Fundamental issues in the current and future organization of work, particularly extended work schedules, embrace, directly or indirectly, all American workers and may be related to a number of health outcomes through several intermediate steps. The primary goal of this project is to evaluate at the level of the individual worker the association between exposure to extended work schedules and (a) occupational and non-occupational injury; (b) incident and recurrent psychiatric disorders; (c) incident and recurrent musculoskeletal disorders of the back; (d) incident and recurrent ischemic heart disease; and (e) perceived unhealthy physical and mental status. The secondary goal of this project is to evaluate the association between extended work schedules of the parent(s) and spouse and health outcomes measured at the level of the child and nonworking spouse. The main component of this research project will be designed as a series of case-control studies and case-crossover studies nested within the historical dynamic cohort of US workers identified among the participants in the Household Component of the Medical Expenditure Panel Survey (MEPS HC).MEPS is a continuous, multipurpose, multi-panel survey of the U.S. civilian non-institutionalized population drawn from respondents to the National Health Interview Survey (NHIS). The secondary component of this research project will be a series of case-control studies and case-crossover studies nested within the historical dynamic cohort of nonworking spouses and children of US workers identified among the participants in MEPS HC.Studies within this secondary component will estimate the relation between extended work schedules of the working spouse or parents and health events or health status measured at the level of the nonworking spouse and children. Exposure information in both component of the study will include industry and occupation code, hours worked per week, hours worked per day, start and end times during the day, shift-work, rotating shift, size of business, and self-employment. Health outcomes will be self-reported events that have been validated by information of health care utilization from the care provider. Analyses will be adjusted for a number of possible confounders and effect modifier obtained from MEPS and NHIS including socio-demographic factors, family descriptors and lifestyle factors.