Introduction: Past studies indicate that lung function in professional divers, compared to non-divers, shows a reduction in maximal expiratory flow rates at low lung volumes and a reduction in the transfer factor for carbon monoxide. The objective in this study was to examine possible effects of long-term diving on pulmonary function among Norwegian professional divers.
Methods: The 37 male divers, 24.6 yr (SD = 4.2) at baseline, were examined 4 times during a 12-yr follow-up. The median total number of dives was 503 (range: 40-7054). The effect of diving on pulmonary function was analyzed using linear additive mixed models. The number of dives was used as an explanatory variable. Assessment of lung function included dynamic lung volumes, flows, and transfer factor for carbon monoxide.
Results: The dynamic lung function and the transfer factor for Tl(CO) decreased significantly during follow-up. The observed decline of lung function is mostly due to age. When adjusted for age, follow-up year, smoking status at baseline, height, and weight, the effect of total number of dives on the different lung variables was not significant, except for FEF(25-75%) (L x s(-1)) (P = 0.029).
Conclusions: During a 12-yr follow-up of 37 divers the results show a decrease of lung function, but only expiratory flows at low lung volumes were significantly related to diving exposures.