Methods Of Public Health data collection Flashcards
What is a determinant?
Factors that play a significant impact on our health status
What is epidemiology?
The study of the distribution and determinants of health-related states events or events in specific populations, and the application of this study to the control of health problems
What is incidence?
The number of people who develop a specific disease or health-related events during a specific time period
Define prevelance
The total number of individuals in a population who have a disease or health condition at a specific period in time
What is a chronic disease?
A disease that persists for a long time , lasting 1 year or more according to the CDC and require ongoing medical treatment and/or limit daily activities.
What are the 3 Ws of epidemiology?
Who, when and where
Who does epidemiology ask?
Age, sex, race, socioeconomic status, behaviors or occupation
When does epidemiology ask questions?
Annual occurrence, seasonal occurrence and daily or even hourly occurrence
Where does epidemiologist ask questions?
Geographic variation, urban-rural differences and location of worksites or school
Describe the general trend for lung cancer rates in the United stages 1930-1999
From 1930 male lung cancer deaths continue to increase significantly higher than female lung cancer deaths
Both peak/ begin to decrease around 1999
Describe pertussis rates for by 5-year age
0-4 years significantly has the highest reported cases per 100,000 population
Describe the rates for infant mortality rates for 2002, by race and ethnicity of other
- Black, non-Hispanic easily at the highest at 13.9 per 1000 live. Births
- Haiwaiian second with 9.6
- American Indian is third with 8.6
- Puerto Rican is fourth with 8.2
- Total US 7.0
- Cuban second to last with 3.7
- Chinese are last with 3.0
What are significant details related to the trends in fatalities associated with farm tractors
- Seems somewhat normally distributed, increasing from 7 AM to 4-5PM and then decreasing downwards generally
- Easily highest fatality peaks are 11 AM -12PM with 17 deaths and 4-5 PM with 25 deaths
- Unusual dip in deaths at 12 - 1PM with 5 deaths
What ages are affected by farm tractor fatalities?
Farm tractor deaths generally increases alongside age peaking at about 45 deaths at age 60-69 with 50-59 following closely behind
Afterwards, there is a downward trend
What was the cause of Legionnaire’s epidemic ?
In July 1976, the American Legion held a four day conference in Philadelphia
Before the event was over, conventioneers felt ill
An investigation determined a hotel was the source and that the causative agent was airborne
What were the consequences of the Legionnaire epidemic?
By early August, 150 cases of the disease and 20 deaths had been reported.
What were the symptoms,s of the Legionnaires epidemic?
Fever, muscle aches and pneumonia
How did epidemiologist determine the cause of the epidemic ?
They enlisted the help of biochemists who found the bacteria responsible for the epidemic
Describe characteristics of chronic diseases
Most chronic diseases cannot be attributed to a single cause
They tend to develop over a period of time, are often disabling rather than rapidly fatal
How has heart disease affected populations since the 1920s?
Since the 1920s, heart disease has been the leading cause of death in the United States for both men and women
How did World War 2 affect heart disease ?
After World War 2, one in every five men was affected with heart disease before the age of sixty
Describe the first major epidemiological study of a chronic disease
In 1848, an epidemiological study was launched in Framingham, Massachusetts to determine contributing factors of heart disease.
More than 5,000 healthy people were examined . They were examined two years later and repeated for the rest of their lives
What were the revelations of Framingham Heart Study?
The 3 major risk factors of heart disease: high blood pressure, high blood cholesterol and smoking
- Some people maintained their youthful blood pressure and cholesterol values as they got older and these people remained healthier
- Since increased blood pressure and cholesterol increased risk of heart disease, this also meant weight gain and lack of exercise also increased risk
Describe the graph showing relative risk factors of Coronary heart disease
Smoking and diabetes mellitus are the highest
Total cholesterol over 220 and hypertension at second
Then BMI over 27
How has the effect of heart disease by and in 1970?
- By the 1970s death rates from heart disease were failing in the United States
- In 1970 the death rate over the previous ten years decreased by 60% from that in 1960
- In 2002, the death from heart disease was 61% lower than it was in 1950
When and how the link between lung cancer and tobacco smoke ?
In 1950 and 1952, two major epidemiological studies were started that established a link between lung cancer and tobacco smoke
Describe the study which established a link between lung cancer and tobacco smoking
Two British epidemiologists , Richard Doll and A. Bradford Hill, sent out questionnaires to all physicians in the UK, over 40,000 responded
They were asked whether they were smokers, past smokers or non smokers
Smokers and ex-smokers provided information on their age at starting to smoke and amount smoked
What were the findings of Richard Doll A. Bradford Hill on the link between tobacco smoke and lung cancer?
- Death rate of lung cancer was 20x in smokers than nonsmokers
- the death rate of ex-smokers was lower than smokers
- the difference in lung cancer mortality between smokers and nonsmokers were the same whether the doctors lived in rural or urban areas
- Deaths from heart attacks were also significantly higher among heavy smokers aged 35 to 45 than among nonsmokers
How did the number of cigarettes smoked in 1971, as a result of the epidemiological study?
By 1971, the average number of cigarettes smoked per day was less than half what it had been in 1952
When individual sources are data sources, what are suitable methods of data collection?
Questionnaires
Surveys
When the environment is used as a data source, what are the best methods of data collection?
Samples from the environment ( such as collection from rivers for chemicals)
Sensors for environmental changes like air quality ratings
When health care providers are a data sources, what are the best methods of data collection?
Notifications to health department if cases of certain diseases are observed
When Non-health related sources are used as data sources(financial, legal) what are the best methods of data collection?
Sales records
Court records
What are study designs?
A specific plan or protocol for conducting a study
Why are studies conducted?
Studies are conducted in an attempt to discover associations between an exposure or risk factor and a health outcome
What are the types of study designs?
Observational
Experimental
What are the types of experimental study designs?
Quasi-experiments
RCT
What are the types of Observational study designs ?
- Cohort
- Case-control study
- Cross sectional survey
What is a prospective study?
A study that looks forward, into the future, examining future events and follows a concern, condition or disease into the future
What is a retrospective study?
A study that looks back in time to study events that have already occurred
What is a cohort study?
A cohort study/longitudinal study examines multiple effects of an exposure
Data collection is usually prospectively
Describe the methodology of a cohort study
The study begins with disease free individuals
Subjects are defined according to their exposure levels(exposed, not exposed) and followed overtime for their outcomes
Outcomes and risks are compared
Is a cohort study prospective or retrospective?
Prospective
Is a case-control study retrospective or prospective?
Retrospective since researchers review events that happened in the past
What was a case-control study?
Starts with people who has the disease and looks back to determine their exposure
Describe the methodology of a case-control study?
Starts with people who have the disease and looks back to determine their exposure
They are compared with controls (healthy individuals) and their histories are compared
Researchers then look back into subjects histories( usually by viewing records or relying on subject recall) to learn about their exposure status
What is a cross-sectional study?
A study that looks at a single point in time
What does a cross sectional study measure?
PREVELANCE but not incidence
Describe a cross-sectional study
It examines the relationship between exposure and outcome prevelance in a population without regard to changes over time
What can cross-section studies be thought of ?
Providing a snapshot of the frequency of a disease or other health related characteristic in a population at a given point in time
What are cross sectional studies used to assess?
The burden of a disease or health needs of a population
Contrast prevalence and incidence of a disease
Prevalence - how wide spread the disease is
Incidence- the risk of contracting the disease
Why is data sampling done?
It is impractical to study a whole population
-sampling allows researchers to infer information about a population, without having to investigate every individual
What is an important aspect when conducting data sampling?
Important that the indivuals chosen are representative of the whole population
Give the different types of sampling
- Simple random sample
- Systematic sample
- Stratified random sample
- Cluster sample
- Convenience sample
- Snowball sample
Describe a simple random sample
In this case each individual is chosen entirely by chance and each member of the population has an equal chance, or probability of being selected
how can a simple random sample be obtained?
One way of obtaining a random sample is to give each individual in a population a number, and then use a table of random numbers to decide high individuals to include
Describe a systematic sample
Individuals are selected at regular intervals from a list of the whole population
Every 10 th member of the population is selectedfrom a list of all population members
Why are intervals chosen in systematic samples?
The intervals are chosen to endure an adequate sample size
Describe a stratified random sample
Divided into sub-groups or strafaa who all share a similar characteristic (grade level, age, sex, smoking habits)
The study sample is then obtained by taking samples from each stratum
Describe the cluster sample
- Sub-groups of the population are used as the sampling unit, rather than individuals
- population is divided into sub-groups, known as clusters and a selection of these are randomly selected to be included in the study.
All members of the cluster are then included in the study
What is the easiest method of sampling?
Convenience sampling as it is done at the “convenience” of the sample
Describe the convenience sample
Method uses readily available groups or units of individuals, or whichever individuals are easiest to reach
When is snowball sampling often used.
Used when investigating hard to reach groups
Describe snowball sampling method
Existing subjects are asked to nominate further subjects known to them, so the sample increases in size like a rolling snowball
Give an example of the snowball sampling method
For example, when carrying out a survey of risk behaviors amongst intravenous drug users, participants may be asked to nominate other users to be interviewed
List the types of data
- Nominal
- Ordinal
- Interval
- Ratio
What is nominal data?
- Used for labeling variables
- Could be called “ labels”
- No numerical significance
What is ordinal data?
The order of the values is important/significant, but the differences between each one is not really known
Typically measures of non-numeric concepts
What is interval data?
- Interval scales are numeric scales in which we known not only the order, but also the exact differences between the values
- Do not have a “true zero” 0 is a position on the scale
Describe ratio data
- Tells the order and the exact value between units
- Clear definition of zero( 0 means none)
Relook over slides
Especially examples of sample and studies
Describe the graph for MULTIPLE risk factors of coronary heart disease
Highest risk factor combo- smoking+ BMI over 27+ Cholesterol over 220 + DM and hypertension
Second highest is Smoking+BMI+ TC over 220+ DM
Third is Smoking+ BMI+ TC over 220
Lowest combo- smoking+ BMI
Describe the graph showing world trade centers and and survivors correlation to hours after attack
Vastly more rescuers and non rescuers survivors the lower the amount of time after attack(looks like chi square distribution)
Describe the graph showing the seasonal pattern of rubella, influenza and rotavirus
Every there is a peak in occurrence in January
Describe the graph showing the cases of salmonella enteritis in Chicago
Highest in February 14 and 15 but quickly decreases in number of cases by 16 and stays low
