Descriptive Studies - Community Medicine - Lecture Slides, Slides of Medicine

Download Descriptive Studies - Community Medicine - Lecture Slides and more Slides Medicine in PDF only on Docsity! Descriptive Studies: Person, Place and Time Docsity.com Descriptive Epidemiology • Includes activities related to characterizing the distribution of diseases within a population Analytical Epidemiology • Concerns activities related to identifying possible causes for the occurrence of diseases Docsity.com Person • WHO is getting the disease? • Many variables are involved and studied, but factors such as sex, age & race often have a major effect. Docsity.com Characteristics of Person • Age • Sex • Ethnic group • Socioeconomic status • Nativity • Religion • Marital status • Occupation Docsity.com 10-14 15-19 20+ 5-9 g o g f + ' s : 3 8 ¢ 8 & 2 ~ -NOLLW1NdOd 000'001 Hd SASVO GaLYOdSY Time • WHEN does the disease occur? “Temporal” Range from hours to decades • Type of disease dictates “time” element to be used • Graphic format often used  y-axis (vertical) - frequency  x-axis (horizontal) - time Docsity.com O° ° O° S3S¥3 40 YIGWNN SEPTEMBER Characteristics Relating to Time • Secular change (long-term) • Point epidemics (short-term) • Cyclic trends • Seasonal variation Docsity.com Point Epidemics • Short-term changes occur over limited time frames  Hours  Days  Weeks  Months • Used for short-term exposures or diseases with short incubation and/or illness durations Docsity.com 2-3. 45 6-7 August  _ o Es WY, 1] YT... eee: as Ga ge | te tee Week of Onset 9 8 7 6 5 4 3 2 1 0 Seasonal Variation • Seasonal variation can be seen for some diseases or conditions falling within a calendar year Docsity.com Seasonal Variation • Seasonal variation can be used to suggest possible etiology. Migratory Birds? Docsity.com Time Clustering • Time clustering data can sometimes be used to trace the “beginning” to the introduction of a specific causal agent  Thalidomide & birth defects First marketed in Europe in 1950’s as sleeping pill and to treat morning sickness in pregnant women  Toxic Shock Syndrome Staphylococcus aureus infection in women using newly introduced hyperabsorbent tampons Docsity.com John Snow and Cholera Docsity.com 5 Criteria of Place •  Rate observed in all ethnic groups in the area •  Rate NOT observed in persons of similar groups inhabiting other areas • Healthy persons entering area get ill at same frequency • People who leave do NOT show similar levels • Similar levels of infestation in other species (if zoonotic disease) Docsity.com Characteristics Relating to Place • International • Variation within countries  Urban-rural  Local • Building Maps Docsity.com & Moderate to heavy colonies of S. marcescens kK O O O O ¢ O * * ® e Interactions of Time and Place • Time-place clustering • Migration Docsity.com