Age changes of skeletal muscle by cross-sectional CT image

In CT images at the 4th lumbar vertebra level in 58 males and 59 females from young male students to elderly inpatients, body composition and muscle density were measured and age related changes were analyzed. The following results were obtained. Body composition: In males, the bone and muscle layer was the largest followed by the abdominal cavity and subcutaneous fat layer in this order in students (20s) three layers were nearby equal in young adults (20s and 30s) and in middle age (40s and 50s). In the elderly inpatients (80s and 90s), the subcutaneous fat layer was lowest. The changes according to age in females were similar to those in males. Muscle cross-sectional area: In females, age changes were milder than those in males and slight decreases in the female elderly inpatients were similar to males. Muscle density: In young adult males, low density changes increased slightly in students and were more pronounced in the middle age group. In the elderly inpatient group, marked low density changes were found in all muscles. (author)