The overall goal of this project is to identify signatures of skeletal muscle deterioration in complex diseases. Aim 1 will focus on genetic differences that relate to changes in the metabolome (mQTL) and proteome (pQTL). Which would enable the identification of novel variants as well as deepen our understanding of the impact of synonymous variants. The purpose of aim 2 will be to identify metabolites and proteins associated with skeletal muscle deterioration and progression within complex diseases to expand our knowledge of the underlying mechanisms. Finally, aim 3 will investigate changes in metabolites and proteins associated with the development of complex diseases where skeletal muscle deterioration is common. This would allow for improved risk assessments and potentially improved public health outcomes. This project is estimated to take 48 months to complete and will enable future research into prevention and treatment strategies.