Lecture 5 Epidemiology and biostatistics.ppt
- 1. Lecture 5 Epidemiology and Biostatistics
- 2. After completion the lecture the students enable to: 1. Describe the concept of Biostatistics, prevalence incidence, and health indicators. 2. Identify the four stages of a disease or health condition. 3. Explain the host, agent, and environment model. 4. Distinguish between incidence and prevalence in health and illness states.
- 3. Biostatistics: Is the science of statically measuring population health conditions. - Biostatistics is the primary public health measurement and analytic science underlying community health practice. - Biostatistics helps to describe the extent and distribution of health, illness, and conditions in the community. - Biostatistics aids in the identification of specific health problems and community strengths. .
- 4. A few Statistics Rate, ratio, incidence, and prevalence are common terms used to help describe illness and disease among population groups . A rate: A statistical measures expressing the proportion of persons with a given health problem among a population at risk. Number of events A rate is= --------------------X100,000 Population at risk . A ratio: A ratio: is often used to compare one at- risk population with another .
- 5. Mortality: Death rate . Morbidity: Illness rate . Mortality and morbidity statistics are collected routinely and used as indicators of the frequency of deaths and disease as they occur in time, place, and persons. .
- 6. Incidence and Prevalence Rates Incidence: Refers to the rate at which a specific disease develops in a population. An incidence rate is the number of new cases of an illness or injury that occurs in a specific time. Number of persons developing a disease Incidence rate=------------------------------------- X 100,000 Total number at risk per unit of time.
- 7. Prevalence: measures all of the existing cases at a given poinin of time . Prevalence includes the incidence (new cases) plus all of the existing cases. The prevalence rate is influenced by how many people become ill, and by the number of people who die or do not recover. Number of persons developing a disease Prevalence rate= --------------------------------- X100,000 Total number at risk per unit of time
- 8. SOURCES OF INFORMATION Epidemiologic investigators may draw data from any of three major sources: (1)existing data, (2)informal investigations, (3) scientific studies.
- 9. 1) Existing Data A variety of information is available nationally, by state, and by section, such as county, region, or urbanized area. a. Vital Statistics Vital statistics refers to the information gathered from ongoing registration of births, deaths, adoptions, divorces, and marriages. Sources for vital statistical information include state Web sites on the Internet, local and state health departments, city halls, and county halls of records
- 10. b. Census Data Data from population censuses taken every 10 years in many countries are the main source of population statistics.. Population statistics can be analyzed by age, sex, race, ethnic background, type of occupation, income gradient, marital status, educational level, or other standards, such as housing quality.
- 11. c. Reportable Diseases Each state has developed laws or regulations that require health organizations and practitioners to report to their local health authority cases of certain communicable and infectious diseases that can be spread through the community. All states require that diseases subject to international quarantine regulations be reported immediately.
- 12. d. Disease Registries Some areas or states have disease registries or rosters for conditions with major public health impact. Tuberculosis and rheumatic fever registries were more common when these diseases occurred more frequently.. e. Environmental Monitoring State governments, through health departments or other agencies, now monitor health hazards found in the environment. Pesticides, industrial wastes, radioactive or nuclear materials, chemical additives in foods, and medicinal drugs have joined the list of pollutants
- 13. Health Indictors Definition: Health indicators are standardized measures by which to compare health status and health system performance and characteristics among different jurisdictions in country
- 14. Categories of Health Indictors Categories of health indictors Mortality and burden of disease Ex: Access data on life expectancy, child mortality, morbidity.. Health services coverage Ex: Access data on skilled birth attendance, antenatal care, TB detection/treatment... Health systems resources Ex: Access data on health workforce, hospital beds and health expenditure. Risk Factors Ex: Access data on water and sanitation, nutrition, tobacco use... Inequities Ex: Access data on inequities in health care and health outcome. Demographic and socioeconomic statistics as: Access data on total population, birth/death registration
- 15. CONCEPTS BASIC TO EPIDEMIOLOGY The science of epidemiology draws on certain basic concepts and principles to analyze and understand patterns of occurrence among aggregate health conditions.
- 16. 1. The host is a susceptible human or animal who harbors and nourishes a disease-causing agent. 2. Many physical, psychological, and lifestyle factors influence the host’s susceptibility and response to an agent. 3. Physical factors include age, sex, race, and genetic influences on the host’s vulnerability or resistance. 4. Psychological factors, such as outlook and response to stress, can strongly influence host susceptibility. 5. Lifestyle factors also play a major role. Diet, exercise, sleep patterns, and healthy or unhealthy habits I. Host, Agent, and Environment Model
- 17. Causative agents is factors that are present (eg, bacteria that cause tuberculosis, rocks on a mountain road that contribute to an automobile crash) or factors that are lacking The environment refers to all the external factors surrounding the host that might influence vulnerability or resistance. The physical environment includes factors such as geography, climate, weather, safety of buildings, water and food supply, and presence of animals The psychosocial environment refers to social, cultural, economic, and psychological
- 18. Risk To determine the chances that a disease or health problem will occur, epidemiologists are concerned with risk or the probability that a disease or other unfavorable health condition will develop.
- 19. Refererance Andresen, E., & Bouldin, E. D. (Eds.). (2010). Public health foundations: Concepts and practices. John Wiley & Sons
- 20. . Thanks