Descriptive Epidemiology Flashcards
Descriptive studies
I. Used to identify a health problem
II. Characterized the amount and distribution of disease.
Analytic studies
- Follows descriptive studies
- Used to identify the cause of the health problem for example hypothesis testing.
Objective of Descriptive Epidemiology
- To evaluate and compare trends in health and disease.
- To provide a basis for planning, provision, and evaluation of health services.
- To identify problems for analytic studies for example generate hypothesis
The three characteristics of epidemiology
person, place, and time
trends of childhood
developmental problems, e.g., congenital birth defects, infectious diseases such as ear infections, measles
trends of teenage years
unplanned pregnancy, substance abuse
trends of adults
accidental injury, homicide, suicide, HIV
trends of older adults
heart disease, cancer
reasons for age associatons/trends
- validity of diagnosis
- Multimodality
- Latency effects
- Biologic clock and behavioral phenomena
validity of diagnosis
Age specific incidence and mortality rate among elderly are often inaccurate.
- multiple sources of morbidity may afflict a single elderly individual.
- classification errors
Multimodality
there can be a linear distribution, and bimodal distribution.
latency effects
There are two different definitions for latency period:
- It’s between the onset of exposure and the appearance of clinical symptoms.
- Between start of the disease process.
(pathogenesis) .
Biologic clock and behavioral phenomena
Waning of the immune system
– increased susceptibility to disease
• Aging
– appearance of conditions believed to
have genetic basis
– Huntington’s disease
• Behavioral Phenomena
- speeding is more common amongst young adults than older ones.
sex differences
All cause age specific mortality rates higher for men than women
- social factors
-may have biological basis
Female paradox
- Female age standardized morbidity rates for many conditions are higher than male rates
-Higher rates for pain, asthma, lung difficulties, depression
Reasons for patterns of chronic heart disease (CHD) difference among women
Important biologic parameters as the basis for the observed differences:
- differences in hormonal profiles such as estrogen production.
- Lower incidence before menopause
In general married people are found to be ___ and have lower _____ and _____
healthier; morbidity and mortality
What is protective factor of marital status
an environment conducive to health, e.g. psychological and social support.
What is selective factor of marital status
People who marry may be healthier to begin with
Race is a ____ and ____ construct
social and culture
What is observed in mortality and morbidity graphs according to race and ethnicity
If you look at third and fourth highest diseases for each race, there’s a variation observed. Just like we do with any other descriptive analysis, we ask why we observe these differences?
Why is there a lower rate of CHD among Mexican Americans?
- Dietary preferences
- Social support mechanisms
What did the San Antonio Heart study show?
Found higher rates of diabetes among Mexican Americans.
What makes the Hispanic population in the U.S different from usual trends that are observed in Epidemiology?
Usually there’s an inverse association between socioeconomic status and mortality, but this is not observed in Hispanic Americans. They have a low SES, but have lower mortality rate.
A good number of the older generations go back to their home country and there is no record of their death. This creates a “Salmon Bias Effect” - they are statistically immortal.
What demographic of people usually migrate to the United States?
Healthier, younger persons usually form the majority of migrants
-Explanation for Hispanic Mortality Paradox.
Acculturation hypothesis
Immigrants’ health profile converge with that of native born
-Migrant studies
How is low social class related to excess mortality, morbidity, and disability rates?
-poor housing, crowded conditions, poor education, low income, and incidence of severe mental illness.
What are the types of place comparisons?
Geographic variations, urban/rural differences, and localized occurrence of disease.
World Health Organization(WHO)
tracks international variations in rates of disease through the country to observe international comparisons of disease frequency.
- variations are attributable to climate, culture, dietary habits, population density, poverty level and health care access.
Within country variations in rates of disease may be due to ..
variations in climate, geology, latitude, pollution, and ethnic and racial concentrations.
In U.S, comparisons can be made by region, state, and or county.
Urban diseases and mortality are associated with …?
Crowding, pollution, and poverty
What increases with decreasing urbanization?
Mortality, CVD mortality, poor health status, inadequate access to health care
Localized place comparisons
Disease patterns are due to unique environmental or social conditions found in particular area of interest.
Example is fluorosis
Reasons for place variation in disease
- gene/environment interaction
- Environmental factors such as chemical agents linked to cancer and infectious disease vector
- Influence of climate such as melanoma whcih is related to latitude, and hansen’s disease
