2019HSCShort answer

Q33 (c)

3 marks

Question

A large epidemiological study was conducted. It used historical data to investigate the association between Herpes simplex virus (HSV) infection and dementia. Dementia is caused by a variety of brain illnesses. Alzheimer’s disease is the most common cause of dementia.
The study used the records of 8362 patients with HSV infection and 25 086 randomly selected sex- and age-matched control patients without HSV infection. Some of the patients with HSV had been treated with antiviral medication.
The graph below shows some results of the study.

Describe the trends shown in the data.

Uncropped source page 30 for question 33.c; requires human review and cropping — Reviewed visual · source page 30

Try the question before revealing the answer.

Solution

Criteria	Marks
Describes trends in the data	3
Outlines trends in the data	2
Provides some relevant information	1

Sample answer:

Patients with untreated HSV infection have an increased risk of developing dementia each year compared to patients who are not infected or are treated. Both treated and untreated HSV infection groups show a sharp increase in the risk of dementia after 10 years, but the untreated HSV group increases to more than double the risk of the treated HSV group. The group that did not have HSV infection only has a very small increase in risk after 10 years.

Supplied marking guidance · human reviewed

Compare this with your working, not only your final sentence.

Syllabus alignment

Module 8 · Non-infectious Disease and Disorders

EpidemiologyAnalyse incidence and prevalence patterns of non-infectious diseases in populations.

Spot a problem? Send feedback