Download Free Medical Hiv Prevention PowerPoint Presentation

Hiv Prevention PowerPoint Presentation

DOWNLOAD MEDICAL POWERPOINT PRESENTATION

About This Presentation

Description : Hiv prevention public health

Tags : Hiv,terminology,Breast cancer,cancer

Published on : Jul 09, 2021 | Views : 1859 | Downloads : 0

Shareable Url :

Embed Code :

Comment

Transcript

Slide 1-

Measures of effect or association Dr Sumaya Mall Division of Epidemiology and Biostatistics School of Public Health University of the Witwatersrand Sumaya.mall@wits.ac.za
Slide 2-

Note on terminology Sometimes in the epidemiological literature, you might see the term ‘measures of association’ I prefer ‘measures of effect interested in knowing not only whether a link between a given exposure (e.g. smoking) and a certain outcome (e.g. myocardial infarction) is statistically significant, but also the magnitude of this relationship.
Slide 3-

Aims of today’s lecture Recap of the past two days Define and discuss measures of effect both relative and absolute Discuss specific measures of effect in relation to specific study designs Run through examples and calculations – use the example of breast disease
Slide 4-

Revision/Recap of the last two days
Slide 5-

How do we know statistically…? HIV infection is through sexual transmission? Smoking is related to cardiovascular disease? Childhood trauma is related to the onset of schizophrenia ?
Slide 6-

Relationships between exposures and disease HIV infection is through sexual transmission? Smoking is related to cardiovascular disease? Childhood trauma is related to the onset of schizophrenia ?
Slide 7-

Key to the field of epidemiology is…. Comparison !!!!! We always compare exposed and unexposed
Slide 8-

ppt slide no 8 content not found
Slide 9-

ppt slide no 9 content not found
Slide 10-

ppt slide no 10 content not found
Slide 11-

ppt slide no 11 content not found
Slide 12-

Measures of association/measures of effect Exposed people can have different levels and durations of exposure The total amount of a factor that reaches an individual is called the “dose.” We can then compare occurrences to calculate the risk that a health effect will result from an exposure. the measures describe the strength of an association between exposure and outcome.
Slide 13-

Breast cancer
Slide 14-

Breast cancer Breast cancer is a common cancer and leading cause of mortality Breast cancer incidence is increasing in low and middle income countries Recent literature suggests that there are some modifable risk factors for breast cancer
Slide 15-

Breast cancer
Slide 16-

ppt slide no 16 content not found
Slide 17-

Khalis et al (2020)
Slide 18-

ppt slide no 18 content not found
Slide 19-

ppt slide no 19 content not found
Slide 20-

Li et al (2020) Benign breast disease may lead to breast cancer and also to distress and reduced quality of life Common benign breast disease manifests as fibroadenoma or nodule of fibrous tissue often common in younger women Li et al aimed to explore if fibroadenoma is associated with risk factors common with breast cancer
Slide 21-

Li et al (2020)
Slide 22-

Li et al (2020)
Slide 23-

Calculations
Slide 24-

Cohort Study
Slide 25-

ppt slide no 25 content not found
Slide 26-

ppt slide no 26 content not found
Slide 27-

ppt slide no 27 content not found
Slide 28-

Let us calculate a risk ratio Also known as relative risk Risk in exposed/risk in unexposed Incidence in the exposed is a/a+b Incidence in the unexposed is c/c+d RR is incidence in exposed/incidence in unexposed
Slide 29-

ppt slide no 29 content not found
Slide 30-

ppt slide no 30 content not found
Slide 31-

ppt slide no 31 content not found
Slide 32-

ppt slide no 32 content not found
Slide 33-

Risk difference Instead of comparing two measures of disease frequency by calculating their ratio, one can compare them in terms of their absolute difference. The risk difference is calculated by subtracting the cumulative incidence in the unexposed group (or least exposed group) from the cumulative incidence in the group with the exposure. where (CIe) = cumulative incidence among the exposed subjects, and (CIu) is the cumulative incidence among unexposed subjects.
Slide 34-

ppt slide no 34 content not found
Slide 35-

ppt slide no 35 content not found
Slide 36-

ppt slide no 36 content not found
Slide 37-

ppt slide no 37 content not found
Slide 38-

ppt slide no 38 content not found
Slide 39-

ppt slide no 39 content not found
Slide 40-

ppt slide no 40 content not found
Slide 41-

ppt slide no 41 content not found
Slide 42-

Let us calculate an Odds Ratio In a case control study we do not know the incidence of disease SO we cannot calculate the RR OR is odds that an exposed person develops disease/odds that a non-exposed person develops disease (a/b)/(c/d)
Slide 43-

Let us calculate an Odds Ratio
Slide 44-

Let us calculate an Odds Ratio
Slide 45-

ppt slide no 45 content not found
Slide 46-

ppt slide no 46 content not found