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Is an applied branch of statistics is very heavily utilized for medical research methodology.
Concerned with the presentation , organisation and summarization of data
Are used to generalize the data from sample to a larger group of patients
(through the bioengineering of bacteria and algae).
Thus biostatistics as a science of figures can tell
Application of Biostatistics
APPLICATION OF BIOSTATISTICS
This session covers :
Basis of Biostatistics
Applications of Biostatistics
Previous year Questions
It is the science which deals with
collection, classification and tabulation of
numerical facts as the basis for explanation,
description and comparison of phenomenon.
O It is the branch of statistics concerned with
mathematical facts and data related to
O It is the science that helps in managing
O Biostatistics covers applications and contributions not
only from health, medicines and, nutrition but also
from fields such as genetics, biology, epidemiology,
and many others.
O It is mainly consists of various steps like generation
of hypothesis, collection of data, and application of
Indian J Pharmacol. 2012 Jul-Aug; 44(4):
O Any science needs precision for its
O Precision is all the more important when it
comes to health sciences. For precision; facts,
observations or measurements have to be
expressed in figures.
O Medicine is essentially an empirical science. It
depends on observations and not on theories or
O As a part of clinical practice or research we
deal with many observations, which when
systematically arranged, are called Data.
O The process of converting data into information
requires a special approach called statistics.
O ‘Statistic’ means a measured or counted fact or
piece of the information, stated as a figure such as
height of one person, birth weight of a baby etc.
Branches of Biostatistics
O Descriptive Biostatistics
Methods of producing quantitative summaries
of information in biological sciences.
Tabulation and Graphical presentation
Branches of Biostatistics…
Methods of making generalizations about a
larger group based on information about a sample of
that group in biological sciences.
Primarily performed in two ways:
O Testing of hypothesis
O Sir Francis Galton
is considered as the
Father of Biostatistics.
O He was the first to apply statistical methods to
the study of human differences and inheritance
of intelligence, and introduced the use of
Questionnaires and Surveys for collecting data
on human communities, which he needed for
genealogical and biographical works and for
his anthropometric studies.
Origin and development of
statistics in medical research
O In 1929,a huge paper on application of
statistics was published in physiology journal
O In 1937, 15 articles on statistical methods by
Austin Bradford Hill, were published in book
O In 1948, a RCT of streptomycin for pulmonary
tb., was published in which Bradford Hill
has a key influence.
O Then the growth of statistics in Medicine from
1952 was a 8-fold increase by 1982.
Sources of medical Uncertainties
O Intrinsic due to biological, environmental and
O Natural variation among methods, observers
and instruments etc.
O Errors in measurement or assessment or errors
O Incomplete knowledge.
Intrinsic variation as a source of
O Biological due to age, gender, heredity, party,
height, weight etc. Also due to variation in
anatomical, physiological and biomechanical
O Environment due to nutrition, smoking, pollution,
facilities of water and sanitation, road traffic,
legislation, stress and strain etc.
O Sampling fluctuations because the entire world
cannot be studied and at least future cases can
never be included.
O Chance variation due to unknown or complex
to comprehend factors.
O Biostatistics is the term used when tools of statistics are
applied to the data that is derived from biological
sciences such as medicine.
O Any science demands precision for its development,
and so does medical science.
O For precision,facts,observations, or measurements have
to be expressed in figures.
O Everything in medicine be it research, diagnosis or
treatment, depends on counting or measurement.
O High or low blood pressure has no meaning, unless it
is expressed in figures.
O Thus medical statistics or biostatistics can be called
O In nature, blood pressure, pulse rate, action of a
drug or any other measurement or counting varies
not only from person to person but also from group
O The extent of this variability in an attribute or a
character, whether it is by chance i.e. biological or
normal, is learnt by studying statistics as a science.
O Variation more than natural limits may be
pathological, i.e., abnormal due to the play of
certain external factors. Hence biostatistics
may also be called a science of variation.
O The data after collection, lying in a haphazard
mass are of no use, unless they are properly sorted,
presented, compared, analyzed and interpreted.
O For such a study of figures, one has to apply
certain mathematical techniques called statistical
It is the science which deals with development and
application of the most appropriate methods for the:
Collection of data.
Presentation of the collected data.
Analysis and interpretation of the results.
Making decisions on the basis of such analysis.
O Statistics arising out of biological sciences, particularly
from the fields of Medicine and Public health.
O The methods used in dealing with statistics in the fields
of medicine, biology and public health for planning,
conducting and analyzing data which arise in
investigations of these branches.
ROLE OF BIOSTATISTICIANS
Identify and develop treatments for disease and estimate
Identify risk factors for diseases.
Design, monitor, analyze, interpret, and report results of
Develop statistical methodologies to address questions
arising from medical/public health data.
Locate , define & measure extent of disease
Ultimate objective improve the health of individual &
APPLICATION OF BIOSTATISTICS
As a Science
As a Science
In Physiology And Anatomy
O To define what is normal or healthy in a
O To find the limits of normality in variables such
as weight and pulse rate etc. in a population.
O To find the difference between means and
proportions of normal at two places or in
O Eg : The mean height of boys in Gujarat is less
than the mean height in Punjab. whether this
difference is due to chance or a natural
variation or because of some other factors
such as better nutrition playing a part, has to
O To find the correlation between two
variables X and Y such as height and
whether weight increases or decreases
proportionately with height and if so by how
much, has to be found.
O To compare the efficacy of a particular drug,
operation or line of treatment – for this, the
percentage cured, relieved or died in the
experiment and control groups, is compared and
difference due to chance or otherwise is found by
applying statistical techniques.
O To find an association between two attributes such
as cancer and smoking or filariasis and social class
–an appropriate test is applied for this purpose.
O To identify signs and symptoms of a disease
O Cough in typhoid is found by chance and fever
is found in almost every case.
O The proportional incidence of one symptom or
another indicates whether it is a characteristic
feature of the disease or not.
O To test usefulness of sera and vaccines in
the field – percentage of attacks or deaths
among the vaccinated subjects is compared
with that among the unvaccinated ones to find
whether the difference observed is statistically
O In epidemiological studies – the role of
causative factors is statistically tested.
O Deficiency of iodine as an important cause of
goiter in a community is confirmed only after
comparing the incidence of goiter cases before
and after giving iodized salt.
O For decades, Biostatistics has played an integral role in
modern medicine in everything from analyzing data to
determining if a treatment will work to developing
O The University of North Carolina's Gillings School of
Global Public Health defines biostatistics as "the
science of obtaining, analyzing and interpreting data
in order to understand and improve human health.”
[source: UNC School of Public Health,USA.]
O Most people have heard the statistic that
Heart disease is the leading cause of death in
O But how do we know this fact to be true?
O Where did that information come from?
* [source: Center for Disease Control, USA]
O Back in 1948, when a lot wasn't known about the
factors leading to heart disease and stroke, a health
research study -- known as the Framingham
Heart Study -- was done on 5,209 people living in
the town of Framingham, Mass.
O These participants hadn't developed any known
symptoms of cardiovascular disease and hadn't had
a stroke or heart attack.
O They agreed to be followed over a period of time to
help researchers learn what factors lead to both
O The study was landmark in several ways. It showed
that there was no one cause for getting a heart attack,
and combining information about several risk factors
could estimate the risk of someone getting the disease.
O Thanks to the Framingham Study, (which is still
going on today), we now know the major risk factors
that lead to cardiovascular disease.
O To reach these conclusions, researchers simply
followed the numbers -- the Biostatistics numbers to
O Documentation of medical history of diseases.
O Planning and conduct of clinical studies.
O Evaluating the merits of different procedures.
O In providing methods for definition of
‘normal’ and ‘abnormal’.
O To provide the magnitude of any health problem in
O To find out the basic factors underlying the ill-
O To evaluate the health programs which was
introduced in the community(success/failure).
O To introduce and promote health legislation.
Role of Biostatistics in Health
Planning and Evaluation
O Statistics arising out of biological sciences,
particularly from the fields of Medicine and
O The methods used in dealing with statistics in
the fields of medicine, biology and public
health for planning, conducting and analyzing
data which arise in investigations of these
O In carrying out a valid and reliable health situation
analysis, including in proper summarization and
interpretation of data.
O In proper evaluation of the achievements and failures of a
O Biotechnology can focus on a whole range of
topics, from genetic modification of plants and
animals to gene therapy, medicine and drug
manufacturing, reproductive therapy, and even
O In all cases, research is carried out by developing
something and testing whether or not it has the
O Determining performance requires statistical
analysis of results.
O To evaluate the efficacy of sera and vaccines in the
O In epidemiological studies-the role of causative
factors is statistically tested.
O To test whether the difference between two
populations is real or a chance occurrence.
O To study the correlation between attributes in the same
O To measure the morbidity and mortality.
O To evaluate achievements of public health programs.
O To fix priorities in public health programs.
O To help promote health legislation and create
administrative standards for oral health.
O It helps in compilation of data, drawing
conclusions and making recommendations.
O For students of medicine/dentistry
O By learning the methods in biostatistics a student
learns to critically evaluate articles published in
medical and dental journals or papers read in
medical and dental conferences.
O To understand the basic methods of observation
in clinical practice and research.
O Statistics and Human Genetics are twin
subjects, having grown with the century
together, and there are many connections
between the two.
O Some fundamental aspects in particular the
concept of Analysis of Variance, first arose in
Human Genetics, while statistical and
probabilistic methods are now central to many
aspects of analysis of questions is human
O The most common areas where one can find
an extensive applications of statistical methods
in human genetics is
* Human Genome Project
* Linkage Analysis
IN Environmental science
Environmental statistics covers
a number of types of study:
O Baseline studies to document the present state of an
environment to provide background in case of unknown
changes in the future.
O Targeted studies to describe the likely impact
of changes being planned or of accidental
O Regular monitoring to attempt to detect
changes in the environment.
O Over the past 2 decades, there have been
revolutionary developments in life science
technologies characterized by high throughput, high
efficiency, and rapid computation.
O Nutritionists now have the advanced methodologies
for the analysis of DNA, RNA, protein, low-
molecular-weight metabolites, as well as access to
O Biostatistics, which can be defined as the process of
making scientific inferences from data that contain
variability, has historically played an integral role in
advancing nutritional sciences.
O Currently, in the era of systems biology statistics has
become an increasingly important tool to
quantitatively analyze information about biological
O Appropriate statistical analyses are expected
to make an important contribution to solving
major nutrition-associated problems in humans
and animals (including obesity, diabetes,
cardiovascular disease, cancer, ageing, and
intrauterine growth retardation).
Application and Uses of
Biostatistics As Figures
O Health and vital statistics are essential tools in
demography, public health, medical practice
and community services.
O Recording of vital events in birth and death
registers and diseases in hospitals is like book
keeping of the community, describing the
incidence or prevalence of diseases, defects or
deaths in a defined population.
O Such events properly recorded form the eyes
and ears of a public health or medical
O What are the leading causes of death?
O What are the important cause of sickness?
O Whether a particular disease is rising or falling
in severity and prevalence? etc.
USES OF STATISTICS IN DENTAL SCIENCE:
O 1. To find the statistical difference between means of
two groups. Ex: Mean plaque scores of two groups.
O 2. To assess the state of oral health in the community
and to determine the availability and utilization of dental
O 3. To indicate the basic factors underlying the state of
oral health by diagnosing the community and find
solutions to such problems.
O 4. To determine success or failure of specific
oral health care programs or to evaluate the
O 5. To promote oral health legislation and in
creating administrative standards for oral
health care delivery.
O Bio-statistical techniques can assure that the results
found in such a study are not merely because of
O In every case of our life, Statistics plays a major role
for better gaining and accurate results.
O A well-designed and properly conducted study is a
basic prerequisite to arrive at valid conclusions.
WA Wallis and HV Roberts, in Nature of Statistics. The
Free Press, New York, 1965
“ He who accepts statistics
indiscriminately, will often be duped
unnecessarily. But he who distrusts
statistics, indiscriminately will often
be ignorant, unnecessarily.”
Biostatistics – A foundation for Analysis in
the Health Sciences: Wayne W. Daniel,
Seventh Edition, Wiley Students Analysis.
A First Course in Statistics with Application:
A.K. P. C Swain, Kalyani Publishers
Methods in Biostatistics sixth edition : BK
Fundamentals of Biostatistics : Sanjeev BS
Rao KV. Biostatistics: A manual of statistical
methods for use in health, nutrition and
anthropology. 2nd ed. New Delhi: Jaypee
Brothers Medical Publisher (P) ltd; 2007.
PREVIOUS YEAR QUESTIONS
Discuss the utilization of biostatistics in Public
health dentistry?(RGUHS 2006, 20 marks)
Discuss the role of biostatistics in oral health
research ?(RGUHS 2011, 10 marks)