{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture 02b.pptx - Lecture 2 Part II Measures of disease...

Info icon This preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 2 – Part II Measures of disease occurrence Ratios, proportions, rates Risk Incidence rates Prevalence
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
What is the pre-requisite for conducting epidemiologic investigations? Ability to quantify the occurrence of disease (outcome) What is the most basic measure of disease occurrence?
Image of page 2
City A has 100 hospitalizations for asthma and City B has 250 hospitalizations for asthma 1. Would you conclude that severe asthma is more common in City A or City B? 2. What do you need to account for to compare the occurrence of asthma in these two populations? Example
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
How can we quantify the occurrence of disease? Rates of occurrence allow us to quantify and compare burden of disease New cases of Hepatitis City A 58 City B 35 Requires knowledge of…
Image of page 4
Annual rate of occurrence of Hepatitis A City A: 58 per 25,000 per year City B: 35 per 14 000 for per year Apply Rate base: per 100, 1000, 10000…to achieve a whole number in the numerator Annual rates of hepatitis: City A = (58 /25,000) x 100,000 =232 cases* City B= (35 /14000) x 100,000 =250 cases* *(per 100,000 person-years)
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Ratios, Proportions, Rates Ratio: x/y - no relationship implied between numerator (x) and denominator (y) Example: sex ratios of stomach cancer 1960: 1.3 : 1 2006: 2.5 : 1 (male:female) Examples of mathematical parameters used to relate number of cases to size of source population
Image of page 6
Ratios, Proportions, Rates Proportion: x/y - Those who are in the numerator (x) are also included in the denominator (y) Example: proportion of fetal deaths 6.0 fetal deaths/1000 total number of births -Proportions can also be expressed as a percentage: i.e. percentage of fetal deaths=0.6%
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Ratios, Proportions, Rates Hypothetical Data from Queen’s University Issue: Anorexia Nervosa among university students Time Period Duration Students Cases early 1980’s 4 yrs 14,000 4 late 1990’s 3 yrs 17,000 4 Rate: x per y - relationship between x and y - y includes an element of time
Image of page 8
Ratios, Proportions, Rates Hypothetical Data from Queen’s University Issue: Anorexia among university students Common time period 1980-84 1 per year 1996-99 1.3 per year Common population size (denominator) 1980’s 1 per 14,000 per year = 0.7 per 10,000 per year = 7/10 5 /yr 1990’s 1.3 per 17,000 per year = 0.76 per 10,000 per year = 7.6/10 5 /yr
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Risk Perception, Incidence and Prevalence
Image of page 10
Risk Perception People have very different attitudes toward risk. There are two components of risk perception Probability that an adverse outcome will result from exposure (or activity). This is an epidemiological measurement Complex mixture of social and psychological factors
Image of page 11

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Incidence Deals with what is new Number of new events or cases of disease that develop in a population of individuals at risk during a specified time interval There are two specific types of incidence measures: Cumulative Incidence (CI) Person-Time Incidence Rate
Image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern