title: The relationship of decongestant use and risk of decompression sickness; a case-control study of Hawaiian scuba divers.
abstract: Exposure to cold, dehydration, and aging are known to contribute to the development of decompression sickness (DCS) in divers. Hypertension and nicotine usage have also been suggested as risk factors. Vasoconstriction is an underlying mechanism associated with all of these risk factors. Vasoconstriction increases the degree of bubble formation which is believed to be the cause of DCS. Formed bubbles interfere with the production of nitric oxide which modulates vascular tone resulting in vasoconstriction. Divers commonly use sympathomimetic decongestants which induce vasoconstriction to prevent barotrauma of the ears and sinuses while diving and thus theoretically may contribute to the risk for developing DCS. The purpose of this case-control study was to explore the association between decongestant usage and development of DCS in 400 divers treated/evaluated at the University of Hawai'i, John A. Burns School of Medicine between 1983 and 2010. Bivariate and logistic regression analyses were employed to evaluate differences between cases and controls. In addition to the variable of interest, other co-variables known to have significant influence in the development of DCS were appropriately controlled for during the analyses. In this study population, dehydration (OR = 2.7; 95% CI: 1.1, 7.4), repetitive diving (OR = 2.8; 95% CI: 1.8, 4.4), and violation of dive profiles (OR = 4.9; 95% CI: 3.1, 7.9) contributed independently and significantly to the development of DCS. The co-variables of cold, gender, obesity, and rapid ascents were not significant contributors to developing DCS in this study. There was a small but statistically insignificant risk associated with decongestant use (OR = 1.4; 95% CI: 0.8-2.6; P = .22). The inherent limitations associated with records-based studies may have underestimated this risk. It is important therefore that future research be undertaken to help clarify this concern.
authors.affiliation: Hyperbaric Treatment Center, University of Hawai'i, John A. Burns School of Medicine, Honolulu, HI.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Smerz
mesh_terms: D000293:Adolescent; D000328:Adult; D003665:Decompression Sickness / Q000453:epidemiology* / Q000209:etiology; D004242:Diving / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006254:Hawaii / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult
keywords: Decompression sickness; decongestants; diving health; epidemiology of diving accidents; safety