IMPAIRED MUSCLE STRENGTH IN FEMALE ADOLESCENTS AND YOUNG-ADULTS SURVIVING LEUKEMIA IN CHILDHOOD

Background. With the improving cure rate in childhood malignancies, increasing interest has been focused on long-term survivors. To evaluate late sequelae of childhood leukemia, the muscle strength of 43 young female survivors was investigated and compared with that of 69 healthy age-matched women. The patients had been off therapy for 1 to 19 years. Methods. The anthropometric characteristics measured were height and weight, and body mass index was calculated. The maximal isometric strengths for elbow flexion, knee extension, and hand grip were measured on a special dynamometer chair. Dynamic muscular endurance was measured by pushup and situp tests. Results. The mean height of the patients was 6.5 cm shorter (P < 0.001) and their mean weight 4.8 kg lighter (P = 0.011) than that of the reference subjects. Muscle strength was in most tests poorer in the patients than in the reference subjects. The differences were statistically significant in elbow flexion and knee extension, and in both muscular endurance tests. There was an association between the maximal isometric strengths and the anthropometric characteristics. Even when allowance was made for the smaller size of the patients, however, they still had less muscle strength than the reference subjects. Of the various treatment modalities, radiation therapy to the cranial area and chemotherapy with L-asparaginase were independently associated with the lower muscle strength values. Conclusions. The muscle strength of female patients may be subnormal for many years after therapy for childhood leukemia. To compensate for these deficiencies, the possible benefits of prophylactic and individually planned exercise should be studied.