Epidemiology Matters: A New Introduction to Methodological Foundations
Katherine M. Keyes, Sandro Galea
Format: PDF / Kindle (mobi) / ePub
Epidemiology Matters offers a new approach to understanding and identifying the causes of disease -- and with it, how to prevent disease and improve human health. Utilizing visual explanations and examples, this text provides an accessible, step-by-step introduction to the fundamentals of epidemiologic study, from design to analysis.
Across fourteen chapters, Epidemiology Matters teaches the individual competencies that underlie the conduct of an epidemiologic study: identifying populations; measuring exposures and health indicators; taking a sample; estimating associations between exposures and health indicators; assessing evidence for causes working together; assessing internal and external validity of results.
With its consequentialist approach -- designing epidemiologic studies that aim to inform our understanding, and therefore improve public health -- Epidemiology Matters is an introductory text for the next generation of students in medicine and public health.
(given the social stigma associated with smoking), some people may not understand the question, and some people may overestimate or underestimate the number of cigarettes smoked. In general, there will be error in estimating pack-aday smoking. We could, in a subsample of participants, use a blood sample to assess the blood level of cotinine, a biomarker for tobacco smoke exposure. The level of cotinine in the blood increases with exposure to more cigarette smoke, as it is an alkaloid found in
diagnosed in the time period of interest. The denominator is the total size of the population at risk of developing the outcome during the time period of interest. Those who are at risk are the individuals who could conceivably develop the outcome. This excludes people who already have the outcome as well as people who could not possibly develop the outcome. For example, if we wanted to estimate the risk of uterine cancer in a population, whom would we include in the denominator? First, we would
women during pregnancy who are not smokers. We then assess their offspring at age 10 and determine which children developed ADHD and which did not. We assume that there was no loss to follow-up in this sample. Figure 6.5 contains the 2 × 2 table of the results. First, we estimate the incidence proportion of ADHD in this sample. We have a total of 500 children with ADHD out of a total of 10,000 assessed across the exposed and unexposed group. Thus, the incidence proportion of ADHD is
esophageal cancer. 900 How Do Noncausal Associations Arise? 127 Sources of Non-Comparability: Selection and Follow-Up of Study Subjects In Chapter 4, we described three foundational ways in which to take a representative or purposive sample from a dynamically changing population to conduct an epidemiologic study: (a) we can select a sample at a particular point in time, (b) we can select a sample of disease-free individuals and follow them forward in time, or (c) we can select a certain
between smoking and depression by sex would manifest empirically. Shown in Figure 10.12 are hypothetical data from a prospective cohort study on the relation between smoking and depression with each individual in the figure representing 10 people. The population of interest is adults in the general population, and we collect a purposive sample of 80 individuals with no history of depression. FIGURE 10.12 Studying the relation between smoking and depression. 168 E P I D E M I OLOGY M AT T E