 years included: a decrease in the forced expired volume in 1 second/functional vital capacity (FEV1/FVC) ratio (-6 for absolute value, p < 0.01; and -5% for theoretical value, p = 0.02); a decrease in forced expiratory flow (FEF)25% (-1.1 for absolute value, p < 0.01; and -21% for theoretical value, p < 0.01); a decrease in transfer factor for carbon monoxide (TLCO) (-0.7 for absolute value, p = 0.04); and an increase in vital capacity (VC) (+8% for theoretical value, p = 0.03). A significant correlation was found between the consumption of tobacco in packs per year (PY) and the variations in VC (r = 0.89; p < 0.01) and the variations in the theoretical FEV1 (r = 0.76; p = 0.03). There was a significant relationship between the number of dives and the variations in the percentage of the theoretical FEV1/FVC ratio (r = -0.42; p = 0.04). The same relationship was found for the average of dive duration (r = -0.59; p < 0.01) Conclusions: With increasing length of diving activities service, the pulmonary function displays a trend toward both a decrease in TLCO and a decrease in FEF25%.