Exam 1 Study Guide (Ch. 3 & 5)

What is the definition of epidemiology?

Epidemiology is the study of the distribution and determinants of health-related states and events in populations, and the application of this study to control health problems

What involves multiple disciplines in sciences?

Studies

What is the term used for “do certain conditions affect more old or young people”?

Distribution

What term is used for the factors that predispose us or protect us from developing certain conditions?

Determinants

What is population?

Related to community, vs. clinical that is related to individuals

What is the equation to measure prevalence?

Number of cases divided by total number in the population at one point in time

How is prevalence reported?

As a percentage or a decimal

What is incidence?

Refers to NEW cases within a population over an observed time period

Is prevalence a proportion or a rate? Do they require units? What should also be reported?

* A proportion; NOT a rate
* No units are needed
* Date of measurement should be reported

What is the incidence rate?

The number of new cases per population at risk per unit time

What is one of the most reported incidence measures?

Mortality rate

What is mortality rate?

The incidence of death in a defined population over a specified time

In terms of epidemiology, what is considered the numerator and denominator?

* Numerator: number of people who die during the period
* Denominator: number of people alive

What is crude mortality?

Total number of deaths divided by total population per unit time

What is age specific mortality?

Number of deaths in certain age group divided by number of people in the age group per unit time

What is case fatality rate?

Number of deaths cause by a specific disease divided by the number of people who have the disease per unit time

Criteria of classification used in ophthalmic epidemiology studies: Cataracts

LOCS (Lens Opacities Classification System)- is a repeatable grading system

Criteria of classification used in ophthalmic epidemiology studies: ARMD

Wisconsin Grading Scale- for type location and size of drusen (0-8)

Criteria of classification used in ophthalmic epidemiology studies: Glaucoma

Definite or probable photographic criteria of glaucomatous ONH

Criteria of classification used in ophthalmic epidemiology studies: Diabetic Retinopathy

ETDRS grading system

Criteria of classification used in ophthalmic epidemiology studies: Mild NPDR

At least 1 MA and definition not met for any other disease severity level

Criteria of classification used in ophthalmic epidemiology studies: Moderate NPDR MA and Hemes

May include soft exudates, venous beading IRMA with definition not met for any other disease severity level

Criteria of classification used in ophthalmic epidemiology studies: Severe NPDR

CWS venous beading and IRMA in at least two of fields 4-7

Criteria of classification used in ophthalmic epidemiology studies: Non High Risk Early PDR

Neovascularization with definition not met for high risk PDR

Criteria of classification used in ophthalmic epidemiology studies: High Risk PDR

New vessel growth on or within I DD of optic disc with or w/o VH or pre retinal hemorrhage, vitreous or preretinal hemorrhage with NVD or NVE

What is the Andhra Pradesh Eye Disease study and what were their major findings?

* Determine the prevalence and risk factors for eye and vision conditions in an Indian population
* Major findings: confirmed smoking as a major risk factor for cataract and macular degeneration

What is the Baltimore Eye study and what were their major findings?

* Estimate prevalence of eye disease in an urban US population of Black and White participants age 40 and older
* Major findings: Confirmed African Americans are at much higher risk for glaucoma

What is the Barbados Eye study and what were their major findings?

* Describe the epidemiology of visual impairment in a large population of people of African ancestry
* Major findings: Confirmed cataract and glaucoma are much higher and macular degeneration much lower in a Black population compared to published large scale studies of other races

What is the Beaver Dam Eye study and what were their findings?

* Estimate incidence, prevalance and associated risk factors of cataract, age related macular degeneration, and diabetic retinopathy in a primarily White rural midwestern US population
* Findings: Incidence of macular degeneration is significantly lower in each succeeding generation
* The following did not increase or decrease risk of any macular degeneration:
* Use of a statin for cholesterol control
* Low to moderate alcohol intake
* The following was not associated with development of early macular degeneration but decreased risk of advanced or exudative macular degeneration:
* Moderate exercise

What is the Blue Mountain Eye study and what were their major findings?

* Determine the epidemiology of eye conditions in a stable homogenous population in urban/suburban Australian population
* Major findings: Prevalence and incidence of cataract, glaucoma, and macular degeneration similar to other population studies of primarily White populations (Beaver Dam, Rotterdam, Framingham)

What is the Chesapeake Bay study and what were their major findings?

* To quantify ultraviolet radiation exposure in Chesapeake watermen workers as relates to cataract and macular degeneration
* Major findings: UV exposure was associated with cortical cataract but not nuclear cataract nor macular degeneration. “A doubling in lifetime UV-B exposure led to a 60% increase in the risk of cortical cataract.”

What is the Chinese American Eye study and what were their major findings?

* Determine prevalence of eye conditions in Americans of Chinese ancestry and compare to published studies of Americans of Latino ethnicity, African ancestry, and White populations
* Major findings: Prevalence of glaucoma, cataract, and diabetic retinopathy are similar to White and Latino populations. Prevalence of macular degeneration was lower than Whites but as low in Blacks

What is the Los Angeles Latino Eye study and what were their findings?

* Describe visual impairment burden, incidence of visual impairment and blindness, and risk factors for specific conditions in an American Latino population. Early macular degeneration was similar in prevalence and incidence to White populations. Advanced macular degeneration was lower for ages 40 to 69 but similar over age 70. Annual incidence of cataract was significantly lower than in Black population studies. In contrast to Rotterdam and Baltimore, type 2 diabetes slightly increased risk of open-angle glaucoma by 1.4 times

What was Rotterdam study’s initial purpose and what were their major findings?

* Initial purpose: Large population cohort study on chronic ophthalmic, cardiovascular, neurologic, and locomotor conditions in the Netherlands
* Major findings: Overall prevalence of blindness and visual impairment in age 55 to 64 was 0.1% each but affected 3.9% and up to 11.8% of persons age 85 and older respectively. Confirmed that smoking significantly increases risk of macular degeneration

What was Shahroud Eye cohort study (Iran) original purpose and what were their findings?

* Describe the epidemiology by age of macular degeneration, glaucoma, and visual impairment in a Middle Eastern population. Prevalence of macular degeneration in this Middle Eastern population was higher than those reported for East Asian and African studies but lower than European and U.S. studies. Prevalence of glaucoma was similar to White, Asian, and Hispanic populations

What is the Tehran Eye study and what were their major and secondary findings?

* Quantify the frequency of visual impairment and associated conditions in Tehran using a calculated sample size sufficient to detect at least a 2% prevalence
* Major findings: Prevalence of visual impairment, low vision, blindness, and diagnosed causes reported. Uncorrected refractive error and cataract were by far the most common causes
* Secondary findings: Nuclear sclerotic cataract higher than grade 3 was associated with myopia, but cortical cataract above grade 3 was associated with hyperopia

Hypertension, Health outcome is stroke. What cause is this?

Component cause

Treponma pallidum, Health outcome is syphilis. What cause is this?

Necessary cause

Type A personality, Health outcome is heart disease. What cause is this?

Component cause

Skin contact with a strong acid, Health outcome is burn. What cause is this?

Sufficient cause