Epidemiology

Classical epidemiology
Hippocrates already noted that environmental and personal factors could contribute to disease occurrence “Whoever whishes to investigate medicine properly should proceed thus: in the first place to consider the season of the year, and what effects each of them produce. …and the mode in which the inhabitants live,.., whether they are fond of drinking water and eating to excess, and given to indolence, or are fond of exercise and labor”.

These observations have formed the foundation for the first basic assumption of epidemiology, namely that disease does not occur at random, but that certain factors contribute to disease occurrence. The second fundamental assumption of epidemiology evolved many centuries later, namely that causal factors of disease could be identified through comparison of groups of ill people with groups of healthy people.

Modern epidemiology
The 20th century witnessed a rapid evolution of epidemiological techniques and methodology. Specific methods of collecting and analyzing data were developed using descriptive, case-control, cohort and experimental study designs.  Clinical medicine started applying epidemiological methodology. It addressed etiological issues but also began to focus on questions of diagnostic procedures, treatment and prognosis. This further progressed to the establishment of ‘evidence –based medicine’ approach to respond better to the needs of patients..

Where epidemiology was originally solely a discipline to solve public health problems, it has thus evolved more and more into an indispensable widely applied research discipline. The epidemiological concepts and methods, its reasoning and its approach for collecting and judging the significance of observation and data, is nowadays practiced in all kinds of health research.