Aseptic bone necrosis among U.S. Navy divers: survey of 934 nonrandomly selected personnel

Nine hundred thirty-four U.S. Navy divers were selected and surveyed radiographically using standard techniques developed for detecting aseptic bone necrosis (ABN). X rays were read by qualified radiologists. A total of 16 positive cases was detected, and another 11 were interpreted as doubtful. ABN was found to be related to age and number of months in diving. After controlling for these factors, ABN could not be related to any of seven indices of diving activity. Divers with ABN did, however, have a history of more treatments for decompression sickness (DCS) than did divers without ABN. Implications of these findings are discussed, and the suggestion is made that ABN and DCS may not be related causally, but may be related to a third common factor. The need for controlled studies is discussed. The conclusion is made that the low prevalence rates of ABN among U.S. Navy divers cannot be related to any specific index of diving activity, and may not be causally related to DCS.