Body composition and plasma creatine kinase activity.

Plasma creatine kinase (CK) activity and lean body mass (LBM) (by anthropometry) were measured in 120 women (20-82 years) and 70 men (20-82 years). Plasma CK activity and LBM was higher in men than in women. In men plasma CK activity was significantly correlated (product moment correlation coefficient) with LBM and negatively with age. In women plasma CK activity was significantly correlated with age. Partial correlation coefficient calculation showed a significant correlation between plasma CK and LBM both in men and in women. We conclude that in healthy subjects the plasma CK activity is related to LBM, but the LBM is not a major determinant of plasma activity in healthy subjects.