NIOSH supports exploratory and developmental research projects (R21) that address issues related to diagnostic or treatment uncertainty with respect to individuals receiving monitoring and/or treatment under subtitle B, of the James Zadroga 9/11 Health and Compensation Act of 2010 (Public Law 111347, as amended by Public Laws 114113 and 11659). Enrolled WTC responders and certified-eligible WTC survivors will be included in the research project.Lifestyle medicine is a highly valuable, evidence-informed clinical approach, focused on managing and reversing many of the types of chronic diseases certified as WTC-related health conditions by the WTC Health Program. By focusing on sustainable health behaviors and lifestyle factors (including six pillars: nutrition and diet, sleep hygiene, stress management and positive psychology, physical activity, social connectedness, and avoidance of substance misuse), lifestyle medicine has the potential to limit disease progression; to prevent development of additional chronic diseases; and to improve health outcomes, overall member well-being, quality of life, and member satisfaction with the Program.To establish the scope of the WTC Health Program FY2023 lifestyle medicine research, NIOSH seeks to achieve a suitable mix of projects and interventions focusing on sustainable health behaviors and the lifestyle factors described above. All of these sustainable health behaviors and lifestyle factors influence quality of life, disease progression and recurrence, survival, adverse events, and other health-related outcomes among WTC Health Program members.NIOSH/WTC Health Program R21 grants support the early and conceptual stages of research projects that assess the feasibility of novel areas of investigation, with the potential to enhance the effectiveness of treatment and diagnostic practice. These studies may lead to breakthroughs in a particular area, or to the development of novel techniques, agents, methodologies, models, or applications that have a major clinical impact. These studies should break new ground or extend previous discoveries toward new directions or applications. Applicants are expected to propose research approaches for which there is likely to be minimal or no preliminary data.