In three World Cruise studies lasting 90-106 days, 9-14 % of the crew and 9-16 % of the passenger consultations were because of gastrointestinal disorders [20,36,37], but in the first study , gastroenteritis was included in ‘infectious diseases’, which was the largest group (18% of crew and 12% of passenger consultations).
In a descriptive 1-year study about crew sick leave aboard a cruise ship , 137 crew were isolated for a total of 268 days (= 32% of all sick leave) to prevent spreading of acute gastroenteritis. Out of 7 crew members admitted to ward observation aboard and/or hospitalized in port, 3 cases were related to GI: acute abdominal pain (1) and acute appendicitis (2). Two crew members were referred to gastroenterologists during scheduled vacation at home.
In a study of crew referrals to dentists and medical specialists ashore from three cruise ships during one year, only 10 crew members were hospitalized in port prior to repatriation, of which four were classified as gastrointestinal . All 4 were acute appendicitis, which made this the most frequent reason for hospitalization in port. In earlier years, appendectomy was done aboard when convenient , but ship’s doctors are now only required to have minor surgical skills, according to the Health Care Guidelines for Cruise Medical Facilities, issued by the American College of Emergency Physicians . Most crew referrals to services in port (50-70%) concerned dentistry, reflecting the fact that the ship’s doctors are neither trained nor equipped to do elective dentistry aboard . This study also confirms earlier studies that suggested that seafaring constitute a risk factor for oral health [39,40]. It is in agreement with a large study from 1984 of 201 voyages of Polish cargo ships having doctors aboard: The majority (67%) of all 1868 cases referred for consultation and treatment in foreign ports concerned diseases of teeth, pulp and peri-apical tissue .
In a study from 2 cruise ship in the Caribbean in 1989 and 1990 among 1,360 medically related passenger and crew presentations 9% were gastrointestinal .
A study of 232 passenger consultations aboard an Antarctic cruise ship during the summer season 2004/2005 the most common reason for presentation to the ship’s physician was motion sickness (41%), whereas 6% were listed as ‘gastrointestinal”) .
Peake et al.  evaluated 7.147 passenger consultations on 4 cruise ships during 1 year, of which 8.9% were ‘digestive system diseases’
Inguinal hernia, back pain and accidents were the most common reasons for repatriation from HAL (Holland America Line) ships 2000-2004. HAL provides health care to > 5000 active sea-based crew from all over the world .
Prina et al.  evaluated emergency air evacuation of 104 patients, apparently all passengers, from cruise ships in the Caribbean to Fort Lauderdale. Seventeen evacuations (16%) were because of gastrointestinal conditions (gastrointestinal bleeding 9, infection/peritonitis 3, pancreatitis/cholecystitis 3, hepatitis 1, intestinal occlusion 1), and two of these patients developed complications during the air transport (1 required endotracheal intubation because of respiratory failure following sepsis secondary to diverticular abscesses, 1 sudden hypotension because of gastrointestinal hemorrhage, responding to fluid administration).
In a 1-year study of injuries and diseases on an American oil rig in the Mediterranean 12.2 % of 518 consultations concerned gastrointestinal disorders, mostly acute and chronic gastritis .