Ship size as a factor in illness incidence among U.S. Navy vessels

Illness incidence was examined aboard U.S. Navy vessels to ascertain whether sick call rates vary with ship size. Outpatient data from ships of three different sizes (destroyers/frigates, cruisers, aircraft carriers) were surveyed, controlling for geographical region of deployment. Overall rates of illness were lower for the largest ships when contrasted with the smallest vessels for all three operational theaters; these rate differences were significant for the East Asia and Indian Ocean regions. Among major categories of disease, significantly higher rates aboard the small vessels were seen in at least two of the geographic regions for respiratory disorders, digestive diseases, and musculoskeletal problems. Infective and parasitic diseases, skin and subcutaneous disorders, as well as symptoms and ill-defined disorders were significantly higher for small ships in one theater. It was concluded that ship size is a factor in illness incidence and should be considered in medical resource planning.