An introduction

Epidemiology matters: a new introduction to methodological foundations

Chapter 1

Epidemiology Matters – Chapter 1 2

Epidemiology is the science of understanding the

causes and distribution of population health so that we

may intervene to prevent disease and promote health.

Epidemiology Matters – Chapter 1 3

Examples of questions epidemiologists ask

What is the incidence of myocardial infarctions between

2010-2020 among women born in 1950 in the United

States?

What are the causes of myocardial infarctions in this

population?

If we were to change population dietary habits, what

improvement in myocardial infarction incidence could we

affect?

Epidemiology Matters – Chapter 1 4

1. Evolution of epidemiology

2. Our approach to teaching epidemiology

3. Seven steps to conduct an epidemiologic study

4. Farrlandia

5. Summary

Epidemiology Matters – Chapter 1 5

1. Evolution of epidemiology

2. Our approach to teaching epidemiology

3. Seven steps to conduct an epidemiologic study

4. Farrlandia

5. Summary

Epidemiology Matters – Chapter 1 6

Evolution of epidemiology

Epidemiology is a relatively new as a formal scientific

discipline

Practice of conducting epidemiologic studies is not new;

‘counting’ health and disease goes back centuries

Many of design and analytic techniques that we use

today arose in response to health concerns during 19th

and 20th century

Epidemiology Matters – Chapter 1 7

Epidemiology, a beginning

John Graunt – 17th century - pioneered approaches to tabulating

population health and mortality in rates, ratios, and proportions

William Farr – 18th and 19th century - developed more

sophisticated life table approaches to understanding the force

and burden of mortality

John Snow – 19th century - used epidemiologic approaches to

understand London cholera epidemic; developed and applied

basic measures of disease frequency and occurrence

Epidemiology Matters – Chapter 1 8

Epidemiology history, continued

19th century – focus on infectious disease

20th century – high-income countries shifted toward

non-communicable diseases

Mid 20th century – methods formalized (1970s)

Late 20th century – Miettinen, Rothman, and

Greenland - modern epidemiology (1980s)

formalized central disciplinary principles

Epidemiology Matters – Chapter 1 9

Current conceptual movements

1. Ecosocial perspective on population health – suggests policies,

institutions, and characteristics of context contribute to the

shaping of health

2. Life course perspective – determinants of health are distributed

across the life course and even before conception

Therefore, epidemiology understands causes of population health

across levels of influence - from cells to society - and across life

course.

````

Social and Economic Policies

Neighborhoods and Communities

Institutions

Living Conditions

Social Relationships

Individual Risk Factors

Genetic/Constitutional Factors

Environment

Individual/Population Health

Pathophysiologic pathwaysLifec

ours

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Kaplan, G. What’s wrong with social epidemiology, and how can we make it better? Epid Rev 2004; 26: 124-135

An ecosocial framework

A lifecourse approach to health production

Uauy, R. et al. Diet, nutrition, and the life-course approach to cancer prevention. J Nutr 2005; 135: 2934S-2945S

Epidemiology Matters – Chapter 1 12

1. Evolution of epidemiology

2. Our approach to teaching epidemiology

3. Seven steps to conduct an epidemiologic

study

4. Farrlandia

5. Summary

Epidemiology Matters – Chapter 1 13

Our approach to teaching epidemiology

We are interested in an epidemiology of consequence, an epidemiology

that can guide the improvement of the health of population

Therefore, we focus here on teaching underlying concepts that start

from understanding populations, and lead the learner through the key

steps to designing an epidemiologic study

We will mention and adopt the labels that are used in many other

epidemiology textbooks (e.g., confounding) but only after we have

introduced the reader to the underlying concepts

Epidemiology Matters – Chapter 1 14

1. Evolution of epidemiology

2. Our approach to teaching epidemiology

3. Seven steps to conduct an epidemiologic study

4. Farrlandia

5. Summary

Epidemiology Matters – Chapter 1 15

Epidemiology of consequence, seven steps

1. Define the population of interest2. Conceptualize and create measures of exposures and health

indicators3. Take a sample of the population4. Estimate measures of association between exposures and health

indicators of interest5. Rigorously evaluate whether the association observed suggests a

causal association6. Assess the evidence for causes working together7. Assess the extent to which the result matters, is externally valid, to

other populations

Epidemiology Matters – Chapter 1 16

Epidemiology of consequence, seven steps

Descriptive epidemiology Step 1. Define the population of interest

Step 2. Conceptualize and create measures of exposures and health indicators

Step 3. Take a sample of the population

Step 4. Estimate measures of association between exposures and health indicators of interest

Assessing for causal effect Step 5. Rigorously evaluate whether the association observed suggests a causal association

Conceptualizing and testing for interactions Step 6. Assess the evidence for causes working together

Step 7. Assess the extent to which the result matters (is externally valid) to other populations

Epidemiology Matters – Chapter 1 17

1. Evolution of epidemiology

2. Our approach to teaching epidemiology

3. Seven steps to conduct an epidemiologic study

4. Farrlandia

5. Summary

Epidemiology Matters – Chapter 1 18

Farrlandia

Examples often based on hypothetical geographic area, Farrlandia

Inspired by William Farr, pioneering epidemiologist and statistician

Through use of Farrlandia examples, students will focus on applying foundational concepts to populations

Epidemiology Matters – Chapter 1 19

1. Evolution of epidemiology

2. Our approach to teaching epidemiology

3. Seven steps to conduct an epidemiologic study

4. Farrlandia

5. Summary

Epidemiology Matters – Chapter 1 20

Summary

This book aims to provide learners with a systematic

grounding in the theoretical underpinnings of epidemiology

with an awareness of the practical considerations that are

essential for public health professionals

This text establishes a foundation by building on

methodological innovation and teaching of the previous

century, while adopting a novel approach to teaching

epidemiologic foundations

Epidemiology Matters – Chapter 1 21

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