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80 Cards in this Set
- Front
- Back
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AIDS
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AIDS is diagnosed when your CD4 cell count goes below 200. Even if your CD4 cell count is over 200, AIDS can be diagnosed if you have HIV and certain diseases such as tuberculosis or Pneumocystis carinii pneumonia (PCP)
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HIV
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Infection. The earliest stage is right after you are infected. HIV can infect cells and copy itself before your immune system has started to respond. You may have felt flu-like symptoms during this time.
Response. The next stage is when your body responds to the virus. Even if you don’t feel any different, your body is trying to fight the virus by making antibodies against it. This is called seroconversion, when you go from being HIV negative to HIV positive. No symptoms. You may enter a stage in which you have no symptoms. This is called asymptomatic infection. You still have HIV and it may be causing damage that you can’t feel. Symptoms. Symptomatic HIV infection is when you develop symptoms, such as certain infections, including PCP. |
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Normal CD4 Counts
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Usually, CD4 cell counts in someone with a healthy immune system range from 500 to 1,800 per cubic millimeter of blood.
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Male HIV/AIDS tramsmission in 2006
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67% MSM contact
16% IDU 12% Both |
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Female HIV/AIDS transmission in 2006
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80% High Risk Sexual contact
19% Other/not identified |
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Proportion of HIV/AIDS among Adolescents and Adults 2006
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49% Non-Hispanic Black
31% Non Hispanic White 18% Hispanic 1% Asian <1% American Indian/Alaska Native |
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Proportional distribution of HIV/AIDS cases among adults and adolescents diagnosed from 2003 through 2006
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Proportion of HIV/AIDS cases attributed to male-to-male sexual contact increased from 45% in 2003 to 50% in 2006. HIV/AIDS cases attributed to injection drug use, high-risk heterosexual contact, and male-to-male sexual contact and injection drug use remained stable from 2003 through 2006
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Distribution of transmission categories for HIV/AIDS cases diagnosed in 2006
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50% cases diagnosed in 2006 among attributed to male-to-male sexual contact.
3% of HIV/AIDS diagnoses were attributed to male-to-male sexual contact and injection drug use. 13% Injection drug use 33% high-risk heterosexual contact |
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HIV transmission via Male to Male Sexual Contact by race in 2006
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Non-Hispanic whites (41%) Non-Hispanic blacks (38%) Hispanics (19%)
Asians/Pacific Islanders and American Indians/Alaska Natives each accounted for 1% |
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HIV/AIDS cases diagnosed attributed to high-risk heterosexual contact in 2006 by Race
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Non-Hispanic blacks (66%) Non-Hispanic whites (16%) Hispanics (17%). Asians/Pacific Islanders accounted for 1% of cases and American Indians/Alaska Natives accounted for less than 1% of all cases.
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HIV/AIDS Rates for Males by Race in 2006
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the rate (HIV/AIDS cases per 100,000) for non-Hispanic blacks (119.1) was 7 times higher than for non-Hispanic whites (16.7) and more than twice as high as the rate for Hispanics (50.9)
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HIV/AIDS Rates for Females by Race in 2006
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For female adults and adolescents, the rate (HIV/AIDS cases per 100,000) for non-Hispanic blacks (56.2) was nearly 20 times higher than that for non-Hispanic whites (2.9).
The estimated number of HIV/AIDS cases diagnosed in 2006 was similar for Hispanics and non-Hispanic whites, but the rate for Hispanics (15.1) was more than 5 times higher than the rate for non-Hispanic whites. |
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Living with HIV infection (Adults and adolescents-not AIDS) in 2006
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Areas with the highest prevalence rates in 2006 were New York, the U.S. Virgin Islands, Florida, New Jersey, and Louisiana.
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Living with HIV infection (<13 y/o)(not AIDS) in 2006
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Areas with the highest prevalence rates in 2006 were New York, Louisiana, New Jersey, and the U.S. Virgin Islands
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Cumulative through December 2006, a total of 287,954 persons with HIV infection (not AIDS) had been reported from the 45 states and 5 U.S. dependent areas
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65% of these persons were aged 25-44 years at the time of diagnosis.
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In 2006, a total of 566 cases of HIV infection (not AIDS) in children younger than 13 years of age were reported from 45 states and 5 U.S. dependent areas
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Most (80%) of these cases were perinatally acquired. Illinois, California, and New York reported the largest number of cases.
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The diagnosis rate of HIV/AIDS among adults and adolescents was 22.4 per 100,000 population in 2006
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The rate for adults and adolescents diagnosed with HIV/AIDS ranged from 2.3 per 100,000 in Wyoming to 42.6 per 100,000 in Florida.
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Descriptive epidemiology
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Initial investigation of outbreaks of disease frequently starts out with descriptive epidemiology
* Disease incidence * Calculation of rates * ID population at higher risk |
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Agent Factors
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Biological
Bacteria Genetic Chemical Poison ETOH Physical Radiation Fire Nutritional lack, excess |
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Host Factors
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Age
Sex Race/Ethnicity Religion Customs Occupation Heredity Marital Status Family Background Previous Diseases |
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Vertical Transmission
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One generation to the next
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Horizontal Transmission
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Direct (person to person, such as STI's)
Indirect through a common vehicle such as contaminated water. Can be Single, multiple or periodic/continous exposure Vector: such as a mosquito |
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James Lind
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First well-known recorded experiment for scurvy in 1747
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John Gaunt
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London haberdasher who first published mortality data
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Steps to field investigation
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Steps used by CDC disease investigation specialists when they are called to conduct an Epidemic Aid:
Determines the existence of an epidemic Confirm the diagnosis Determine the number of cases Describe the epidemic in terms of person, place and time Determine who is at risk of becoming ill Develop and test hypotheses regarding the causal exposure Compare the hypotheses to the established facts Plan a more systematic study Prepare a written report |
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Basic Question in Epidemiological and Research
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Are exposure and disease linked?
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Exposure (independent variable)
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Risk factor, agent or treatment
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Disease (Dependent variable)
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Disease/Health state or outcome
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Observational Studies
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Cohort: follow people over time to measure exposure and development of disease
Case Control: identify cases of disease and match them with non-cases and ask about exposure Cross sectional: ask population about both exposure and disease at the same time |
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In 2006, a total of 566 cases of HIV infection (not AIDS) in children younger than 13 years of age were reported from 45 states and 5 U.S. dependent areas
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Most (80%) of these cases were perinatally acquired. Illinois, California, and New York reported the largest number of cases.
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The diagnosis rate of HIV/AIDS among adults and adolescents was 22.4 per 100,000 population in 2006
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The rate for adults and adolescents diagnosed with HIV/AIDS ranged from 2.3 per 100,000 in Wyoming to 42.6 per 100,000 in Florida.
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Descriptive epidemiology
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Initial investigation of outbreaks of disease frequently starts out with descriptive epidemiology
* Disease incidence * Calculation of rates * ID population at higher risk |
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Agent Factors
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Biological
Bacteria Genetic Chemical Poison ETOH Physical Radiation Fire Nutritional lack, excess |
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Host Factors
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Age
Sex Race/Ethnicity Religion Customs Occupation Heredity Marital Status Family Background Previous Diseases |
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Vertical Transmission
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One generation to the next
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Horizontal Transmission
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Direct (person to person, such as STI's)
Indirect through a common vehicle such as contaminated water. Can be Single, multiple or periodic/continous exposure Vector: such as a mosquito |
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James Lind
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First well-known recorded experiment for scurvy in 1747
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John Gaunt
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London haberdasher who first published mortality data
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William Farr
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Built upon Gaunt's work by systematically collecting and analyzing Britain's mortality stats and is considered the father of modern vital statistics
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Steps to field investigation
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Steps used by CDC disease investigation specialists when they are called to conduct an Epidemic Aid:
Determines the existence of an epidemic Confirm the diagnosis Determine the number of cases Describe the epidemic in terms of person, place and time Determine who is at risk of becoming ill Develop and test hypotheses regarding the causal exposure Compare the hypotheses to the established facts Plan a more systematic study Prepare a written report |
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Basic Question in Epidemiological and Research
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Are exposure and disease linked?
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Disease (Dependent variable)
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Disease/Health state or outcome
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Observational Studies
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Cohort: follow people over time to measure exposure and development of disease
Case Control: identify cases of disease and match them with non-cases and ask about exposure Cross sectional: ask population about both exposure and disease at the same time |
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Observational Cohort:
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follow people over time to measure E & development of D
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Observational Cross sectional:
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ask population about both E & D at the same time
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Observational Case Control:
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identify cases of D and match them with non-cases and ask about E
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Experimental
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Randomized Control Trial: sample is assigned to E and follow for development of the disease
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Observational Study
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Epidemiologic study of disease and exposure in free-living populations without intervention
According to Last: “nature is allowed to take its course” |
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Case Report
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Detailed, objective report of a single clinical patient, usually with novel disease symptomatology and exposure history
Lacking comparison groups, a case report is not a true study design Performed in the present 1st clue in th eID of a new disease or occurrence Example: OC use increases risk of venous thromboembolism |
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Case Series
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Collections of individual case reports which may occur within a fairly short period of time.
No persons without disease or without exposure are included in the study Lacking comparison groups, a case series is not a true study design Benefit is that this can mean the difference between formulating a useful hypothesis and merely documenting a interesting medical oddity |
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Gottleib and Weisman Case Series Report from 1981
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5 cases of homosexual men with Pneumocystis carinii in severely immunosupressed patientd (HIV)
SF, Miami, NYC |
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Cross-sectional study
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A study conducted in the present, at a single point in time, where each person in the study population or representative sample is assessed for disease status (diseased, well) and exposure (exposed, nonexposed)
Tool for descriptive epidemiology: “snapshot” of the health of a population Can be used to document prevalence: smoking, DM, HTN Limitations: not possible to determine whether the exposure preceded or resulted from the disease (chicken or the egg dilemna) - Both disease and exposure are assessed in the present often conducted as surveys of the population Major Distinction: ask population about both E and D at the same time |
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Case-control Study
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A study that originates in the present with the identification of persons with disease (cases) and purposeful selection of subjects depending if they have (cases) or don’t have (control) a disease – Lyme disease.
Cases and controls are then questioned about history of past exposure. Analyses explore for the possible relationship between past exposure and current disease Retrospective study Major Distinction: ID cases of D and match them with non-cases and ask them about E in the past |
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Observational: Cohort study
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A study in which group of well persons are selected for study – classified by exposure (exposed, nonexposed) and followed forward in time to calculate and compare the incidence rates of new disease in exposed and nonexposed subjects
Incidence study Longitudinal study Prospective study Examples: Framingham, the Nurses Health Study Major Distinction: Follow people over time to measure E & development of D |
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Case control study (Compared to Cohort)
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Small number of subjects
Lower cost One disease: multiple exposures Low prevalence or high prevalence diseases No true estimate of incidence No true estimate of relative risk |
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Cohort (Compared to Case control study)
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Large number of subjects
Higher cost Long time period One exposure: multiple disease outcomes High incidence diseases True estimate of incidence True estimate of relative risk |
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Case control study (Compared to Cohort)
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Odds ratio: exposure odds in cases vs control
Control group susceptible to bias in selection Cases minimally susceptible to selection bias Recall bias Minimal attrition |
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Cohort (Compared to Case control study)
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Odds ratio: disease odds in exposed vs nonexposed
Control group less susceptible to bias Selection bias is important. No recall bias Attrition problems |
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Experimental Studies: Randomized Control Trial (RCT)
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Major Distinction: Sample is assigned to E and follow for development of disease
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Health
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“A state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.”
(Preamble to constitution of the World Health Organization [WHO]) |
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Disease prevention
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Application of medical and public health to prevent disease onset or to facilitate early diagnosis coupled with curative or preventive therapy.
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Health Promotion
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Application of techniques to facilitate physical health, psychosocial well-being and quality of life; and to increase healthy years of life.
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Prevention Example for Cervical Cancer
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Primary
Reduce HPV infection Secondary Pap Smear Tertiary treat for cure surgery chemotherapy |
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Primary Prevention
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Promotion of health at both individual and community levels by facilitating health-enhancing behaviors, preventing the onset of risk behaviors and diminishing exposure to environmental hazards
Primary prevention efforts diminish disease incidence Example: sanitation and sewer system, Prenatal care, immunization programs |
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Secondary Prevention
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Screening for risk factors and early detection of asymptomatic or mild disease permitting timely and effective intervention and curative treatment
Secondary prevention efforts diminish disease prevalence “3 Earlies” – Early detection Early diagnosis Early treatment Example: community screening for chronic disease risk factors, lifestyle change intervention programs, prenatal screening programs |
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Tertiary Prevention
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Reduction of long-term impairment and disabilities and prevention of repeated episodes of clinical illness
Example: physical rehabilitation programs, lifestyle change programs for persons after recovery from an episode of clinical disease |
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Rate
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The frequency of occurrence of epidemiological events in populations
In using rates in epidemiology, rates are used to compare epidemiologic events among populations It enables the comparison of populations on disease experience, infection, mortality, and participation in health-related behaviors or health services utilization. |
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RATE = Numerator X Multiplier
----------------------- Denominator |
The numerator is the number of epidemiologic events
The denominator is the population of interest The “multiplier” in a rate calculation is selected so that the computation generally yields a number in the range from 1-100 (or several hundred). |
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Multiplier
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By convention:
For several major vital statistics, such as birth rate, death rate, and infant mortality rate, the preferred multiplier is 1,000 The result is expressed as a “rate per 1,000” For individual diseases, the most common multiplier is 100,000 The result is expressed as a “rate per 100,000” |
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Mortality Rate
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Death rate in a population during a time period
Mortality rate formula: DEATHS x 1,000 ------- Population “deaths per 1,000 population” |
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Infant mortality rate
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Annual death rate among children less than one year of age in relation to live births in the same year
Infant deaths x 1,000 -------------- Live births “Infant deaths per 1,000 live births” Most commonly used measure for comparing health status among nations |
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Crude mortality rate
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mortality from all causes
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Death to case ratio
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Number of deaths attributed to a particular disease during a specified period divided by the number of new cases of that disease (identified during the same period)
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Maternal mortality rate
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Annual death rate among women from causes associated with childbirth in relation to live births in the same year
RATE=Maternal deaths X 100,000 --------------- Live births |
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maternal Death rate
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Doubled in past 10 years due to hemorrhage, preeclampsia and blood clots
15 per 100,000 live births (2005) |
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Maternal death rate: Race specific
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US black women was nearly four times the rate on non-hispanic whites (34.7 per 100,000 live births)
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Attack rate
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proportion of population that develops illness during an outbreak
New cases Expressed as percentage Specific INCIDENCE over a limited time interval |
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Prevalence rate
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proportion of the poulation that has a health condition at a point in time
Example: flu |
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Life expectancy
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Average number of expected years of life for a person of a given age
Assuming present patterns of mortality persist Life expectancy at birth for the total U.S. population in 2005 reached a record high of 77.9 years. The difference in life expectancy at birth between males and females has decreased on average one-tenth of a year every year since 1980. The difference between male and female life expectancy remained 5.2 years greater for females in 2005, the smallest difference since 1946 |
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Age Adjustment
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Age adjustment is used to compare risks of two or more populations at one point in time or one population at two or more points in time. Age-adjusted rates are computed by the direct method by applying age-specific rates in a population of interest to a standardized age distribution, in order to eliminate differences in observed rates that result from age differences in population composition. Age-adjusted rates should be viewed as relative indexes rather than actual measures of risk
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