Cigarette Smoking and Decompression Illness Severity: A Retrospective Study in Recreational Divers

Buch DA, El Moalem H, Dovenbarger JA, Uguccioni DM, Moon RE. Cigarette smoking and decompression illness severity: a retrospective study in recreational divers. Aviat Space Environ Med 2003; 74:1271–1274.

Background: Severe decompression illness (DCI) could be more likely in cigarette smokers because of airway obstruction or vascular disease. The present study evaluated the severity of DCI as a function of cigarette smoking in recreational divers. Methods: We examined all DCI reports recorded in the Divers Alert Network (DAN) database from 1989 through 1997. Smoking history was quantified as heavy (>15 pack-years), light (0 to 15 pack-years), and never smoked. DCI symptoms were classified as severe (alteration in consciousness, balance or bladder/bowel control, motor weakness, visual symptoms, convulsions), moderate (other neurological symptoms), or mild (pain, skin, or non-specific symptoms). The proportional odds model and generalized logits were used for the adjusted analysis when accounting for other covariates. Results: There were 4,350 patients included in the analysis. After adjustment for confounding variables, heavy smokers were more likely to have severe vs. mild symptoms than nonsmokers (OR = 1.88) (95% CI 1.36,2.60) or light smokers (OR = 1.56) (95% CI 1.09,2.23). Heavy smokers and light smokers were more likely to have severe vs. moderate symptoms than nonsmokers (OR = 1.36) (95% CI 1.06,1.74) and (1.22) (1.02,1.46), respectively. Although these data do not reveal whether smoking predisposes to DCI, the results are consistent with a tendency, when DCI occurs, for cigarette smoking to trigger more severe symptoms. Conclusions: The data suggest that when DCI occurs in recreational divers, smoking is a risk factor for increased severity of symptoms.