chapter 17 Physical Activity Epidemiology Research

Chapter Outline Introduction Physical activity measurement Epidemiologic study designs Reading and interpreting a physical activity epidemiologic study

What is Epidemiology? Epidemiology is “the study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems” (Last 1988, 141). Distribution –Frequency: prevalence, incidence, morality rate –Patterns: Person, place, time Determinants: Defined characteristics associated with change in health Application: Translation of knowledge to practice

Development of Exercise Epidemiology Early studies –Framingham Heart Study –London Busmen/British Civil Servants –Tecumseh Health Study –Harvard Alumni Health Study –Minnesota studies Health People 2010 (U.S. Department of Health and Human Services)

Purposes of Epidemiologic Methods Quantifying the magnitude of health problems Identifying the factors that cause disease Providing quantitative guidance for the allocation of public health resources Monitoring the effectiveness of prevention strategies using population-wide surveillance programs

Key Points in Exercise Epidemiology Observational versus experimental research Key terms in exercise epidemiology –Distribution: frequency and patterns –Determinants Assessment of physical activity –Direct measurements –Questionnaires

Epidemiologic Study Designs Descriptive epidemiology –Cross-sectional designs –Ecological designs Analytical designs –Cohort studies –Case-control studies Experimental designs: randomized trials

Design in Exercise Epidemiology Case-control studies: select participants from a group with a disorder and compare with cases without the disorder Cohort studies –Groups exposed to cause of disorder versus those not exposed: relative frequency of exposure and nonexposure is known –Sample of cohorts selected from population and grouped into cases and noncases

Types of Case-Control and Cohort Designs Retrospective: Look back from effects to potential causes Prospective: Identify an event and follow cases forward form that event for some period Cross-sectional: Measure causes and effects at a certain point and look at relationships