[Meaning in measurement of bone mineral content as preoperative evaluation of aged patients].

Recently, mean span of life has been prolonged, and extensive operations are performed on aged patients. However, there are cases which have a difference between their chronological and actual ages. Bone mineral content (BMC) decreases with age and the decrease in BMC might suggest deterioration of immunological competence as observed in osteoporosis. Whether BMC can be an index for evaluation of geriatric patients' actual age from the aspect of immunological competence was investigated. Subjects were 54 cases aged more than 60. Twenty-one healthy young males and females were enrolled as the control group. Quantitative CT is used for assessment of BMC. The value obtained by dividing BMC by the standard BMC of the same age and sex, was defined as BMC index. BMC indices of normal BMC group were more than 0.8 and those of decreased BMC group were less than 0.8. Some immunological markers were investigated. Lymphocyte subset OKT3+ was reduced and juvenile lymphocytes expressed by OKT6+ and OKT3+-(OKT4+ + OKT8+) increased (corrected). Increased in juvenile lymphocyte and decrease in lymphocyte blast transformation and competence of generating interleukin 2 were observed in decreased BMC group. BMC is useful as preoperative evaluation for geriatric operative cases and patients of BMC index below 0.8 need to be paid attention to postoperative infection.