Epidemiology has been defined as the study of the distribution and determinants of human health and disease. Both aspects of this definition rely heavily on statistical methods.
To study the distribution of human health and disease, knowledge and proper application of survey sampling methods, as well as questionnaire design, quality control, and database management are needed. Statisticians whose work involves the characterization of the distribution of health and disease typically work for local, state, federal, and international government institutions, such as state and local health departments, the National Center for Health Statistics, and the World Health Organization.
The data collected and analyzed in such efforts are used for the following:
- To calculate state and national cancer incidence rates and track them over time
- To calculate the burden of disease by large groups, such as chronic and infectious, or by smaller groups, such as cardiovascular, diabetes, etc.
- To monitor and report on acute outbreaks of infectious disease, such as HIV/AIDS
- To monitor changes in health-related behaviors, such as cigarette smoking and physical activity
To study the determinants of human health and disease, analytic epidemiologic methods are required. Methods are somewhat different, depending on whether chronic diseases or infectious diseases are under study. The latter group involves mastery of mathematical modeling techniques using differential and difference equations under deterministic and/or stochastic assumptions. The former group involves gathering knowledge and information by relying heavily on biostatistical methods such as logistic regression, Poisson regression, and survival data analysis. Case-control, cohort, and cross-sectional studies are the standard study designs for such endeavors.
Recently, statisticians have been instrumental in moving the entire analytic epidemiology field forward with new work in causal inference, missing data, and measurement error models. Subject matter topics include the following:
- Nutritional epidemiology, such as the study of the relationship, if any, between dietary fat intake and breast cancer incidence
- Environmental epidemiology, such as the study of the relationship between air pollution and its various constituents and overall mortality
- Pharmacoepidemiology, which studies observationally adverse effects and long-term benefits post-market of drugs and devices
Other areas of current interest are social epidemiology where, for example, the association between gender, race, and social class and health are of intense interest, and genetic epidemiology, where genes and gene-environment interactions in relation to health and disease are under investigation. Statisticians whose efforts support the study of the determinants of health typically work for universities, government institutes such as the National Institutes of Health, and, to a lesser extent, consulting firms.
Statistical work consists of directly analyzing and designing studies, advising others on the analysis and design of studies, and developing statistical methods to improve the design and analysis of studies.
If you are interested in learning more about epidemiology, visit the Section on Statistics in Epidemiology.