EPIDEMIOLOGY : CONTROLLING HEALTH PROBLEMS

- June 02, 2021

Epidemiology is the study of the distribution and determinants of health-related states or events in a specified population and the application of this study is to the control of health problems. Basic epidemiologic methods tend to rely on careful observation and use of valid comparison groups to assure whether what was observed, such as the number of cases of the disease in a particular area during a particular period or the frequency of exposure among persons with disease differs from what might be expected. However, epidemiology also draws on methods from other scientific fields including biostatistics and informatics with biological, economic, social, and behavioral sciences. In fact, epidemiology is often described as the basic science of public health, and for good reason.

First, epidemiology is a quantitative discipline that relies on a working knowledge of probability, statistics, and sound research methods. Second, epidemiology is a method of causal reasoning based on developing and testing hypotheses grounded in such scientific fields as biology, behavioral sciences, physics, and ergonomics to explain health-related behaviors, states, and events. However, epidemiology is not first a research activity but, an integral component of public health, providing the foundation for directing practical and appropriate public health action based on their science and causal reasoning.

Epidemiology is concerned with the frequency and pattern of health events in a population. FREQUENCY not only refers to the number of health events (such as the number of cases of meningitis or diabetes in a population) but also to the relationship of that number to the size of the population. The resulting rate allows epidemiology to compare disease occurrence across different populations. PATTERNS refers to the occurrence of health-related events by time, place, and person. Time patterns may be annual, seasonal, weekly, daily, hourly, or any other breakdown of time that may influence the disease or injury occurrence. Place patterns include geographic variation, urban/rural differences, and the location of work sites or schools.

Epidemiology is also used to search for determinants, which are the causes and other factors that influence the occurrence of disease and other health-related events. Epidemiologists assume that illness does not occur randomly in a population, but happens only when the right accumulation of risk factors or determinants exists in an individual.

Because epidemiology studies can only be conducted after people have been exposed to a chemical, they are not as useful as experimental studies for predicting and preventing adverse health effects:

· Epidemiology studies tend to produce less reliable data that can be more difficult to interpret. For instance, epidemiology studies alone can rarely confirm that particular chemical exposure caused a health effect. Moreover, as noted by Stanford University professor Dr. John Ioannidis, the vast majority of published epidemiology studies are later proven to be wrong.

· Furthermore, except for randomized-control trials that research potentially beneficial therapeutic pharmaceuticals, it is considered unethical to randomly allocate humans into exposed and unexposed groups. So epidemiologists can only observe, not control, the conditions under which people are exposed. Consequently, a vast, unknown number of other variables, referred to as confounders, may cloud our understanding of the relationship between chemical exposure and observed health effects.

· Errors in measurements of exposure and disease also can occur, which can further skew findings. Potential confounding and measurement errors are especially problematic in studies that include a relatively small number of subjects (i.e., less than tens of thousands), report exposures near background levels, and report weaker relationships (increased risks less than 3 fold between groups). Finally, not all epidemiology study designs produce equally strong evidence.

· Epidemiology was originally focused on epidemics of communicable diseases but was subsequently expanded to endemic communicable diseases and non-communicable infectious diseases. By the middle of the 20^th century, additional epidemiologic methods had been developed and applied to chronic diseases, injuries, birth defects, maternal child death, occupational health, and environmental health. Now, with the recent explosion in molecular methods, epidemiologists can make important studies in examining genetic markers of disease risk.

img: google.com

There are some applications of epidemiology:

· Epidemiology is not just the study of health in a population, it also involves applying the knowledge gained by the studies to community-based practice.

· Epidemiology is both – a science and an art. The epidemiologists use the scientific methods of descriptive and analytic epidemiology, as well as experience, epidemiologic judgment, and understanding of local conditions in diagnosing the health of a community and proposing appropriate practical and acceptable public health interventions to control and prevent disease in the community.

All the images are taken from Google.com.

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