Module 9: Disease Prevention

Learning Outcomes

By the end of this module, you should be able to:

1. Describe ‘disease prevention’ as a core pillar of public health work.

• Disease prevention is a key focus of public health, aiming to reduce the burden of disease by preventing illness before it occurs, detecting it early, and minimising its impacts.

• It includes population-based and individual-based interventions.

• Prevention efforts are often organised within the healthcare system (e.g. immunisation, screening programs).

• While health promotion focuses on enabling people to increase control over their health, disease prevention focuses on specific risk factors and diseases.

2. Differentiate between primary, secondary, and tertiary prevention approaches.

3. Discuss the role of universal and targeted/selective approaches to prevention.

• Universal prevention:

  • Aims to reduce risk across the whole population.

  • Examples: national vaccination programs, clean water supply, public smoking bans.

  • Benefits: widespread reach, can change social norms.

  • Limitations: may provide small benefit to each individual, may not reduce inequity if access differs.

• Targeted (or selective) prevention:

  • Focuses on high-risk groups or individuals.

  • Examples: alcohol brief interventions in pharmacies, genetic testing for families with cancer risk.

  • Benefits: greater benefit per person, efficient for those most at risk.

  • Limitations: risk of stigma, may overlook moderate-risk populations.

• The Prevention Paradox (Rose, 2008):

  A large number of people at small risk may produce more cases of disease than a small number at high risk.

  • This means shifting the entire population’s risk slightly lower produces more impact overall.

Key Concepts

Disease Prevention Overview

• Focuses on reducing modifiable risk factors, detecting disease early, and minimising long-term impacts.

• Applies to both communicable and non-communicable diseases (NCDs).

• Combines behavioural, environmental, and policy interventions.

Non-Communicable Diseases (NCDs)

• Include cardiovascular disease, cancer, diabetes, chronic respiratory disease.

• Responsible for ~60% of global deaths (WHO).

• Largely preventable — up to 80% of heart disease, stroke, and diabetes, and 1/3 of cancers could be prevented by reducing shared risk factors.

Four major modifiable risk factors:

1. Tobacco use

2. Unhealthy diet

3. Physical inactivity

4. Harmful use of alcohol

Screening and Early Detection

• Secondary prevention tool — detects early disease before symptoms appear.

• Population screening programs in Australia include:

  • Breast cancer

  • Cervical cancer

  • Bowel (colorectal) cancer

Challenges:

• Under-utilisation (e.g. bowel screening participation ~40%).

• Lower participation in disadvantaged, Indigenous, and CALD communities.

Risks of screening:

• False positives → anxiety, unnecessary tests.

• False negatives → missed diagnosis.

• Over-diagnosis → unnecessary treatment.

Immunisation (Primary Prevention Example)

• The National Immunisation Program (NIP) protects against multiple vaccine-preventable diseases.

• Targeted by age, risk group, and exposure (e.g. infants, elderly, Indigenous Australians).

• Some vaccines require multiple doses to build long-term immunity (booster schedule).

Upstream vs Downstream Interventions

• Upstream approaches are more sustainable and equitable for long-term disease prevention.

Combination of Prevention Levels

• Effective disease prevention requires integration across all four levels:

  • Primordial: tackle systemic risk creation

  • Primary: reduce exposure and promote healthy lifestyles

  • Secondary: detect early signs

  • Tertiary: manage and rehabilitate

Reflective/Practice Questions

1. Identify four modifiable risk factors common to colorectal cancer, type 2 diabetes, and cardiovascular disease.

Answer:

• Tobacco use

• Unhealthy diet (high fat/sugar, low fibre)

• Physical inactivity

• Harmful use of alcohol

These can be found in credible sources such as the World Health Organization, Australian Institute of Health and Welfare, and Cancer Council websites.

Why prioritise these at a population level?

• They account for the majority of preventable deaths.

• Shared risk factors → shared prevention benefits.

• Reducing them improves health outcomes and reduces healthcare costs.

2. Why are certain ages and groups targeted in the National Immunisation Program?

Answer:

• Infants: immature immune systems; need protection early.

• Elderly: waning immunity and higher disease risk.

• Pregnant women: protect both mother and baby.

• Health workers and high-risk populations: prevent spread and exposure.

Multiple doses are scheduled for some diseases to build immunity over time and ensure long-term protection.

3. What level of prevention does screening align with?

Answer:

• Secondary prevention, as it aims to detect disease early before symptoms appear and intervene promptly to prevent progression.

4. What are the benefits of conducting screening at community pharmacies?

Answer:
Benefits:

• Easier access for the public

• No appointment required

• Reaches individuals who may not visit GPs

Limitations:

• Limited follow-up or diagnostic capacity

• May miss people not visiting pharmacies

Alternative screening locations:

• Mobile health units, community centres, workplaces, or digital screening initiatives.

5. What’s the difference between upstream and downstream interventions in NCD prevention?

Answer:

• Upstream: Targets social and environmental causes (e.g. food pricing, built environments).

• Downstream: Targets individuals after disease or risk has developed (e.g. counselling, medication).

When to use upstream approaches:

• When addressing root causes or widespread population risks.
  When to use downstream approaches:

• When providing personalised care or management for existing conditions.

Key Takeaways

• Disease prevention is a foundational goal of public health.

• Focuses on reducing risk, preventing onset, and mitigating impacts of disease.

• NCDs are the leading global health challenge — mostly preventable through shared risk reduction.

• Both universal and targeted approaches are necessary for equity and effectiveness.

• Integrating all levels of prevention and upstream actions creates long-term population health improvement.

Extra Practice Question

Question:
Explain the concept of the prevention paradox and how it informs population health strategies.

Answer:
The prevention paradox (Rose, 2008) states that a large number of people at a small risk can generate more cases of disease than a small number at high risk.
This means that public health strategies should focus on shifting the entire population’s risk distribution (e.g. through universal policies) rather than only targeting high-risk individuals.
Example: reducing average salt intake in food can prevent more cardiovascular events than only treating those with hypertension.