A case-control study evaluating relative risk factors for decompression sickness: a research report.

BACKGROUND: Factors contributing to the pathogenesis of decompression sickness (DCS) in divers have been described in many studies. However, relative importance of these factors has not been reported. METHODS: In this case-control study, we compared the diving profiles of divers experiencing DCS with those of a control group. The DCS group comprised 35 recreational scuba divers who were diagnosed by physicians as having DCS. The control group consisted of 324 apparently healthy recreational divers. All divers conducted their dives from 2009 to 2011. The questionnaire consisted of 33 items about an individual's diving profile, physical condition and activities before, during and just after the dive. To simplify dive parameters, the dive site was limited to Izu Osezaki. Odds ratios and multiple logistic regression were used for the analysis. RESULTS: Odds ratios revealed several items as dive and health factors associated with DCS. The major items were as follows: shortness of breath after heavy exercise during the dive (OR = 12.12), dehydration (OR = 10.63), and maximum dive depth > 30 msw (OR = 7.18). Results of logistic regression were similar to those by odds ratio analysis. CONCLUSION: We assessed the relative weights of the surveyed dive and health factors associated with DCS. Because results of several factors conflict with previous studies, future studies are needed.