
>A review of fatalities among insured DAN Members also provided some interesting insights, particularly regarding associations with the age of the diver.2 Annual death rates for insured DAN Members were stable during 2000-2006, with a mean of 16.4 deaths per 100,000 members. Fatality rates increased dramatically with age. Among divers 15-25 years of age, the fatality rate was less than 10 per 100,000 members but increased to 30 per 100,000 among divers 65 years of age and older.
>Women under the age of 55 were much less likely to die while diving than were men, but among divers 65 years of age and older, there was no difference in the death rate between the sexes.
>To better understand the specific role of age in these deaths, we went back to the associated injury data and this time looked at the trends by dividing members into two age groups: over 50 and under 50. In this analysis, we found that older divers were three times more likely to die from asphyxia; four times more likely to die from AGE and 13 times more likely to die from cardiac events than the under-50 dive group.
>The high association of cardiac incidents with older divers is of particular concern since the general diving population is aging. As a result of our findings, DAN Research has planned a two-and-a-half-day workshop for April 2010 to discuss the question of dive fatalities.
>Analysis of the DCS claims among DAN Members from 2000 to 2007 found an average rate of 217 cases per 100,000 insured members, with an annual decrease in claims of approximately 12 cases per 100,000 members during the period. The claims rate was very low for divers in their early teens, rose to 350-400 cases per 100,000 members for divers in their 20s and declined with age thereafter. For women, the claims rate was lower than for men by about 60 DCS cases per 100,000 members.
>In future columns, we plan to bring you updates from ongoing DCI/DCS research projects including:
- a joint effort between DAN Research and DAN Medical Services to investigate first aid and therapy options that provide the best long-term outcomes for divers affected by DCI the collection of depth-time profiles from recreational and technical divers to study the overall DCS incidence and identify profiles with the highest DCS probability
- the establishment of a center of excellence for DCS probability modeling in cooperation with Duke University's mechanical engineering department and the U.S. Navy.
- how immersion and exercise affects the DCS risks of flying after diving
- how elevated oxygen partial pressures affect carbon dioxide narcosis
- a recently completed study that found the prescription drug Cialis increased the risk of CNS oxygen toxicity in rats.3
>1. Denoble P, Caruso J, Dear G, Pieper C, Vann R. "Common causes of open-circuit recreational diving fatalities." Undersea Hyperbar Med. 2008; 35(6):393-406.
>2. Denoble P, Pollock N, Vaithiyanathan P, Caruso J, Dovenbarger J, Vann R. "Scuba injury death rate among insured DAN members." Diving and Hyperbaric Medicine. 2008; 38(4):182-8.
>3. Demchenko I, Ruehle A, Allen B, Vann R, Piantadosi C. "Phosphodiesterase-5 inhibitors oppose hyperoxic vasoconstriction and accelerate seizure development in rats exposed to hyperbaric oxygen." J Appl Physiol. 2009; 106:1234-42.