Descriptive Epidemiology - Health - Lecture Slides, Slides of Public Health

Download Descriptive Epidemiology - Health - Lecture Slides and more Slides Public Health in PDF only on Docsity! Descriptive Epidemiology docsity.com Learning Objectives: 1. Characterize the major dimensions of descriptive epidemiology: Person, Place, Time 2. Recognize how measurement and quantification of health outcomes by person, place, and time can assist in planning health services. 3. Recognize how measurement and quantification of health outcomes by person, place, and time can provide clues to etiology of health-related events. 4. Recognize the characteristics, strengths, and limitations of ecologic (aggregate) studies, case reports, and case series. docsity.com Person Since disease not does occur at random: What kinds of people tend to develop a particular disease, and who tends to be spared? What’s unusual about those people? docsity.com Person Age – the most fundamental factor to consider when describing disease occurrence. --- The incidence of most chronic diseases increases with age. --- However, the incidence of many infectious diseases is highest in childhood. --- Some disorders show bi-modal (two peak) distributions (i.e. Hodgkin’s disease). This may reflect different underlying etiologies. docsity.com Person Gender – biological and non-biological factors related to gender may impact disease risk. --- In all developed countries, life expectancy is higher in females and males – principally due to lower heart disease mortality. --- However, many chronic diseases occur more frequently in women (depression, lupus, etc.) --- As lifestyles continue to become more similar, a question is whether mortality rates will become more similar (i.e. environment vs. biology). docsity.com Discussion Question 1 What hypotheses might explain the highest incidence of severe mental illness among the lowest social classes? docsity.com Discussion Question 1 1. Social causation hypothesis: membership (and factors) in low social classes produces schizophrenia and other mental illness. 2. Social drift hypothesis: mental disorders are disabling – stigma and impaired income earning ability that occur with mental illness results in downward mobility. docsity.com Place Since disease not does occur at random: Where is the disease especially common or rare, and what is different about those places? Investigation by place includes: • Across countries (international) • Within country variation • Urban/rural differences • Localized areas docsity.com • Some differences in disease occurrence between urban and rural locations may be attributed to: --- Diet --- Physical activity --- Housing conditions (i.e. lead paint) --- Crowding (i.e. spread of infection) --- Pollution Place docsity.com • Some localized differences in disease occurrence may be attributed to: --- Carcinogenic exposure (i.e. radon) --- Geologic formations (i.e. water hardness) --- Lifestyle Place docsity.com Discussion Question 2 Regarding cross-country variation in disease occurrence, what is a likely impact of migrating from one’s native land to a geographically and culturally different location? docsity.com Time • Secular trends refer to gradual changes in disease occurrence over long periods of calendar time. --- Example: In the U.S., mortality from heart disease has been gradually declining, whereas cancer mortality has been gradually increasing. docsity.com Time • Cyclic fluctuations refer to shorter- term increases and decreases in disease occurrence over a period of years, or within a year. --- Fluctuations in respiratory infection deaths over a few years --- Seasonal variation of infections, heart attacks, etc. docsity.com Time • Point epidemic refers to increased disease occurrence among a group of people exposed almost simultaneously to an etiologic factor (i.e. pathogen, contaminant). --- Despite exposure at a common point in time, the actual time of disease onset may vary. docsity.com Cohort Effects Cohort effect: Long-term variation in disease occurrence among a group of persons who share something in common. i.e. • Occupational exposures during a specific time period. • Birth year or era and changes in lifestyle characteristics such as smoking habits. docsity.com Clustering Clustering: An unusual aggregation of health events grouped together in space or time. i.e. • Adverse reactions to vaccines • Outbreak of legionnaires’ disease in 1970’s • Early 1980’s – high number of cases of Kaposi’s sarcoma in young homosexual men docsity.com Clustering Clustering: Be careful where to identify a cluster because of chance variation. * * * * * * * * * * * * * * docsity.com