Diverse Abnormal Body Composition Phenotypes: Interaction Between Muscle, Fat, and Bone

Sarcopenia, obesity, and osteoporosis, the three disorders of body composition, are growing in prevalence. Osteoporosis and obesity were thought to be mutually exclusive conditions, as were sarcopenia and obesity. However, these disorders are commonly observed in the aging process and recent studies have indicated a potential interconnection among them with interaction between muscle, bone, and fat. Therefore, it would not be appropriate to discuss sarcopenia, obesity, and osteoporosis without bearing in mind the complex interactions of muscle, fat, and bone tissue. Due to the complicated interaction among them, the phenotypes have been given various names depending on the proposed cause or the combination of sarcopenia, obesity and osteoporosis. Therefore, we introduce new terms concerning the diverse phenotypes of body composition. In addition, this paper describes the interaction between muscle, fat and bone from a hormonal aspect and in terms of the whole body. Unraveling the link between muscle, fat, and bone at both the micro and macro level will elucidate the reasons for abnormal body composition phenotypes, and further enhance new therapeutic options for sarcopenia, obesity, and osteoporosis.