Lecture 4 Notes: Epidemiology
Epidemiology, what we know: how things are spread, dealt with, controlled, and researched. The study of disease, and how it affects health. Attempt to eradicate and control. Things such as vaccines to control health problems, sanitation, quarantine, research facilities, healthcare centers. Water filtration. Health codes. Try to contain/control risk factors for bad health outcomes. Finding patterns in disease and spread of health issues.
Epidemiology: the study of the distribution and determinants of health related states or events in specified populations, and the application of this study to control health problems, “population medicine”
Cornerstone of Public Health
• objectively examine factors, variables, statistics – “evidence-based” • utilize data for prevention efforts
• try to explain why some things happen to some people & not others • shift from traditional epi to wider uses
• we must target multiple causal factors & collaborate with multiple disciplines
• Endemic – the constant presence of disease or infectious agent within a geographic area If you want to learn more check out How is kinship culturally constructed?
• Epidemic – the occurrence of a disease in excess of normal expectancy
• Pandemic – an outbreak of a disease over a wide geographical area, such as a continent
We measure health through: death (mortality), illness (morbidity), injury/disability, productive life years lost, lost opportunity (all negative), quality of life, healthy days of life, psycho-social measures (positive measures)
Don't forget about the age old question of State the seven sins of memory.
• track diseases, conditions
• monitor health & quality of life
• identify opportunities for prevention & protection Don't forget about the age old question of What is porter's competitive advantage?
• create “surveillance systems” & large national data bases
• Distribution of resources (?)
The Problem: The What, Who, Where (PERI)
• What is the burden of disease in terms of mortality, morbidity and has it changed over “Time”?
• “Person & Place” – description & distribution (“spread”)
• Look for patterns & associations in the occurrence of Dz/condition so we can …
• Come-up with hypotheses, ideas about cause(s)
Measuring Health & Disease:
• Usually expressed using health statistics based on the traditional medical model of describing ill health
• Rate – a measure of some event, disease, or condition in relation to a unit of population, along with some specification of time Don't forget about the age old question of In what year did new york evening post the first newspaper to cover boxing?
Formula for a Rate:
Number of events, cases, or deaths**
Population in the same area**
(** in a specified time period)
To calculate a rate, you must have accurate counts for:
3. a defined population
4. a specified period of time
Commonly Used Rates
• Death rates – also known as mortality or fatality rates, often expressed as the # of deaths per 100,000
• Adjusted rate – a rate that is for a total population but is statistically adjusted for a certain characteristic such as age (“age adjusted rate”)
• Specific rate – rate for a particular population subgroup such as for a specific disease (disease-specific) or for a particular age of people (age-specific) ex. “African American colon cancer rate”
• Crude rates – those in which the dominator includes the total population
• Incidence rate– the number of new health-related events or cases of a disease in a population exposed to that risk in a given time period If you want to learn more check out What are the different functional parts of the nervous system?
• Prevalence rate– calculated by dividing all current (existing) cases of a disease (old & new) by the total population
• Attack rate– a special incidence rate calculated for a particular population for a single disease outbreak expressed as a percentage
Etiology: what are the contributory causes, has an association been established at the individual level? Does the cause precede the effect? Has the cause been shown to alter the effect?
Risk indicators/markers: types of factors/conditions that groups of people with the disease or condition have that people without don’t
• “things” whose presence are associated with increased chance that Dz/condition will develop later If you want to learn more check out What is the admission revenue if you have a depreciation exp of 10,500?
• can be environmental, social & behavioral influences – not just individual behavior
• can be modifiable (susceptible to change) or non-modifiable (immutable to change)
• More likely to be under control of an individual (doesn’t mean it is easy to change!)
• Not all persons with the risk factor will get the disease or condition, but vice versa, because the risk factor is absent doesn’t mean you won’t get the disease
Socio-Ecological Influences on Health
• Ecological perspective: Multiple factors and pathways
• Risk factors: Increase likelihood of condition or disease
• Social and cultural determinants: Social status and standing • Global health influences: Population, pollution, poverty and more 4 types of health influences risk conditions and factors:
∙ Access to health care services
∙ Behavior: have the biggest impact on health, what we do or don’t do impacts us
1. Cause is linked to effect (outcome)
2. Cause comes before the effect (“temporal sequence”)
3. Changing the causes, changes the effect (a “relationship”) Relationships between cause and outcome
∙ Studies produce same results over time between different populations, that explain a relationship
Recommendations For reducing and eliminating the H problem: • What works to reduce the health impacts?
• What is the quality of the evidence for the intervention? • What is the impact of the intervention in terms of benefits and harms? • What do we know based on past experience?
What steps do we take to implement?
• How can we get the job done?
• When should the implementation occur?
• At whom should the implementation be directed?
• How should the intervention(s) be implemented?
Healthy People 2010: Objectives for the Nation
Goal 1: Increase Quality and Years of Healthy Life: The first goal of Healthy People 2010 is to help individuals of all ages increase life expectancy and improve their quality of life.
Goal 2: Eliminate Health Disparities” The second goal of Healthy People 2010 is to eliminate health disparities among different segments of the population.
Healthy People 2020 Objectives for the Nation:
• Attain high-quality, longer lives free of preventable disease, disability, injury, and premature death.
• Achieve health equity, eliminate disparities, and improve the health of all groups.
• Create social and physical environments that promote good health for all.
• Promote quality of life, healthy development, and healthy behaviors across all life stages.
*We must collect data to discover issues, causes, effects, and what to do next: causes of mortality, life expectancy, increasing health disparities
What kills us now?
1. Heart disease: 614,348
2. Cancer: 591,699
3. Chronic lower respiratory diseases: 147,101
4. Accidents (unintentional injuries): 136,053
5. Stroke (cerebrovascular diseases): 133,103
6. Alzheimer's disease: 93,541
7. Diabetes: 76,488
8. Influenza and pneumonia: 55,227
9. Nephritis, nephrosis: 48,146
10. Intentional self-harm (suicide): 42,773
Acute – signs & symptoms of short duration; usually severe & impair normal functioning
Chronic – persists over time (> 3 mo.) Most of our chronic health problems, conditions are PREVENTABLE !
Health disparities: increasing by/in:
• Ethnic and racial groups
• Age groups
• Educational Attainment