Clustering of recreational divers by their health conditions in a database of a citizen science project.

Divers Alert Network Europe has created a database with a large amount of dive-related data that has been collected since 1993 within the scope of the Diving Safety Laboratory citizen science project. The main objectives of this study are the grouping divers by their health information and revealing significant differences in diving parameters using data mining techniques. Due to the methodology of the project, data cleaning was performed before applying clustering methods in order to eliminate potential mistakes resulting from inaccuracies and missing information. Despite the fact that 63% of the data were lost during the cleaning phase, the remaining 1,169 "clean" diver data enabled meaningful clustering using the "two-step" method. Experienced male divers without any health problems are in Cluster 1. Male and female divers with health problems and high rates of cigarette smoking are in Cluster 2; healthy, overweight divers are in Cluster 3. There are significant differences in terms of dive parameters including pre- and post-dive conditions with respect to each group, such as: exercise level, alcohol consumption, thermal comfort, equipment malfunctions, and maximum depth. The study proves the usefulness of citizen science projects, while data collection methodologies can be improved to decrease potential mistakes resulting from inconsistencies, inaccuracies and missing information. It is hypothesized that if naturally occurring clusters of divers were identified it might be possible to identify risk factors arising from different clusters while merging the database with other dive accident databases in the future.

Risk perception in small-scale fishers and hyperbaric personnel: A risk assessment of hookah diving.

Hookah diving is a fishing method used in many small-scale fisheries in the Gulf of Mexico and the Caribbean Sea, as well as in many coastal fisheries around the world. Many high-value species like sea cucumber and spiny lobster, among others, are harvested via hookah diving. However, the fishing method presents a risk for both decompression illness and carbon monoxide poisoning, both causes of disabilities and death among small-scale fishers, and with significant negative impacts on the social and economic status of households and coastal communities. Currently, there is a misunderstanding among fishers concerning diving risks. Using a mixed-method analysis, this study reports the risk perceptions of small-scale fishers and hyperbaric personnel about hookah diving, and the actual diving accidents which occur in the spiny lobster and sea cucumber fisheries in the Yucatán northeastern ports. The study highlights the need for appropriate fishing technologies and increased awareness among fishers about the consequences of hookah diving. Fishery managers and health services can make priority decisions based on the information generated.

A historical review of the U.S. Navy's busiest recompression chamber in the Pacific theater with a current perspective on caring for civilian divers within its area of responsibility: short communication.

On the island Nation of Guam, the United States Department of Defense has stationed military personnel from every service branch. Guam is utilized as a strategic waypoint for the U.S. military in the Pacific theater. As the largest service branch in the region, the Navy has placed a few Diving Medical Officers in Guam to collectively manage and treat patients with recompression therapy. Guam is also a popular tourist destination, with multiple recreational diving companies certifying individuals who are looking to take advantage of the beautiful warm water and exotic marine life. Unfortunately, with an increase in training and certifying inexperienced divers, came an increase in the operational tempo of the U.S. Navy's recompression chamber on Guam. The recompression chamber on Naval Base Guam (NBG) has been treating patients since 1971. With the only multiplace chamber in the Mariana Islands, Diving Medical Officers, with the accompanying chamber staff, treat military personnel, active-duty sponsored patients and civilian patients. Treating civilian patients by military providers through military treatment facilities presents multiple issues that must be addressed in an effort to provide efficient quality medical care. This article reviews the records, documents, and activity of the NBG chamber over the last four decades. Through the obtained data the information provides projected financial reimbursement from civilian patients. The article also sheds light on areas of needed improvement with regard to data collection, third-party financial collection efforts and the necessity of an inclusive electronic health record (EHR) for military and civilian patients.

The healthy diver: A cross-sectional survey to evaluate the health status of recreational scuba diver members of Divers Alert Network (DAN).

BACKGROUND: Scuba diver fitness is paramount to confront environmental stressors of diving. However, the diving population is aging and the increasing prevalence of diseases may be a concern for diver fitness. PURPOSE: The purpose of this study is to assess the demographics, lifestyle factors, disease prevalence, and healthcare access and utilization of Divers Alert Network (DAN) members and compare them with those from the general population. METHODS: DAN membership health survey (DMHS) was administered online in 2011 to DAN members in the United States (US). Health status of DMHS respondents was compared with the general US population data from the Center for Disease Control and Prevention's Behavioral Risk Factor Surveillance System using two-sided student's t-tests and Mantel-Haenszel chi-square tests. Univariate and multivariate logistic regression analyses were conducted to identify factors associated with healthcare utilization among the DMHS participants. RESULTS: Compared to the general US population, the DMHS population had lower prevalence of asthma, heart attack, angina, stroke, diabetes, hypertension, hypercholesterolemia, and disabilities (p<0.01); more heavy alcohol drinkers, and fewer smokers (p<0.01); and greater access and utilization (routine checkup) of healthcare (p<0.01). Healthcare utilization in males was lower than among females. Increasing age and increase in the number of chronic illnesses were associated with increased healthcare utilization. CONCLUSIONS: DAN members are healthier than the general US population. DAN members also have better access to healthcare and utilize healthcare for preventive purposes more often than the general population. DAN members appear to have a better fitness level than their non-diving peers.

The demographics and diving behaviour of DAN Asia-Pacific members with and without pre-existing medical conditions.

INTRODUCTION: This report examines Diver Alert Network Asia-Pacific (DAN AP) members with and without cardiac or respiratory conditions, diabetes or hypertension and compares their demographics, health and diving activities. METHODOLOGY: Two online cross-sectional surveys of DAN AP members were conducted. The first sought information from 833 divers who applied for membership between July 2009 and August 2013 and who had declared the targeted medical conditions. The second, conducted between December 2014 and April 2015, was sent to 9,927 current members with known email addresses. The groups were compared for age, gender, body mass index, fitness, smoking and diving qualifications, history, currency and practices. RESULTS: Of 343 (41%) respondents to the first survey, 267 (32%) provided sufficient information for inclusion. Of 1,786 (18%) respondents to the second survey, 1,437 (15%) had no targeted medical condition and were included in the analysis. Those with medical conditions were on average 4.7 years older (P 〈 0.001); more overweight or obese (68% versus 57%, P = 0.001); took more medications (57% vs. 29%, P 〈 0.001), smoked less (4% vs. 7%, P = 0.02) and did less repetitive diving (median 75 vs 90, P 〈 0.001). Other diving demographics were similar. CONCLUSIONS: A substantial number of people are diving with medical conditions and there is a need to better understand the associated risks. Divers need to be well-educated about the potential impact such conditions may have on diving safety and should monitor their health status, especially as they age.

Sample size requirement for comparison of decompression outcomes using ultrasonically detected venous gas emboli (VGE): power calculations using Monte Carlo resampling from real data.

INTRODUCTION: In studies of decompression procedures, ultrasonically detected venous gas emboli (VGE) are commonly used as a surrogate outcome if decompression sickness (DCS) is unlikely to be observed. There is substantial variability in observed VGE grades, and studies should be designed with sufficient power to detect an important effect. METHODS: Data for estimating sample size requirements for studies using VGE as an outcome is provided by a comparison of two decompression schedules that found corresponding differences in DCS incidence (3/192 [DCS/dives] vs. 10/198) and median maximum VGE grade (2 vs. 3, P < 0.0001, Wilcoxon test). Sixty-two subjects dived each schedule at least once, accounting for 183 and 180 man-dives on each schedule. From these data, the frequency with which 10,000 randomly resampled, paired samples of maximum VGE grade were significantly different (paired Wilcoxon test, one-sided P ⋜ 0.05 or 0.025) in the same direction as the VGE grades of the full data set were counted (estimated power). Resampling was also used to estimate power of a Bayesian method that ranks two samples based on DCS risks estimated from the VGE grades. RESULTS: Paired sample sizes of 50 subjects yielded about 80% power, but the power dropped to less than 50% with fewer than 30 subjects. CONCLUSIONS: Comparisons of VGE grades that fail to find a difference between paired sample sizes of 30 or fewer must be interpreted cautiously. Studies can be considered well powered if the sample size is 50 even if only a one-grade difference in median VGE grade is of interest.

[Health status, morbidity and injury rate in divers serving in the Kola North].

The authors analyzed the health status of military personnel (males) of the Northern Fleet who did call-up military service (n = 420) and served on contract (n = 1370) in special diving positions in the Kola Arctic over the past few years. For the comparison of the rate of the decline of health level in different conditions of service the authors presented the averaged results of studies previously performed in the same period of time in the service personnel of coastal military units in the European North, troops from the surface ship crews and crew nuclear submarine. In the article there are considered the features of the primary disease and injury. Research and monitoring of causative-consecutive relationships between the features of military professional activity and the level and structure of primary morbidity rate allow to form the main directions of vocational rehabilitation for fleet specialists.

Conservation of the critically endangered eastern Australian population of the grey nurse shark (Carcharias taurus) through cross-jurisdictional management of a network of marine-protected areas.

Between 2001 and 2009, 26 marine-protected areas (MPA) were established on the east Australian seaboard, at least in part, to manage human interactions with a critically endangered population of grey nurse shark, Carcharias taurus. This network is spread across six MPA systems and includes all 19 sites outlined in the National Recovery Plan for C. taurus, though five sites remain open to some forms of fishing. The reserve network has complex cross-jurisdictional management, as the sharks occur in waters controlled by the Australian states of New South Wales (NSW) and Queensland, as well as by the Commonwealth (Federal) government. Jurisdiction is further complicated by fisheries and conservation departments both engaging in management activities within each state. This has resulted in protected area types that include IUCN category II equivalent zones in NSW, Queensland, and Commonwealth marine parks that either overlay or complement another large scaled network of protected sites called critical habitats. Across the network, seven and eight rule permutations for diving and fishing, respectively, are applied to this population of sharks. Besides sites identified by the recovery plan, additional sites have been protected as part of the general development of MPA networks. A case study at one of these sites, which historically was known to be occupied by C. taurus but had been abandoned, appears to shows re-establishment of an aggregation of juvenile and sub-adult sharks. Concurrent with the re-establishment of the aggregation, a local dive operator increased seasonal dive visitation rates at the site fourfold. As a precautionary measure, protection of abandoned sites, which includes nursery and gestating female habitats are options that may assist recovery of the east coast population of C. taurus.

Cardiovascular risk factors and cardiovascular risk assessment in professional divers.

BACKGROUND: The professional diver's activity implies body cardiovascular stress. Little data on cardiovascular risk factors is available. Some studies report a high prevalence of tobacco consumption. The purpose of this study is to investigate the cardiovascular risk factors of professional divers and calculate the predicted 5-year risk and the predicted 10-year risk of an acute coronary event. MATERIALS AND METHODS: In one medical centre, data on dives and cardiovascular risk factors were analysed on Epidata(®) software, by Pearson χ(2) test or by Fisher's exact test, by analysis of variance test or by Kruskal-Wallis test, and by Spearman correlation coefficient. Cardiovascular risk scores at 5 and 10 years were calculated using SCORE. RESULTS: A total 200 professional divers were included. Of these, 31% were smokers or had stopped smoking for less than 3 years; 40% had an abnormal body mass index; 50% had raised total cholesterol levels; 11% had an advanced age; 6.5% had high blood pressure; 81% had at least one risk factor; 66% had an alterable risk factor; 25.5% had a 5-year risk greater than that of the general population of the same age; 2.5% had a high cardiovascular risk at 10 years; and 34% were at intermediate risk. CONCLUSIONS: The majority of divers had at least one cardiovascular risk factor. Cardiovascular risk scores were lower than that of the general population. However, some of this population is at high risk. One third of the divers had an intermediate risk, which should lead to the consideration of conducting additional biological examinations to better assess their risk.

Lower risk of decompression sickness after recommendation of conservative decompression practices in divers with and without vascular right-to-left shunt.

INTRODUCTION: A vascular right-to-left shunt (r/l shunt) is a well-known risk factor for the development of decompression sickness (DCS). No studies to date have examined whether divers with a history of DCS with or without a r/l shunt have a reduced risk of suffering recurrent DCS when diving more conservative dive profiles (CDP). METHODS: Twenty-seven divers with a history of DCS recommended previously to dive more conservatively were included in this study and retrospectively interviewed by phone to determine the incidence of DCS recurrence. RESULTS: Twenty-seven divers performed 17,851 dives before examination in our department and 9,236 after recommendations for conservative diving. Mean follow up was 5.3 years (range 0-11 years). Thirty-eight events of DCS occurred in total, 34 before and four after recommendation of CDP. Four divers had a closure of their patent foramen ovale (PFO). A highly significant reduction of DCS risk was observed after recommendation of CDP for the whole group as well as for the sub-groups with or without a r/l shunt. A significant reduction of DCS risk in respect to r/l shunt size was also observed. DISCUSSION: This study indicates that recommendations to reduce nitrogen load after DCS appear to reduce the risk of developing subsequent DCS. This finding is independent of whether the divers have a r/l shunt or of shunt size. The risk of suffering recurrent DCS after recommendation for CDP is less than or equal to an unselected cohort of divers. CONCLUSION: Recommendation for CDP seems to significantly reduce the risk of recurrent DCS.

Per-capita claims rates for decompression sickness among insured Divers Alert Network members.

Decompression sickness (DCS) in recreational diving is a rare and usually self-limiting injury, but permanent disability can occur. Incidence rate estimates are difficult to establish because the number of divers at risk is usually unknown in population samples with well-documented DCS. We estimated the annual per-capita DCS incidence rates for 2000-2007 based on insurance claims submitted by members of the Divers Alert Network (DAN), Durham, N.C., with dive accident insurance. The overall per-capita DCS claims rate (DCR) was 20.5 per 10,000 member-years. Based on the age-adjusted DCR, males submitted 28% more claims than females. Male-to-female difference was greatest between 35 and 40 years of age and disappeared by the mid-50s. Highest rates were observed in the 30- to 39-year age category, after which DCR declined with increasing age. Highest yearly DCR was estimated in 2002. Insurance dropout rate was greater among those who had DCS in the first year of their insurance compared to those who did not have DCS in their first year.

Triage and emergency evacuation of recreational divers: a case series analysis.

INTRODUCTION: It is unknown if the benefits of rapid treatment always outweigh the risks of emergency evacuation for recreational divers. To investigate current triage practice, we reviewed a three-year consecutive series of evacuations and analyzed the relationship of evacuation completion time (EvCT) to outcome in the decompression illness (DCI) cases. METHODS: Checkbox-keyword searches of calls to Divers Alert Network (DAN) between 4/06 and 2/09 identified cases for review. RESULTS: Of 24,275 calls, 107 were evacuations. Median EvCT, (defined as time from injury to arrival at treatment facility) was 20 hours (mean +/- SD, 27.3 +/- 27.2). Indications were: DCI 56% (60), medical illness 28% (30) or trauma 16% (17). Twenty-five percent of medically indicated evacuations were for pre-existing conditions. One-third of all DCI air evacuations (17 of 51) were for mild cases (pain or tingling only). EvCT and presentation severity were not significant predictors of DCI outcome; however, early data (< 6 hours) was sparse. CONCLUSION: More data are needed assess the benefits of faster evacuations. However, in real-world scenarios with EvCTs in the 20-hour range, time did not influence outcome. Risk-benefit analysis of emergency transport is advised, especially for mild cases of DCI with a low probability of symptom progression.