Module 4 Flashcards
Descriptive epi definition
The study of the amount and distribution of health states in pops by characteristics of person, place, and time.
Used to identify the existence and extent of health problems in a defined population
Four main purposes of descriptive epidemiology
To evaluate trends in health and disease, in order to make comparisons between groups of ppl, geographic areas or over time
To provide a basis for planning, provision, and evaluation of health services- for resource allocation.
To identify emerging or growing problems
To generate new hypotheses for further analytic study
What questions does descriptive epi answer?
Who?
Where?
When?
What?
What are the three main sources of descriptive epidemiologic information?
Case reports
Case series
Cross-sectional studies
Case report
Consists of one patient
Accounts of a single occurrence of a noteworthy health-related incident
May be first in ID’ing a new dz
Cannot produce population-level stats
Case series
Summarize characteristics of similar patients from major clinical settings
Often grouped consecutively and listing common features
Still not representative of the pop, but can help ID’ing new dzs.
Cross-sectional study
Surveys of the population to estimate the prevalence of a dz or risk factor
Examines the relationship between dzs (or other health-related characteristics) and other factors of interest as they exist in a defined population at one particular time
Can do statistical analysis
Common person characteristics
Age
Sex
Gender
Marital status
Sexual orientation and identity
SES
Race/ethnicity
Nativity
Religion
Health disparities definition
Differences in health outcomes that are closely linked with social, economic, and environmental disadvantage
What is the factor that is most tied to differences in health?
Age
Why does susceptibility to dz increase at higher ages?
Biological clock phenomenon
Cumulative effect of outside stressors or exposures
Latency period
Biological clock phenomenon
Waning of immune system with age
Aging may trigger conditions believed to have a genetic basis
Shortening of telomeres with every cell division
Cumulative effect of outside stressors or expsoures
A cumulative effect of stressors and continuous exposure builds up over time
Example: the cumulative effect of radiation over time may increase the risk of some cancers
Latency period (time to develop chronic dzs)
Higher mortality at older ages may reflect the long latency period between initial exposure and subsequent development of some dzs
The male-female health-survival paradox
Higher mortality rate for males
Higher morbidity rates for females
Why?
Influence of biological differences by sex and/or social differences by gender role may both effect these patterns
Overall marital status patterns
Married ppl (esp men) have lower mortality rates than the non-married
Selective factor theory
Healthier ppl are more likely to marry
Better health also leads to longer lasting marriage
Protective factor theory
Marriage protects ppl against poor health
Marriage leads to better health
Health disparities among bisexual participants
More mental health issues
Transgender health disparities
Depression and suicidality rates higher than cisgender peers
Trends with those of lower SES
Higher rate of low birthweight
Higher rate of cardiovascular dz
Higher prevalence of HTN
Higher prevalence of arthritis
Higher prevalence of type 2 DM
Higher incidence of many types of CA
Lower life expectancy
How is SES measured?
Most commonly in three ways:
-Education
-Occupation
-Income
Can also use:
Assets
Household amenities
Educational gradient in both health behaviors and health status
Differences in health status not fully explained by differences in health behavior
Differences not fully explained by income and occupational choice
different thinking and decision making patterns
A continuous gradient by years of education
True for blacks and whites, men and women
Stronger at younger ages (<50)
Whitehall I and Whitehall II
Two long-term cohort (longitudinal) studies in England
Studies of British Civil servants at different levels
Always show a gradient from the highest to the lowest in mortality, incidence of cardiovascular dz and health behaviors, which cannot be explained away by traditional risk factors
The highest always have the best health and lowest mortality. Those in the middle are in the middle for health outcomes. The lowest have the highest mortality and worse health outcomes.
How higher income affects health outcomes
Higher income is associated with better health
Through variation in material conditions
Through variation in social participation and opportunity to control life circumstances
Social causation hypothesis
Conditions associated with lower social class are more likely to produce illness
Downward drift hypothesis
Unhealthy or less fit persons move to impoverished areas or slide down in social status.
The Hispanic paradox
In spite of relatively low socioeconomic status, similar to African Americans and high morbidity form particular conditions such as diabetes, Hispanic mortality rates appear similar to or even lower than that of non-Hispanic whites
Trends in infant mortality by race/ethnicity
Highest in non-Hispanic blacks
Trends in suicide rates by race/ethnicity
Highest in non-Hispanic whites and Native Americans
Possible reasons for the Hispanic paradox
Questionable data reliability
Salmon bias hypothesis
Healthy migrant hypothesis
Cultural protection
Definition of nativity
Place of origin of the individual
Healthy migrant effect
Observation that healthier, younger persons usually form the majority of migrants
-Often difficult to separate environmental influences in the host country from selective factors operative among those who choose to migrate.
-Migrants usually healthier than the average person in the population from which they came
Acculturation
Modifications that individuals or groups undergo when the come in contact with another country.
How acculturation benefits Latinos helath-wise
Higher rates of insurance coverage and access to healthcare
Higher preventative healthcare use, including screening for breast and cervical cancer
Better self-rated health
How acculturation is detrimental to Latinos health-wise
Higher prevalence of illicit drug use
Higher levels of alcohol consumption among women
Higher levels of cigarette smoking
A less nutritious diet
Higher frequency of premature births and low birthweight infants
Higher rate of teen pregnancy
Common ways of comparing by place
International
Within-country regional
Urban/rural
Localized (spatial clustering)
Trends of dz by place in U.s.
Higher rates of leukemia in Midwest
Higher suicide rates in West
Higher stroke mortality rates in the South
Who has general better health: urban, rural, or suburban?
Suburban
Health problems in urban areas
Higher crime rates
Marginalized populations with high risk behaviors
Psychological stressors
Lack of outdoor areas for exercise and recreation
Lower air quality
Health problems in rural areas
Higher prevalence of smoking
Lower prevalence of exercise
Less nutritious diets
Higher prevalence of obesity
Lower prevalence of seatbelt use
Underserved by PCPs
Longer travel times to access care
Life expectancy trends: urban vs rural
Higher in metropolitan areas (urban + suburban)
Localized place comparisons
Dz patterns are due to unique environmental or social conditions found in particular small areas of interest
Some reasons for place variation in dz
Climate
Latitude
Geology
Ethnic and racial variations
Cultural differences (including laws)
Poverty vs wealth
Gene/environment impact
Pollution levels
Major ways of viewing comparisons by time
Secular time trends
Short term variations
Cyclic fluctuations
Point source epidemics
Temporal clustering
Secular trend
A gradual change in the frequency of a dz or death rate over long time periods.
Short term variation definition
A brief or unexpected increase or decrease in the rates of a health-related state or event
Cyclic fluctuation definition
An expected periodic change in the frequency of a dz or death rate over time
Case clustering
Refers to an unusual aggregation of health events grouped together in space and time
Point source epidemics
The response of a group of ppl circumscribed in place and time to a common source of infection, contamination, or other etiologic factor to which they were exposed almost simultaneously
Texas sharpshooter fallacy
Making the assumption that cases appear in a cluster due to a medical or environmental cause, when, in fact, this occurred by change, because of how the cluster was defined
Age effects
True for an age group of people, in all generations and at all periods of time
Period effects
True for people of all ages and generations at one particular period of time
Cohort effect
True for a particular generation or birth cohort of people, independently of age and period of time
