The sickle cell trait in relation to the training and assignment of duties in the Armed Forces: I. Policies, observations, and studies.

Opinions differ widely concerning the risks assumed by individuals with sickle cell trait (SCT) while engaged in military activities that involve exposure to hypoxic environments and other stress situations. Some claim that there is no scientific evidence of greater risk to those with SCT than to those without it, and that any and all restrictions are unfounded and unjust. Others believe that the success of military missions with the least possible risk to the health and safety of individuals are major concerns and that restrictions on the selection, training, and assignment to duties are necessary. Clinical observations indicate that in vivo sickling of erythrocytes in individuals with the SCT may occur in association with cardiac, pulmonary, and other primary diseases. Past scientific investigations have been inadequate and the conclusions drawn have been conflicting. Future policies will be based on information from new investigations combined with facts revealed in the literature and from retrospective studies of the experiences of those with and without the SCT while on duty in the Armed Forces.