Exam 1 - Review Questions

Question 1

What is the main difference between observational and experimental study designs?

Answer 1

Observational: correlation studies (show it)

Experimental: involves intervention (change it)

Question 2

When are observational study designs like cohort, case-control, and cross-sectional studies more appropriate than randomized designs?

Answer 2

Observational studies are more appropriate when comparing people with similar characteristics and see the effects of long-term/over time.

Randomized design studies are more appropriate when testing new drugs, treatments, tests, technologies

Question 3

What is the difference between incidence and prevalence? What different information does each give about disease occurrence?

Answer 3

The incidence of disease represents the rate of occurrence of new cases arising in a given period in a specified population, while prevalence is the frequency of existing cases in a defined population at a given point in time.

Question 4

In a study where you wanted to explore potential risk factors for a disease, and where you had access to people with current disease, what would be the most appropriate study design?

Answer 4

Case-control study

it compares individuals with the disease to those without it, helping identify associated risk factors efficiently.

Question 5

If a friend told you that they heard the risk of getting the flu as a college student was 5%, what would you tell them to make this statement more correct?

Answer 5

The 1-year risk of influenza infection was 5% among college students

Question 6

What is a health behavior theory? How do these theories relate to the social-ecological model? (Hint: consider factors such as age, ethnicity, and educational status.)

Answer 6

Health behavior theory- explain why people act the way they do concerning their health.

The social cognitive theory relates to the social-ecological model. It stats that people are agents who can influence their environment and vice versa.

Question 7

What are the key constructs of the health belief model? Practice applying these constructs to health behaviors related to a) nutrition choices; b) hygiene practices and infectious disease control; and c) high-risk sexual activity (e.g. multiple partners).

Question 8

According to the Transtheoretical Model (TTM), what are the key stages of change and what are some ways people can move between stages?

Answer 8

Precontemplation – not thinking about change

Contemplation – thinking about making a change

Preparation – getting ready to make a change (Within 30 days)

Action – has made a behavior change (<6 months)

Maintenance – has continued behavior change (>6 months)

Question 9

What type of virus is HIV? What features of HIV lead to its “success” in evading the immune system, and spreading to new hosts?

Answer 9

HIV is a human retrovirus- lentivirus

HIV replicates rapidly

Reverse transcriptase makes random errors leading to various strains

virulent and infectious strains of HIV are typically found in people who are in the late stages of infection

HIV is constantly changing

Question 10

What enzymes are involved in the HIV replication process?

Answer 10

reverse transcriptase

integrase

protease

Question 11

What are the target points for HIV drugs in the HIV life cycle?

Question 13

What are the three domains (Spheres) of the Social Cognitiive Theory? Apply the social cognitive theory to an HIV-related decision, such as the choice to (A) abstain from sexual intercourse, or (B) to be faithful to a single partner, or (C) to use a condom during sexual intercourse

Answer 13

Cognitive factors, behavioral factors, and environmental factors

Question 14

What are 4 goals of ART?

Answer 14

1. suppress HIV RNA (viral load level) as low as possible, for as long as possible
2. restore and preserve immune function. Increase CD4+ lymphocytes.
3. delay clinical progression of HIV disease. Reduce risk of illness with HIV-related infection or cancer, prolonging quality and length of life.
4. Prevent HIV transmission.

Question 15

What are the key regions affected by HIV/AIDS in 2024?

Answer 15

Eastern and Southern Africa

Western and Central Africa

Asia and the Pacific

Question 16

What are the key populations affected by HIV/AIDS in 2024?

Answer 16

Globally 46% of all new HIV infections were among women and girls in 2022.

In sub-Saharan Africa, adolescent girls and young women accounted for more than 77% of new infections among young people aged 15-24 years in 2022.

Question 17

How can political organizations coordinate to address the HIV/AIDS pandemic?

Answer 17

They can send money and promote the awareness of the pandemic

Question 18

What is a mediator? What is an effect modifier? Why are mediators and effect modifiers important to understand when assessing risk factors for HIV risk?

Answer 18

Mediators explain a casual relationship.

Effect modifiers explain factors that influence or modify the casual relationship.

Ethnicity, poverty, gender relations, and geographic region have also been identified as risk factors and have fueled the epidemic among vulnerable populations around the globe.

Question 19

What are some behavioral risk factors that are important to measure and understand in a study about male circumcision and HIV risk?

Answer 19

of sexual partners, condom use, frequency Of risky sex

Question 20

How would fear of disclosing HIV status impair the lives of women living with HIV, and also increase the risk of HIV infections?

Answer 20

Leading to shame, not being accepted, and losing family/friends. It would increase the risk as they would still maintain sexual practices without their partners knowing.

Question 21

What are some key socio-cultural factors that are shaping the HIV epidemic in South Africa?

Answer 21

Significant stigma has become a barrier for individuals to disclose their status to their partners or seek care and treatment, even when treatment for HIV is very effective in preventing the spread of infection.

Among many populations, the individual desire and family/community pressure to produce offspring can result in a lowered incentive for condom use.

Depression has been shown to increase an individual’s tendency for risk.

The intersection of Western and
Traditional African cultures resulted in a transformed Zulu identity that has been fractured and challenged by structural violence, especially targeting the Zulu groups

Prostitution and unsafe medical injection became widespread; patterns of concurrent sexual relationships developed or were maintained out of the interaction between economic needs, a mixture of traditional cultural patterns, and their interplay in gender-related and other politics.

Question 22

Describe two reasons why a sociocultural lens is necessary to take when developing HIV intervention strategies.

Question 23

What are the three interventions to HIV we went over? How can you relate them to the ecological framework?

Answer 23

PReP

Human rights; Multifaceted

Mother-to-child transmission: drug

Question 24

What is the epidemiologic concept of bias? How does it play a role in experiments?

Answer 24

A deviation of results or inferences from the truth or processes leading to such deviation.

Question 25

How can we control for bias in experiments? Can you give an example?

Answer 25

We can control for bias by doing randomized controlled trials (RCT). This randomly allocates groups that are likely to be similar on all measured and unmeasured variables.

Question 26

What is equipoise? How does it relate to RCTs?

Answer 26

Equipoise is the ethical prereq of an RCT.

Theoretical equipoise: no preference between treatments for the investigators

Equipoise is particularly relevant in RCTs, where participants are randomly assigned to different treatment groups. In an RCT, researchers must have a genuine uncertainty or equipoise regarding the comparative effectiveness of the interventions being studied.

Question 27

What is a Kaplan-Meier plot? what does it measure? Practice reading and interpreting the Kaplan-Meier plot from the lecture.

Answer 27

A Kaplan-Meier plot shows the survival function, which estimates the probability of survival over time.

Question 28

Describe some of the challenges that limited nevirapine updates in Low and middle-income countries in the early 2000s, after this lifesaving treatment was deemed efficacious.

Answer 28

Individual governments need to set policies.

Donors needed to organize to procure drugs.

Health systems needed to create protocols and internal systems.

Health workers needed to be trained in protocols.

Voluntary Counseling and Testing (VCT) services needed to be greatly expanded.

Women needed to opt for VCT

Women needed to deliver babies within prepared health systems

Question 29

Define and apply the key components of a logic model (Inputs, activities, outputs, outcomes).

Question 30

What is an indicator, and when is it used in measuring the impact of public health programs?

Answer 30

An indicator is an observable measure of outcomes or other study constructs. An example of an indicator is a depression severity score on a depression scale. It is used to measure the impact of public health programs when they can see benchmarks or levels that are met.