In brief
Epidemiology
Epidemiology is a branch of medicine that deals with the study of disease in population, the incidence, distribution, and ways to control the same.Centres of disease control and prevention (CDC) explains epidemiology as a scientific and systematic data-driven study of the distribution and determinants of health-related states and events in specific populations and application of the same information for control of health problems. So, we see that epidemiology consists of three aspects: –
- Identification of disease patterns in a population,
- Identify causes or associated conditions and
- Provide data for prevention, control, and treatment of the health condition.
Biostatistics
Biostatistical analysis is the science and art of dealing with variation in data to get reliable results and conclusions. Application of statistics to any field of medicine or health is biostatistics.
Biostatistics in epidemiological studies
Epidemiological studies are heavily dependent on biostatistics. Epidemiological statistical services convert data and information got from epidemiological studies, analyse it, and convert it into forms that help solve issues related to public health. Biostatistical services use quantitative methods to combine the two disciplines of epidemiology and biostatistics.
How do we know the risk factors associated with heart disease? How did we conclude that there is no one cause for this but a combination of genetic and lifestyle factors that increase the risk to have a coronary event? This understanding is thanks to the famous Framingham Heart Study which is still underway. Here, over 5000 volunteers agreed to be followed up for several decades to help public health workers understand the risk factors associated with heart disease.
As the world is struggling today to understand and curtail the pandemic of Covid-19, the role of epidemiology in public health has never been clearer. Biostatisticians are using statistics to predict how the pandemic will behave, spread, and the mortality rate.
Thus, epidemiology and biostatistics are the basic sciences of public health.
Steps in epidemiological biostatistics
Steps involved include: –
- Address a public health question – generate a hypothesis
A hypothesis in epidemiology is an assumption based on
- Scientific rationale
- Observation or anecdotal evidence
- Results of prior studies
- Conduct a study –
- Survey – studies extend of health condition in defined population
- Surveillance – Monitors or detects health condition. It can be done actively or passively.
- Observational – study the association between an exposure and a health condition. Here, there is a natural distribution of the control and study group.
- Experimental – study involving exposure, treatment, and disease outcome.
- Collect data – numerical facts and figures, observations that are obtained from the investigation. Data must be reliable and accurate for reliable and significant outcomes.
- Describe the observations / data – by descriptive statistical methods, the data is assessed descriptively and organised in graphs, tables, and other summary methods.
- Assess strength of evidence for or against the hypothesis – Inferential statistics does a confirmatory data analysis. The strength of evidence is assessed, comparisons are made with previous studies and predictions are made. It also provides future questions and areas of future research.
- Make recommendations based on inferences – The study proves or disproves or is inconclusive on the hypothesis. The study may be published in peer-review publication or may be spread by any other suitable medium of communication. The outcome may be a regulatory or policy change in handling a health condition or a change in behaviour of the people.
Epidemiology and biostatistics services together provide valuable inputs on study design, disease modelling, sampling, surveillance, analysis, risk stratification, identification of vulnerable populations and prevention, control, and treatment of the health condition in the population. Biostatistics helps in designing study methodology, data models that are epidemiologically relevant to make information and data more informative by adequate analysis.
Biostatistical tools
Most studies use observational and descriptive statistics in the form of tables and graphs are most used. There are several biostatistical computerised tools that are available today that make the process automated. Of these, SAS and STATA are the most used packages. Other packages used are SUDAAN, SPSS, R, ARCGIS, HLM, IVEWARE, BUGS etc. Logistic regression is the most common classical statistical technique used.
Biostatisticians
Biostatisticians are the ones running the show for Statistical Programming Services. They usually have a master’s degree or a doctorate in statistics, some also have a degree in public health. They often have a background in mathematics or computer science. They are the ones who help make sense of the complex data that comes out of the study. They help link the cause and effect and solve the mystery of causation vis-à-vis association between the exposure and disease condition.
The road ahead
Biostatistics is the backbone to study epidemiology public health, and it needs to be included adequately in medical curriculum. Medical professionals need to understand biostatistical tools better to be able to interpret and use public health statistics in their practice. Several courses in statistical methods are available online for working medical professionals seeking additional training.
And so
Epidemiology and biostatistics are two sides of the same coin and together they form the backbone of the public health information system. Strong biostatistical support turns scientific data into information that help epidemiologists and governments plan strong public health policies.
References
- Park K. Textbook of preventive and social medicine. 21st ed. BanarasidasBhanot; 2011.
- Mahajan BK. Methods in biostatistics. 7th ed. New Delhi: Jaypee Brothers Medical Publishers; 2010.
- Bhuyan, Dhrubajyoti&Dua, Neha & Kothari, Tejal. (2015). Epidemiology and biostatistics: Fundamentals of research methodology. Open Journal of Psychiatry & Allied Sciences. 7. 10.5958/2394-2061.2015.00022.1.
- Sundaram KR, Dwivedi SN, Sreenivas V. Medical statistics principles and methods. New Delhi: BI Publications; 2010.
- Villeneuve, P.J., Paradis, G. &Muhajarine, N. Always better together: the Canadian Journal of Public Healthand the Canadian Society for Epidemiology and Biostatistics. Can J Public Health 111, 305–307 (2020). https://doi.org/10.17269/s41997-020-00362-x
- Hayat, M. J., Powell, A., Johnson, T., &Cadwell, B. L. (2017). Statistical methods used in the public health literature and implications for training of public health professionals. PloS one, 12(6), e0179032. https://doi.org/10.1371/journal.pone.0179032
