Poor muscle function is a pressing public health problem: half of all U.S. older adults meet criteria for muscle weakness. Poor muscle function, defined by low muscle strength and power, is a major risk factor for a host of negative health outcomes, including functional limitations, disability, and multimorbidity. Neighborhood characteristics predict functional limitations, disability, and death, but we do not understand the biologic mechanisms.
Muscle function and its underlying physiology, including mitochondrial bioenergetics, are a biologically promising, but unexplored mechanism linking neighborhoods and disability. While previous research has examined neighborhood effects on disability, almost no prior work has explored neighborhood effects on muscle function and no research has evaluated connections with skeletal muscle mitochondria.
Neighborhood factors represent an untapped opportunity in musculoskeletal health research to assess the interplay among environmental, sociocultural, behavioral, and biological determinants to understand and prevent disease while exploring the relationship among mitochondrial biogenesis and musculoskeletal function. Understanding how neighborhood characteristics get under the skin and contribute to poor muscle function, reduced physical activity, and alter mitochondrial bioenergetics will enhance our understanding of what social and biologic risk factors matter most for muscle function and could be targets for interventions.
This study proposal leverages data from two well-characterized datasets, the Health and Retirement Study (HRS) and the Study of Muscle Mobility and Aging (SOMMA) to identify which features of the neighborhood environment are related to muscle function, physical activity and mitochondrial health in older adults. We will assess which predictors of the neighborhood environment affect muscle function in older adults, examine the relationship between the neighborhood environment and skeletal muscle mitochondrial bioenergetics, and test the hypothesis that mitochondrial bioenergetics and physical activity mediate the link between the neighborhood environment and muscle function.
Complementing this research is a detailed training plan that will build on the applicants prior training in social and clinical epidemiology to include (1) neighborhood research on planning/design; (2) the assessment of skeletal muscle mitochondrial bioenergetics, and; (3) causal mediation analysis. This integrated sociobiologic training will prepare the applicant for a successful independent research career focused on incorporating the social determinants of health into the study of musculoskeletal research. Findings from this project will provide critical insights into understanding the complex, multifactorial social and biologic contributors of poor muscle function in older adults.