Page 48 - Ethical Guidelines for Conducting Research Studies Involving Human Subjects

11. PRINCIPLES OF EPIDEMIOLOGICAL STUDIES

11.1 INTRODUCTION

Epidemiology concern with the pattern of disease that occur in human
populations & the factors influence these pattern. In the earlier years,
epidemiology of infectious diseases was of great importance in Bangladesh,
considering that these were very prevalent. Over the years, infections as a
cause of diseases have diminished in importance as a result of various
measures taken to control these. Improvement in economy and changes in
life styles have contributed to the increase in numbers of non infectious
diseases such as diabetes mellitus, ischaemic heart disease. Many studies
in the western world have demonstrated that epidemiological studies can
identify risk factors contributing to many diseases. This can lead to
adoption of effective public health measures to prevent and reduce the
incidence of these diseases.

Generally Epidemiological studies are in two categories – observational
and non-observational. These studies are mainly based on cross-sectional,
case-control or cohort approaches. Surveillance, programme evaluation and
research are involved in Epidemiological studies. Ethics in epidemiological
studies is multidimensional covering clinical medicine, public health and
the social milieu. The code of ethics in epidemiological studies needs better
understood in clinical research, that ensure the optimum importance
between a clinical researcher and a patient. This aspect needs to be
addressed in preparing a guideline for ethical review of scientific studies in
Bangladesh.

Research in epidemiological aspects of health and disease may involve
large numbers of study participants and may need to be conducted over a
long period of time. In this, these studies differ from clinical trials.
Mistakes or omissions, if not carefully checked for at the beginning, may
create problem when these are detected later. To repeat the whole study
will be wasteful and may not be possible. It is, therefore, essential that all
important aspects such as technical, practical as well as ethical should be
scrutinized carefully at the very beginning of the study.

11.2 DEFINITIONS

Observational Epidemiology: Predefined parameters in a defined
population group over a specified period and frequency are recorded for
finding the risks of exposure that affecting the health known as
Observational studies. These are the following types:

a. Cross Sectional Studies (Surveys): Cross-sectional studies focus
on comparing as well as describing a problem or situation at a point of
time. It is primarily population based study. In this study sample may be
an entire population or randomly selected from the representative

BMRC ETHICAL GUIDELINE ON HUMAN SUBJECTS Page 44