Corresponding Author: Anja Petaros, MD, Department of Forensic Medicine and Criminalistics, Rijeka University School of Medicine, Brace Branchetta 20, 51 000 Rijeka, Croatia. E-mail: firstname.lastname@example.org
The aim of the study was to retrospectively analyze diving fatalities occurring in Primorje-Gorski Kotar County (northern Croatian littoral), Croatia between 1980 and 2010 in order to identify differences between fatally injured tourist and resident divers, as well as temporal changes in the frequency of diver deaths.
Medico-legal and police reports of 47 consecutive fatal diving cases were reviewed to determine the frequency of death among divers in relation to year and month of death, age, sex, nationality, organization of diving, diving type, and health condition.
The majority of victims were foreign citizens (59.6%) most of whom fell victim to scuba diving (70.4%). It was found that 79% of resident divers succumbed during free-diving. The number of diving fatalities increased significantly in the last three decades, especially among free-divers. Of the victims, 93% were males, usually belonging to younger age groups with tourist divers being significantly older than local divers. And 31.9% of divers, mostly tourists, showed signs of acute, chronic, or congenital pathological conditions.
Fatally injured foreign divers differ from resident diver fatalities in diving method and age. Tourists are the group most at risk while scuba diving according to the Croatian sample. Occupational scuba divers and free-divers are the group most at risk among resident divers. This study is an important tool in uncovering the most common victims of diving and the related risk factors. It also highlights the problems present in the legal and medical monitoring of recreational divers and discusses possible pre-event, event, and post-event preventive actions that could lead to reduced mortality rates in divers.
Underwater diving has become one of the most popular and widespread water sports. The search for new and attractive diving areas, the development of commercial means of travel, and the availability of diving locations and centers has turned diving into a widespread tourist activity.
Currently, two types of diving are cited: diving with secured physiological breathing conditions (scuba diving and surface supplied diving) and diving without secured physiological breathing conditions (breath-holding/free-diving/skin-diving). A second classification distinguishes recreational (snorkeling, spearfishing, scuba diving for sport, and leisure), from occupational/professional diving (eg, military diving, scientific diving, police diving). Another important category of divers are technical scuba divers who dive both for pleasure and professional reasons, but descend to greater depths, or use different mixture of gases. There are certain risks involved in practicing the sport, because when the body is immersed in water it is exposed to non-physiological conditions with a limited oxygen supply and elevated ambient pressure.[2, 3] Even though diving is a relatively safe sport, the growing number of divers [over 500,000 newly PADI (Professional Association of Diving Instructors) certified divers worldwide each year] is causing an increase in the number of accidents at sea, with 16 diver deaths per 100,000 persons reported annually. Although drowning is the most common direct cause of death in divers,[5, 6] it is triggered by different events, such as problems with equipment, insufficient gas supply, loss of consciousness, nitrogen narcosis, unfavorable sea conditions, trauma, preexisting diseases, and stress/anxiety. Along with drowning, death in divers can result from decompression sickness/embolism, pulmonary barotrauma, natural causes, or mechanical injuries.[1, 5]
Although tourists make up the largest portion of the diving community,[8, 9] studies on the involvement and differences in fatal diving incidents between tourist and resident divers are lacking in literature. Collecting such data and following the trend in diving fatalities in a region can be important for both tourist management and the development of specific risk control strategies. Therefore, the aim of this article is to offer a retrospective analysis of fatal diving incidents in the Primorje-Gorski Kotar County (northern Croatian littoral) of Croatia between 1980 and 2010 in order to determine the demographic characteristics of diving casualties and their secular trend with special emphasis to differences between local divers and tourists.
Medico-legal aspects of death in divers were investigated through a retrospective analysis of autopsies carried out at the Department of Forensic Medicine and Criminalistics, Rijeka University School of Medicine, Croatia between 1980 and 2010. The Department has universal coverage over the territory of two counties, the Primorje-Gorski Kotar and Lika-Senj. The Primorje-Gorski Kotar County, with a population of 300,000 people, encompasses part of the northern Croatian littoral with its islands, and is home to many interesting diving points, which makes diving accidents and fatalities more susceptible in this area. The analysis covered a period of 31 years (1980–2010) and included a total of 47 consecutive cases of diver deaths. The necessary pathological and biological data were retrieved from medico-legal reports and death certificates, while data regarding the circumstances and conditions which resulted in the fatal outcome were retrieved from police reports of the Ministry of Internal Affairs, Primorje-Gorski Kotar County. The variables analyzed in this study included the biological profile of the victims (age and sex), the year and month of death, type of diving (scuba diving/ free-diving), diving organization (diving in a group or alone), nationality of the diver (resident or tourist), and presence of any preexisting pathological condition in the victim. The deaths were analyzed by calculating the frequency of their occurrence with regard to specific variables. While investigating temporal changes in the frequency of diving fatalities, the studied period was divided into three decades and two major periods: before and after the year 1996, that is considered to be the year that diving tourism in Croatia took off. Variations between the groups and the frequencies were analyzed with a difference test between the two proportions and a Mann–Whitney test. Results of p < 0.05 were considered statistically significant.
In the period between 1980 and 2010, a total of 47 deaths in divers were registered. Most of the victims in the study were male (44/47, 93.6%). The victims fall into the young and middle-aged age group, with the majority of them between 20 and 29 years (28.3%), and 30 to 39 years (28.3%) (Table 1). The mean age of victims was 38.1 (range 10–72). Most of the victims were diving at sea, while one diver died in fresh water during a speleological expedition (2.1%).
Table 1. Frequency of diving fatalities according to the type of diving and age group
Age group (years)
In the group of free-divers, one victim belonging to the 10–19 years group and one to the 70–79 years group were snorkeling at time of death.
The data refer to those divers where the type of diving is known (for one person this information is missing).
The information on the type of diving was missing for one victim. The number of victims in scuba diving and free-diving does not differ [23 (50%) vs 23 (50%)]. Out of 22 scuba diving fatalities, 3 (6.7% of the total diving accidents) occurred while performing a technical dive (at depths greater than 60 m or during occupational and/or speleological diving). In the group of free-divers, two cases (4.3%) involved snorkelers and included the youngest (a 10-year-old girl) and the oldest (a 72-year-old man) victim. The age groups of victims in the two categories differ in that the majority of scuba divers belong to the age group of 30 to 49 years (34.8%), while most free-divers are young adults [20–29 years (19.6%)] (Table 1). However, there is no significant difference between the mean ages of the victims belonging to the two groups.
Data about the organization of the diving were available in 40 cases. Most free-divers were diving alone at the time of death (16/20, 80%), while scuba divers were always diving in pairs or in a group (20/20, 100%).
Out of 47 victims, 28 were tourists (59.6%), mostly coming from Germany (7 victims), Austria (4 victims), Czech Republic (3 victims), France (3 victims), and Italy (3 victims). A significant difference (p = 0.002) in diving styles was discovered between foreign and local divers: while foreign divers were most commonly victims of scuba diving (19/27, 70.4%), residents died during free-diving (15/19, 78.9%) (Table 1). Only four deaths of Croatian scuba divers were recorded and of these, three (15.8%) were casualties of technical and occupational dives. A significant difference (p < 0.001) in age was observed between tourists and local victims, tourists being older than Croatian victims (mean age of tourists was 44 years, while for residents it was 29.3 years). Most of the fatal diving incidents occurred in the summer months (38.9% locals vs 60.7% tourists). All female victims in the sample were tourist divers.
The number of diving-related deaths has grown with every decade. From 1981 to 1990 there were 8 causalities, from 1991 to 2000 17 casualties, and from 2001 to 2010 22 diving casualties (Figure 1). While the number of casualties due to scuba diving shows stagnation during the last decade, the number of free-diving casualties has continued to rise (Figure 1).
During the last three decades, the number of tourist casualties has risen faster than the number of Croatian diver casualties (Figure 2). The difference is most notable when examining the number of diving-related deaths before and after 1996. After 1996, the rise of tourist casualties (5 tourists before 1996 and 23 tourists after 1996) is greater than that of local divers (6 Croatian divers before 1996 and 13 after 1996).
The most common cause of death was drowning (42/47, 89.4%), followed by decompression sickness (2/47, 4.3%) and barotrauma (1/47, 2.1%). Two divers died of natural causes (heart failure and heart attack) (2/47, 4.3%). All the divers who died from natural causes and decompression sickness were tourists. Some of the drowning victims died because of unfavorable sea conditions [high waves (2/42, 4.8%)], while others owing to underwater obstacles disabling the diver from ascending to the surface (concrete blocks, shipwreck) (4/42, 9.5%), and one diver died of drowning after being hit by a speedboat (1/42, 2.4%). Even though it was not the direct cause of death, another drowning victim showed signs of decompression sickness and embolism that probably triggered drowning (1/42, 2.4%).
A section of the divers suffered from a preexisting health problem while engaged in diving. Fifteen victims (31.9%) showed signs of acute, chronic, or congenital diseases. In six divers more than one pathologic condition was found (6/15, 40%). The pathology ranged from heart and blood vessel diseases (12/15, 80.0%; myocarditis, pericarditis, severe atherosclerosis, congenital narrowness of the aorta, hypertrophy, etc.) to lung diseases (3/15, 20.0%), renal diseases (4/15, 26.7%), and hepatic diseases (2/15, 13.3%). Preexisting health-disrupting conditions were found in 10.5% of resident divers and 46.4% tourist divers. Alcohol intoxication was absent from all recorded victims, except for the oldest victim who drowned during snorkeling.
The study evidenced a continuous increase of diving-related deaths in the studied regions, especially among free-divers. The majority of victims were foreign citizens (59.6%) most of whom fell victim to scuba diving (70.4%). Seventy-nine percent of resident divers succumbed during free-diving. The victims usually belonged to younger age groups with tourist divers being significantly older than local divers; 31.9% of divers, mostly tourists, showed signs of acute, chronic, or congenital pathological conditions.
Even though diving has a small overall mortality and accident rate, the growing number of divers and the development of diving tourism have caused a volume-related increase in the number of diving injuries and deaths. Such trends have also been recorded in the Primorje-Gorski Kotar County where the numbers of diving-related deaths, especially of tourists, show a continuous increase during the 31-year period, with 46.8% of the deaths occurring during the last decade (2001–2010).
Although in Croatia there is no law that fully regulates diving activities, up to now activities related to scuba diving have been normatively controlled directly or indirectly by a number of regulations and articles scattered in different laws.[11, 12] These do not include regulations on free-diving activities, in turn making scuba diving a better monitored and controlled underwater activity. In accordance with this, even though the number of diver-related deaths in Primorje-Gorski Kotar County is increasing, scuba diving-related deaths have remained stable, while free-diving deaths continue to increase (Figure 1). Although free-diving is a sport independent from diving operators, a regulative reform that would encompass and monitor free-diving activities should be mandatory.
Licensing/relicensing of divers as well as the standardization of diving education is the second important point that needs to be addressed when discussing pre-event preventive measures. Although scuba divers must be certified in order to practice the sport, the necessary prerequisites and the training offered to future divers differ significantly between clubs.[9, 13] Before undertaking diving certification, a future diver should obtain proper medical clearance. Unfortunately, not all diving schools request a formal medical examination,[1, 14] while non-professional free-divers are completely outside of medical supervision. Studies have proven the presence of preexisting pathologic conditions in a significant portion of fatally injured scuba divers which may have triggered the fatal outcome or were the direct cause of the diver's death.[9, 15, 16] In our sample, 31.9% of victims (10.5% of resident divers and 46.4% tourist divers) had preexisting pathologic conditions that affected mostly the cardiovascular system. Although not directly associated to the cause of death, the presence of such conditions marks the need for regular health check-ups that are often omitted once the diver has a regular diving qualification.[9, 13] They should be provided especially to risk-group tourists who occasionally practice diving and to older divers, as psychophysical abilities gradually decrease with age.[1, 9] We propose that divers undergo a medical examination before travelling to a diving destination. Given that most of the pathological conditions in our sample were found in divers older than 40 years (data not shown), regular annual health check-ups or even a relicensing should be planned for this age category, as well for occasional divers in order to ascertain their level of health, fitness, and skills. Attention should also be given to the medical screening of possible asymptomatic preexistent diseases and to young divers with acute health conditions which they often underestimate.
Diver education in different countries should meet a homogenized set of international guidelines so as to ensure a uniform level of knowledge for all parties participating in diving. A large number of divers from continental states learn to dive in swimming pools and lakes in their respective countries, and are therefore not adequately prepared for diving at sea. Our data show that tourists make up 59.6% of the total number of diving-related deaths and that the majority of them came from continental cities. Apart from this, tourists are often offered “quick” diving courses in the countries they are visiting that do not prepare divers appropriately for a timely response to unanticipated underwater events. Our study showed that the two cases of decompression sickness, a condition that can be a result of inadequate preparation for a dive, were recorded in tourists. Yet, the education of scuba divers is more regulated than that of free-divers, who often do not have any formal education and are thus more prone to fatal accidents.
Dive planning, organization, and preparation (including site selection) are other important factors that should primarily depend on the diving industry and which, if done correctly, can lower the overall mortality rate among divers. Evaluating a diver's preparedness and health status before a dive should not be left to the divers' self-assessment; rather it should be objectively assessed by the dive operator.[13, 18] Substances, like alcohol and medications, which can limit proper reasoning underwater should be avoided. In our sample, no substance abuse was present in fatally injured scuba divers, but alcohol intoxication was present in one free-diver (snorkeler). Although snorkeling is not being perceived as a harmful activity, people practicing it must be aware of the possible fatal consequences that can result from an unconscionable conduct prior and during the activity. Another important factor that has to be taken into consideration, especially when organizing a dive on one's own, is the possibility of unfavorable weather conditions (they resulted in two fatal accidents in our sample). Dive briefing should be given to all divers prior to a dive, and with special attention to tourists. It is important for them to get acquainted with the geographical, maritime, and climatic conditions of the diving site, possible hazards (underwater obstacles, dangerous caves, and sea current) as well to be accompanied by a local diver guide who is familiar with the area.
Proper education of divers is crucial in the event of an underwater incident so as to enable the divers to react promptly in unexpected situations. When inexperienced divers are diving in a group, they may endanger the victim and all the other members of the group, in the event of a diving injury.[22, 23] On the other hand, diving with a group of trained divers ensures better reactions to possible accidents and access to emergency medical care. This is why it is important for recreational divers to dive in pairs, be trained in recognizing and dealing with disrupted health conditions, and for this practice to be extended to free-divers. Data in this study proved that free-divers have fatal accidents while diving alone, most commonly during underwater fishing activities. The fact that they had been diving alone and had not logged their dive led to an untimely response of the rescue team and prolonged the search and recovery of the body (data not shown).
Lastly, post-event activities that could reduce accident risks must be performed. They should include an effective surveillance system of divers and a detailed investigation of every diving accident including an autopsy, equipment testing, an evaluation of the diving plan, and data on the practical/theoretical experience of the divers involved, allowing us to better recognize risk factors and the population most at risk. In the Croatian sample, the majority of victims were foreign citizens (59.6%), most of whom fell victim to scuba diving (70.4%); this is in contrast to resident divers who succumbed during free-diving (79%). The greatest number of scuba diving fatalities among locals was related to professional and technical diving. Similar data were also recorded in the southern part of Croatia, Split-Dalmatian County. The higher ratio of foreign citizens in the overall number of deaths, and their significant rise after 1996, can be explained by the substantial ratio of foreign divers in the country, especially in the post-war period when diving tourism in Croatia took off (unofficial data report that the number of foreign divers is rising at an annual rate of 15%–20% and that they make up almost 80% of the reported divers[12, 26]). The striking difference in diving styles among locals and tourists can be explained by economic and cultural factors which induce a greater number of Croatian divers to practice free-diving for leisure while participating in scuba diving for professional reasons. In addition, fatally injured foreign divers are often people who start to participate in the sport later in life when they have achieved financial autonomy and mobility (as scuba diving is a financially demanding sport). Being significantly older than local divers, they have a greater number of preexisting pathologies that could easily trigger a fatal outcome.
The main limitation of the study was the inability to clearly establish the population at risk (the exact number of divers in the county) due to the lack of a continuous systematic monitoring system of scuba divers during the 30-year period. The number of free-divers is unknown and impossible to estimate as their activity is not controlled by law or regulations. However, the existing data document a continuous increase in the number of divers in Croatia, the number rising from 42,000 in 2001 to more than 60,000 by the end of the decade (with approximately 14,000 divers and 25,000 dives reported in Primorje-Gorski Kotar County in 2009). Despite this limitation, the systematic collection and analysis of data regarding diving accidents in the Primorje-Gorski Kotar region has shown that there is a need for stricter monitoring of diving tourism, regular health check-ups for senior divers and, most importantly, a legally regulated monitoring and education system for free-divers.
Today, modern diving can be, in every sense, equated with diving tourism. Therefore, its risk-prevention strategies should also represent a fundamental segment of research in the fields of travel medicine and tourist management, as nothing short of an interdisciplinary cooperation at national and international levels will guarantee the effective management of diving risk factors in the future.
The authors would like to thank Igor Mijolović for the significant assistance in collection of data regarding the type, conditions, and organization of diving. The authors would also like to thank the two anonymous reviewers for their comments and suggestions which helped to strengthen and improve this manuscript.
Declaration of Interests
The authors state that they have no conflicts of interest to declare.