Non-Infectious Disease
They cannot spread from person to person, yet they kill more people than all infectious diseases combined. Non-infectious diseases — heart disease, diabetes, cancer, asthma — are the silent epidemic of the modern world. Understanding their causes is the first step to prevention.
Before You Begin
Think about someone in your family or community who has a condition like asthma, diabetes, or heart disease.
Write down your answers before reading on:
- What factors do you think contributed to their condition?
- Could their condition have been prevented?
- How does their daily life differ from someone without the condition?
Know
- The main categories of non-infectious disease: lifestyle, genetic, environmental, degenerative
- Major non-infectious diseases affecting Australians
- Risk factors for non-infectious diseases
Understand
- How lifestyle choices influence disease risk
- The interaction between genetic and environmental factors
- Why non-infectious diseases are increasing globally
Can Do
- Identify risk factors for major non-infectious diseases
- Suggest evidence-based prevention strategies
- Explain why non-infectious diseases cannot be caught from others
Lifestyle Diseases
Choices that shape your health
Antimicrobial Resistance
Lifestyle diseases are non-infectious diseases strongly linked to personal behaviours and choices. They are sometimes called diseases of affluence because they are more common in wealthy countries with sedentary lifestyles and abundant processed food.
Major lifestyle diseases include:
- Cardiovascular disease (CVD): Heart attacks and strokes caused by a buildup of fatty deposits in arteries. Risk factors include smoking, unhealthy diet, physical inactivity, and obesity.
- Type 2 diabetes: The body becomes resistant to insulin or cannot produce enough. Strongly linked to obesity and physical inactivity.
- Chronic obstructive pulmonary disease (COPD): Progressive lung damage, mainly caused by smoking.
- Some cancers: Lung cancer (smoking), liver cancer (alcohol), bowel cancer (diet and inactivity).
The good news: lifestyle diseases are largely preventable. Not smoking, eating a balanced diet, being physically active, and maintaining a healthy weight dramatically reduce risk.
Genetic Diseases
When DNA holds the answer
Genetic diseases are caused by mutations in DNA that are inherited from parents or occur spontaneously. These diseases are present from birth (even if symptoms appear later) and cannot be prevented by lifestyle choices.
Examples include:
- Cystic fibrosis: A mutation in the CFTR gene causes thick mucus to build up in the lungs and digestive system. In Australia, about 1 in 2,500 babies is born with CF.
- Huntington's disease: A mutation causes progressive brain degeneration. Symptoms typically appear between ages 30 and 50.
- Sickle cell anaemia: A mutation in the haemoglobin gene causes red blood cells to become sickle-shaped, leading to pain and organ damage.
- Down syndrome: Caused by an extra copy of chromosome 21. It is the most common chromosomal condition in Australia.
While genetic diseases cannot be prevented, genetic counselling and screening can help families understand risks.
Environmental and Degenerative Diseases
External triggers and internal breakdown
Environmental diseases are caused or triggered by external factors:
- Asthma: Airways become inflamed and narrowed in response to triggers like pollen, dust mites, air pollution, or cold air. About 1 in 9 Australians has asthma.
- Mesothelioma: A cancer of the lung lining caused almost exclusively by asbestos exposure.
- Skin cancer: Caused by UV radiation from sun exposure. Australia has the highest skin cancer rates in the world.
Degenerative diseases involve the progressive breakdown of tissues or organs over time:
- Alzheimer's disease: Brain cells degenerate, causing memory loss and cognitive decline.
- Osteoarthritis: Cartilage in joints wears away, causing pain and stiffness.
Many diseases have multiple causes. For example, type 2 diabetes has genetic and lifestyle components. Lung cancer can be caused by smoking (lifestyle), asbestos (environmental), or genetics.
The Australian Burden
Non-infectious diseases in Australia
Non-infectious diseases dominate the Australian health landscape:
| Disease | Australian Impact |
|---|---|
| Cardiovascular disease | Kills 1 in 4 Australians; leading cause of death |
| Cancer | About 150,000 new cases annually; 1 in 2 Australians will be diagnosed by age 85 |
| Type 2 diabetes | 1.3 million Australians diagnosed; fastest-growing chronic condition |
| Asthma | 2.7 million Australians (11% of population) |
| Dementia | Over 400,000 Australians; second leading cause of death |
These diseases place enormous pressure on the healthcare system and economy. The Australian Institute of Health and Welfare estimates that chronic diseases account for most of Australia's health spending.
Prevention is cost-effective: reducing smoking, improving diet, increasing physical activity, and limiting alcohol consumption could prevent thousands of deaths and save billions of dollars annually.
Common Misconceptions
"Non-infectious diseases are not serious because they cannot spread." No — non-infectious diseases cause far more deaths than infectious diseases globally. Cardiovascular disease alone kills about 18 million people worldwide each year.
"Genetic diseases can be prevented by healthy living." No — genetic diseases are caused by inherited DNA mutations. While healthy living can manage symptoms, it cannot prevent the underlying genetic condition.
Chronic Disease in Indigenous Australia
The Closing the Gap health targets: Aboriginal and Torres Strait Islander Australians experience significantly higher rates of chronic non-infectious diseases than non-Indigenous Australians. Type 2 diabetes is 3-4 times more common, cardiovascular disease death rates are higher, and kidney disease is far more prevalent. These disparities reflect social determinants of health including education, employment, housing, and healthcare access rather than genetic differences.
The Indigenous Diabetes Health Circle: Community-led programs are showing promising results. In some regions, culturally appropriate education, exercise programs, and nutrition initiatives have improved diabetes management and reduced complications. The key insight is that effective prevention requires community control and cultural relevance.
Rheumatic heart disease: While rheumatic heart disease has virtually disappeared from non-Indigenous Australia, it remains a significant problem in remote Indigenous communities. It develops after untreated streptococcal throat infections damage heart valves. Prevention requires treating sore throats promptly — a challenge in communities with limited healthcare access.
✍ Copy Into Your Books
▾Lifestyle Diseases
- CVD, type 2 diabetes, COPD, some cancers
- Linked to smoking, diet, inactivity, obesity
- Largely preventable through healthy choices
Genetic Diseases
- Caused by inherited DNA mutations
- Examples: cystic fibrosis, Huntington's, sickle cell
- Cannot be prevented by lifestyle
Australian Statistics
- CVD = leading cause of death
- Cancer = 150,000 new cases/year
- Diabetes = 1.3 million Australians
- Asthma = 2.7 million Australians