Epidemiology of lumbar disc lesions in the military in World War II.

A study was carried out in 1095 first Army hospital admissions for lumbar herniation of the nucleus pulposus (HNP) who were individually matched on age and period of service during World War II to holders of Army National Service Life Insurance policies. For both the cases and the comparison group, data were obtained from military records, particularly records of induction into service. Factors showing a statistically significant positive association (p less than 0.05) with admission for HNP in the entire sample and also among enlisted cases matched to enlisted members of the comparison group were: occupation of craftsman or foreman, married status, rural residence, excess height, excess weight, heavy frame, good posture, defects relating to back or legs, military occupation specialty of ground combat, and rank of sergeant or staff sergeant. Factors showing a negative association with admission for HNP in these same groups were: clerical occupation, two or more battle stars earned and officer rank. Essentially the same relationships were found among cases with surgically confirmed diagnoses of HNP, less than 30 years old at hospital admission, and with recent onset of symptoms, when the cases in these groups were compared with their matches in the comparison group. Mechanical factors related to body build as evaluated by height and weight measurements appear to be of significance in the etiology of HNP. Occupational factors also appear to be of importance. Some cases and some controls were hospitalized prior to the first hospital admission of the case for a disease possibly related to HNP. For that time period there were no remarkable differences between cases and controls in service hospital diagnoses, including those of trauma.