Service Learning - Yang
Terms
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- What is Public Health?
- The science and practice of protecting and improving the health of a community, as by preventative medicine, health education, control of communicable diseases, application of sanitary measures, and monitoring of environmental hazards.
- Pre-Christian period
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Disposal of the dead
Most tribes used quarantine
Minoans (300 -1500 B.C.) & Cretans (3000 - 1000 B.C.) had drainage systems and water flushing systems - Roman Empire
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public sanitary services, underground combined sewerage systems
excellent aqueducts still in use - Great Public Health Achievements-United States 1900-1999
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Public health policies have added 25 years to the life expectancy of people in the United States.
Immunizations
Motor vehicle safety
Workplace safety
Control of infectious disease
Decline in deaths from coronary heart disease and stroke
Safer and healthier foods
Healthier mothers and babies
Family Planning
Fluoridation of drinking water
Recognition of tobacco use as a health hazard - ( Dr. Lister/
- surgery disinfectant
- Dr.Lind
- British Navy and scurvy
- Dr. Semmelweis
- fever
- Epidemiology
- Study of factors that determine the occurrence and distribution of disease. The study of disease at the level of population
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Preventable Causes of Disease
BEINGS⬝ model -
Biologic and behavioral factors
Environmental
Immunologic
Nutritional
Genetic
Services, Social and spiritual factors - Agents of disease and illness
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Biologic
Bacteria, viruses, allergens, high fat diet etc.
Chemical
Lead, silicosis, asbestos
Physical
Radiation, heat, noise, cold
Environmental
Sanitation, social, political, and economic factors
Social and psychologic stressors - Herd Immunity
- when a vaccine not only prevents the vaccinated person from contracting the disease but also prevents them from spreading disease
- So if there is no herd immunity against disease and everyone is susceptible, the number of cases will ________each disease generation.
- double
- If there is 50% herd immunity, the number of cases ________each disease generation.
- remain the same
- If there is greater than 50% immunity than the disease ______.
- should eventually die out
- Negative consequence of Immunization
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Loss of “natural booster†phenomenon
(effect may be lost when immunization prevents exposure and occurrence of the disease in the future should immunity wane occur) - Iceberg Phenomenon
- The iceberg phenomenon denotes that the most severe cases of a disease, though less numerous, are the most visible and receive the most attention; yet the milder more abundant illnesses may go undetected. “Hidden beneath the surfaceâ€
- Negative Effects
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Change one element in the system, change will occur in other parts
e.g, Oral Polio Vaccine (Sabin) in the U.S
. - Incidence
- frequency (number) of new occurrences of a disease, injury, or death in the study population during the time period being examined!
- Prevalence
- the number of persons in a defined population who have a specified disease or condition at a point in time (time of survey).
- Risk
- proportion of persons who are unaffected at the beginning of a study period who undergo the risk event (death, disease, or injury) during the study period
- Cohort
- Clearly defined group of persons who are studied over a period of time, persons at risk for the event.
- Incidence rate
- The number of incident cases over a defined study period, divided by the population at risk at the midpoint of that study period
- Prevalence rate
- actually the proportion of persons with a defined disease or condition at the time they are studied.
- Commonly Used rates
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Infant mortality rate (IMR): Often used as an overall index of the health status of a nation.
Number of deaths to infants under 1 year of age/ Number of live births X 1000 - Preventative Medicine
- Preventative medicine seeks to enhance the lives of individuals by helping them protect and improve their own health
- Health
- state of complete physical, mental and social well-being and not merely the absence of disease or infirmity. (preamble to the constitution of WHO)
- Primary prevention
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Health promotion and specific prevention
Immunizations - Secondary prevention
- Screening tests, periodic health examinations
- Tertiary prevention
- Disability limitation and rehabilitation
- Accuracy
- the ability of a measurement to be correct on the average
- Precision
- ability of a measurement to give the same result or a very similar result with repeated measurements of the same thing. ( precision or reliability)
- Type I or alpha error-false positive error
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Something said to be true and is false
Example: VDRL and pregnancy - Type II or beta error-false negative error
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Something said to be false and it is true
Example: HIV testing - Sensitivity
- Ability of a test to identify disease when it is present in a diseased individual. If a test is NOT sensitive it will fail to detect disease in some diseased patients, this is the false negative error rate. Often as a test’s sensitivity rises it’s specificity decreases!
- Specificity
- Ability of a test to identify the absence of disease in nondiseased individuals. If a test is NOT specific it will falsely indicate the presence of disease in non-diseased individuals. This is called the false positive error rate. The more specific a test, the more readily it will yield negative results.
- Predictive Values
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help answer the questions, if a test is positive what is the probability that he or she actually has the disease. If a result is negative what is the probability that the patient does not have the disease.
Positive predictive value
Negative predictive value -
sensitivity - a/(a+c)
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specificity - d/(b+d)
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positive predictive value - a/(a+b)
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false positive error rate - b/(b+d)
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false negative error rate - c/(a+c)
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negative predictive value - d/(c+d)