Epidemiologists- are scientist devoted to the study of health *determinants,* the *distribution* of disease in communities, and the *validity of disease risk factors.*
Ex. John Snow
– *The methods to estimates characteristics of a population on the basis of a sample.*
– Characteristic of the population at all levels (person,place, and time) must be operationalized so that they can be assessed with quantitative (statistical methods.
– Utilizes measures of correlation (covariation) of strength of relationshiop and various statistics (F,t, chi- schi-square) for determining the likelihood that something occurred by chance.
It has the explicit purpose of understanding and influencing healthful *behavioral patterns*, as part of population wide initiatives to prevent diseases and promote health.
Ex. smoking ,diet, exersice.
Early adversity—–> bad health behavior choices—–> bad outcomes
There was 99% of what we would know does not have to do with early adversity.
— This was not a very strong prediction of this.
+They had a good sample size.
+Good data, over a 20 year period.
Incidence rate per 1,000=
New cases per unit of time/ Persons exposed or at risk per unit of time *1,000
Cases at specific time point/ Persons at exposed or at risk at specific time point * 1,000
2. Panel Studies
This studies have the stricter requirements that the same individuals in the original sample are followed at each repeated assessment.
Ex. Inferences on drug use in college.
They same sample from Freshman, Jrs, Seniors.
A selected group with a targeted diseases is compared to those w/out the disease.
-Its difficult to determining the effects of an intervention is that they intervection may occur at a crisis times.
– Hard to implement at epidemiological scale.
Ex. Chinese Stroke Prevention Trail
2. Alameda County population Study
3. China Stroke Prevention Trial.
A major finding of the study was that some of the best predictors of health disease and early death are direct consequences of own behaviors.
– Smoking, obesity, high cholesterol levels, physical inactivity, and possible excessive tention and stress.
It also broke new going by demostraiting the relationship between social support and health outcomes.
Those who are more “socially connected”, had significantly greater chances of survival than those who are less connected.
It each urban are, one community was choosen as the intervention site and the other as the control site.
They received health education and health promotions services to help participants to avoid cigars and control blood pressure.
— Time Course
–Rate (of change)
-* time course* will affect decision about study design and interpretation of findings.
*Rate of change * will inform the relatively stability or growth in a disease or behavior.
—AIDS epidemic in 1980’s
However, Sunlight is also an important source of vitammin D, and some cancers may be related to deficiencies in this important vitamin