Epidemiology: Principles and Applications

• Epidemiology studies disease spread, causes, and effects on populations.
• It involves understanding patterns, causes, and effects of health and disease.
• Epidemiologists track disease outbreaks, identify risk factors, and develop control strategies.
• Epidemiology is essential in public health, guiding health policies and practices for population health.
• Statistics and epidemiology are closely linked.

Hippocrates: The Father of Medical Research (400 BC)

• Hippocrates sought the logic of illness through environmental influences and disease occurrence.
• He introduced the terms "epidemic" and "epidemiology."
• He determined diseases occurred in specific places at specific times, such as epilepsy and cancer.
• He first introduced the concept of 'risk factors', suggesting each disease is caused by different risk factors.
• He wrote 3 articles on epidemiology: Epidemic I, Epidemic II and On Airs, Waters and Places.

John Snow: The Father of Modern Epidemiology

• John Snow (1813-1858) was a British Physician.
• A major cholera outbreak occurred in London in 1849, resulting in approximately 15000 deaths.
• Snow proposed people were infected by swallowing "something" multiplying in the intestines.
• Observation and investigation showed cholera cases were more common in areas supplied from polluted Thames riverbanks.
• Snow conducted an experiment by sealing a water pump in a highly infected neighborhood to prove his theory.
• Cholera disappeared from the neighborhood as a result.

Florence Nightingale: The Founder of Modern Nursing

• Florence Nightingale (1820-1910) was a British nurse and statistician.
• She was a nurse in the Crimean War (1853-1856) and discovered most deaths were due to preventable diseases from poor hygiene.
• Nightingale presented data in the Nightingale Rose Chart, improving sanitary conditions and reducing death rates.
• She established the Nightingale Training School of nursing in 1860 at St. Thomas Hospital in London.
• Nightingale advocated for sanitary reform and better hygiene practices, improving public health.
• Nightingale was an early pioneer of data visualization in healthcare.

Edward Jenner and Smallpox: The First Vaccine

• In 1796, British physician Edward Jenner addressed a smallpox outbreak.
• Jenner observed milkmaids with cowpox were protected from smallpox.
• Jenner hypothesized cowpox exposure could protect against smallpox.
• He tested his hypothesis by inoculating a 9-year-old with material from a cowpox sore.
• Months later, he exposed the child to variola virus multiple times, but the child never developed smallpox.

James Lind and Scurvy: First Intentional Clinical Trial

• James Lind (1716-1794) was a British military surgeon in the Scottish and Royal navies.
• British sailors suffered from a devastating disease during long trips, but the etiology was unknown.
• Lind observed sailors consumed a poor diet lacking fresh fruits on board.
• Lind hypothesized limes would help sailors with the disease.
• Lind selected 12 sailors, gave 6 their usual diet, and 6 received 2 oranges and 1 lime daily for 6 days.
• Two sailors among the latter group had complete symptom withdrawal.
• Lind conducted the first clinical trial in 1747 and proved scurvy was caused by a lack of citrus fruits.

The British Doctors Study: The First Large Prospective Study

• The study began in 1951, led by Sir Richard Doll and Sir Austin Bradford Hill.
• The study involved 34,000 male British doctors from across the UK.
• The doctors were asked about their smoking and followed over time.
• Study sought to correlate smoking with diseases like lung cancer and cardiovascular issues.
• The British Doctors Study was the first large prospective study that established links between smoking and lung cancer (1954).
• It established links between tobacco smoking and myocardial infarction and chronic obstructive pulmonary disease (1956).

Thomas Bayes: Father of Bayesian Probability

• Thomas Bayes (1702–1761) was an English statistician, philosopher, and theologian.
• He is best known for developing Bayes' Theorem.
• Bayes’ Theorem has become a cornerstone of modern probability theory and statistics.
• It is central to machine learning, epidemiology and data analysis
• Bayes' Theorem revises the probability of an event based on new evidence.
• It helps adjust understanding based on incoming data.
• Alan Turing solved the Enigma code in WW2 using Bayes' theorem.

Modern Use of Statistics in Medicine

• Modern medicine uses statistical models, such as risk scores, to predict patient outcomes.
• Artificial intelligence and machine learning algorithms are trained on large datasets.
• This provides diagnostic tools for image recognition in radiology and decision support systems
• Cost-effectiveness analyses and statistical models are used to assess the economic impact of treatments.
• They help inform healthcare providers and policymakers in resource allocation.

The Scientific Method

• The scientific method constructs a reliable, consistent, and non-biased representation of world phenomena.
• It is comprised of 5 steps:
• Observation (or literature review)
• Devise a testable research question
• Formulate a specific research hypothesis
• Test the hypothesis with an experiment (or other analysis)
• Derive a conclusion (i.e. accept or reject your hypothesis)

Types of Biomedical Research

• In vitro studies are lab-based research.
• Animal models include studies, usually using rodents.
• Small-scale experimental studies are on humans.
• Large-scale observational epidemiological studies are in humans.
• These studies are cross-sectional, case-control, and/or cohort studies.
• Large-scale interventional studies are clinical trials, and performed on humans.
• Meta analyses and umbrella reviews.

Main Purposes of Biomedical Research

• Evidence-based medicine (EBM) systematically reviews and uses best evidence from clinical research to aid patient care.
• Disease prevention identifies risk and protective factors, enabling public health programmes at preventing disease.