DEFINITION and SCOPE OF EPIDEMIOLOGY
Epidemiology is the
study of the distribution and determinants of both disease and injury. Two triads are involved in epidemiology: (a) the agent,
host, and environment triad and the time, place, and person triad. The primary goals of epidemiology are prevention, control,
and, in rare instances, eradication disease and injury. Epidemiology started as a study of epidemics and extended to cover
infectious disease and later non-infectious diseases. It has now become a methodological discipline that is used to study
disease and non-disease phenomena.
CLASSIFICATION OF EPIDEMIOLOGY
deals with qualitative descriptions. Quantitative epidemiology deals with numerical descriptions. Observational epidemiology
is based on observation of human phenomena. Experimental epidemiology involves assessment of the effects of intervention against
a disease phenomenon. Theoretical epidemiology deals with mathematical and methodological issues. Descriptive epidemiology
describes the patterns of disease occurrence in terms of place, time and person. Analytic epidemiology seeks to discover the
underlying causes of diseases.
IMPORTANCE OF EPIDEMIOLOGY
Epidemiology is used
in clinical medicine, public health, and actuarial sciences. The major activities of an epidemiologist are: study design including
selection of the study sample, data collection, data analysis, data interpretation, and initiation of action programs to prevent
disease and promote health. Professional practice and careers in Epidemiology are in government (Ministry of Health), universities,
hospitals, and the private sector (drug manufacturers), and research institutes.
ETHICO-LEGAL ISSUES IN EPIDEMIOLOGYA study involving humans must get approval
from a recognized body. For approval the study must fulfill certain criteria. It must be scientifically valid. It is unethical
to waste resources (time and money) on a study that will give invalid conclusions. Among ethical considerations are: individual
vs. community rights, benefits vs. risks, informed consent, privacy and confidentiality, and conflict of interest. Epidemiologic
study findings affect policy. Epidemiologists must know
how to communicate risk to the public. It is an ethical obligation to report research findings to subjects so that they may
take measures to lessen risk but care must be taken not to raise public anxiety without solid scientific evidence.