Inhalation or ingestion of asbestos fibres (chrysotile, crocidolite, amosite). Less common: erionite (a similar fibrous mineral) and high-dose radiation.

Largely palliative. Pleurectomy and extrapleural pneumonectomy in selected patients. Chemotherapy with pemetrexed plus cisplatin.

Asbestos was progressively banned in Australia from 1989; total ban in 2003. Home renovators remain at risk; pre-1990 buildings should be tested before renovation.

What is iodine deficiency?

Causes goitre and congenital cretinism. Reduced markedly in Australia by iodised salt and iodised baker's flour.

What is folate deficiency?

Causes neural tube defects in fetuses. Reduced by mandatory folate fortification of bread flour (Australia, 2009).

What is vitamin D deficiency?

Causes rickets in children and osteomalacia in adults. Reappearing in heavily veiled or housebound populations.

What is lead poisoning?

Causes neurological damage in children. Reduced by removal of lead from petrol (1986 to 2002) and house paint.

What is air pollution?

PM2.5 from traffic and bushfires causes COPD and ischaemic heart disease. Black Summer (2019 to 2020) bushfire smoke caused approximately 400 excess deaths in eastern Australia.

What are generic "lifestyle" risk factors?

Markers want specific mechanisms: smoking causes endothelial damage and oxidative stress; LDL promotes foam cell formation; hypertension shears the endothelium.

What is match depth to the command word?

"Outline" = brief cause; "describe" = the mechanism in order; "compare" = the same features for two diseases side by side; "assess"/"evaluate" = a justified judgement, not a list.

What is separate cause, mechanism and effect?

Examiners reward a clear chain. State the cause (exposure or dietary imbalance), the mechanism (what goes wrong in the cells/vessels), then the effects (the clinical outcomes).

What is use real Australian data for burden?

Quoting figures (around 1.3 million with T2DM, around 42 000 CVD deaths per year, around 700 to 800 mesothelioma cases per year) shows the epidemiological awareness NESA expects in this module.

§-Syllabus dot point

NSWBiologySyllabus dot point

Inquiry Question 2: Do non-infectious diseases cause more deaths than infectious diseases?

Investigate the causes and effects of named nutritional and environmental diseases, including diabetes (type 2), cardiovascular disease and mesothelioma

A focused answer to the HSC Biology Module 8 dot point on nutritional and environmental disease. Covers type 2 diabetes, cardiovascular disease (atherosclerosis) and mesothelioma, with mechanisms, risk factors and burden of disease in Australia.

Generated by Claude Opus 4.814 min answerUpdated 2026-06-28

Reviewed by: AI editorial process; not yet individually human-reviewed

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What this dot point is asking
The answer
Examples in context

What this dot point is asking

NESA wants you to describe the causes, mechanisms and effects of named nutritional and environmental diseases. Type 2 diabetes, cardiovascular disease and mesothelioma cover the three main categories: metabolic-nutritional, lifestyle-related and toxic environmental exposure.

The command words matter. "Outline" wants the cause in brief; "describe" wants the mechanism in order; "compare" wants the same features for two diseases; and "assess" or "evaluate" want a justified judgement. The highest-value skill is being able to trace a clear cause → mechanism → effect chain for each named disease.

The answer

Type 2 diabetes mellitus

Burden. Approximately 1.3 million Australians have type 2 diabetes (T2DM); around 5 percent of adults. The number is rising with obesity rates.

Causes.

Genetic. Family history doubles risk. Susceptibility variants in TCF7L2, KCNQ1 and others.
Lifestyle. Obesity (BMI over 30), sedentary behaviour, energy-dense diets high in refined carbohydrates and saturated fats.
Demographic. Age over 45, certain ancestries (Indigenous Australian, South Asian, Pacific Islander).
Gestational diabetes. History increases lifetime risk.

Mechanism. Insulin normally binds receptors on muscle, liver and fat cells, triggering glucose uptake via GLUT4 transporters. In T2DM, intracellular fat metabolites and inflammatory signalling impair insulin receptor signalling, producing insulin resistance. Beta cells compensate by hypersecreting insulin; over years they exhaust, glucose rises, and diabetes appears.

The mechanism below traces that cause-to-effect chain: excess energy and obesity drive insulin resistance, beta cells over-work then fail, blood glucose climbs, and chronic hyperglycaemia damages vessels throughout the body.

Effects. Chronic hyperglycaemia non-enzymatically glycates proteins, damaging blood vessel walls.

Microvascular. Retinopathy, nephropathy, peripheral neuropathy.
Macrovascular. Heart attack, stroke, peripheral vascular disease.
Other. Foot ulcers and amputation, recurrent infection, NAFLD, dementia risk.

Cardiovascular disease

Burden. Cardiovascular disease (CVD) is the leading cause of death in Australia, killing approximately 42 000 people each year. It includes coronary heart disease, stroke, heart failure and peripheral vascular disease.

Causes (risk factors).

Modifiable. Smoking, hypertension, dyslipidaemia (high LDL, low HDL), diabetes, obesity, sedentary behaviour, poor diet, excess alcohol, chronic stress.
Non-modifiable. Age, male sex, family history, certain ancestries.

Mechanism: atherosclerosis.

Endothelial injury. LDL cholesterol, hypertension, smoking and high glucose damage the arterial endothelium.
LDL infiltration. LDL enters the intima and is oxidised.
Foam cell formation. Macrophages engulf oxidised LDL, becoming foam cells.
Plaque growth. Smooth muscle cells migrate and proliferate. A fibrous cap forms over a lipid-rich necrotic core.
Stenosis or rupture. Plaques narrow the artery, reducing blood flow (angina). Rupture exposes the necrotic core to blood, triggering thrombosis. A coronary thrombus causes myocardial infarction (heart attack); a cerebral thrombus causes ischaemic stroke.

Effects.

Angina pectoris. Chest pain on exertion due to coronary artery narrowing.
Myocardial infarction. Death of cardiac muscle from sustained ischaemia.
Heart failure. Loss of cardiac output capacity after infarction.
Stroke. Loss of brain function from cerebral artery occlusion.

Management.

Lifestyle. Smoking cessation, dietary change (Mediterranean, DASH), exercise, weight loss.
Pharmaceutical. Statins (lower LDL), antihypertensives (ACE inhibitors, beta blockers), antiplatelets (aspirin, clopidogrel), anticoagulants in selected cases.
Procedural. Coronary angioplasty with stenting, coronary artery bypass grafting (CABG), valve replacement.

Mesothelioma

Burden: Australia has one of the highest mesothelioma incidence rates in the world (around 700 to 800 cases per year), driven by extensive historical asbestos use in construction and at the Wittenoom blue asbestos mine in Western Australia (operational until 1966).
Cause: Inhalation or ingestion of asbestos fibres (chrysotile, crocidolite, amosite). Less common: erionite (a similar fibrous mineral) and high-dose radiation.
Mechanism: Inhaled fibres less than 5 microns long penetrate the alveoli and are translocated to the pleura, where the body cannot clear them. They generate chronic inflammation and reactive oxygen species (ROS), which damage DNA and mutate tumour suppressor genes (BAP1, NF2, CDKN2A) in mesothelial cells. After a latency of 20 to 50 years, the accumulated mutations drive malignant transformation into mesothelioma. The cause-to-effect chain is drawn below.

Effects: Malignant pleural mesothelioma presents with chest pain, breathlessness from pleural effusion, weight loss and fatigue. The cancer is largely confined to the pleural cavity but is invasive, encasing the lung and resisting surgical removal. Peritoneal mesothelioma is less common and affects the abdominal cavity.
Management: Largely palliative. Pleurectomy and extrapleural pneumonectomy in selected patients. Chemotherapy with pemetrexed plus cisplatin. Immunotherapy (nivolumab plus ipilimumab) extends median survival modestly. Median survival from diagnosis remains under 12 months.
Prevention: Asbestos was progressively banned in Australia from 1989; total ban in 2003. Home renovators remain at risk; pre-1990 buildings should be tested before renovation.

Other nutritional and environmental diseases (worth knowing)

Iodine deficiency: Causes goitre and congenital cretinism. Reduced markedly in Australia by iodised salt and iodised baker's flour.
Folate deficiency: Causes neural tube defects in fetuses. Reduced by mandatory folate fortification of bread flour (Australia, 2009).
Vitamin D deficiency: Causes rickets in children and osteomalacia in adults. Reappearing in heavily veiled or housebound populations.
Lead poisoning: Causes neurological damage in children. Reduced by removal of lead from petrol (1986 to 2002) and house paint.
Air pollution: PM2.5 from traffic and bushfires causes COPD and ischaemic heart disease. Black Summer (2019 to 2020) bushfire smoke caused approximately 400 excess deaths in eastern Australia.

Worked exam answers

Worked example 1 - mesothelioma case (causal analysis)

Question. A 55-year-old former carpenter develops chest pain and breathlessness. Chest CT shows pleural thickening and effusion. Biopsy confirms epithelioid mesothelioma. He recalls cutting asbestos cement sheeting in the 1980s without respiratory protection. Analyse the cause and outline management.

Model answer.

Exposure: occupational inhalation of asbestos fibres approximately 35 years ago.
Mechanism: fibres lodged in the pleura, chronic inflammation, ROS-mediated DNA damage, tumour suppressor mutation, malignant transformation.
Latency: consistent with the 20 to 50 year window.
Management: pleural drainage for symptom relief, chemotherapy with pemetrexed plus cisplatin, palliative care, compensation through the Dust Diseases Tribunal.

Marker's note: marks are awarded for naming the exposure as the cause, for a correct mechanism that reaches malignant transformation, for recognising the latency, and for management that acknowledges the disease is largely palliative.

Worked example 2 - describe atherosclerosis leading to a heart attack (4 marks)

Question. Describe how atherosclerosis develops and leads to a myocardial infarction.

Model answer. Risk factors such as high LDL, smoking and hypertension damage the arterial endothelium, and LDL infiltrates the intima where it is oxidised. Macrophages engulf the oxidised LDL to become foam cells, smooth muscle proliferates, and a fibrous cap forms over a lipid-rich core - an atherosclerotic plaque. The plaque narrows the artery (stenosis); if it ruptures, the exposed core triggers thrombosis. A clot blocking a coronary artery stops oxygenated blood reaching part of the heart muscle, causing ischaemia and death of that cardiac muscle - a myocardial infarction.

Marker's note: 1 mark for endothelial injury + LDL oxidation, 1 mark for foam cells/plaque formation, 1 mark for stenosis/rupture and thrombosis, 1 mark for the blocked coronary artery causing cardiac muscle death. A description that stops at "plaque builds up" without the clot-and-ischaemia link caps at 2 to 3 marks.

Worked example 3 - environmental vs lifestyle judgement (3 marks)

Question. Justify whether mesothelioma or type 2 diabetes is more amenable to public health intervention.

Model answer. Both are preventable, but by different means. Mesothelioma is caused by a single environmental exposure (asbestos), so it is highly amenable to regulatory intervention - asbestos bans and safe-removal laws can prevent almost all new exposures, which is why incidence is expected to fall as historical exposure ages out. Type 2 diabetes is driven by lifestyle, so prevention depends on sustained individual behaviour change (diet, weight, activity), which is effective in principle but hard to maintain across a population. On the criterion of how reliably the cause can be removed, mesothelioma is more amenable to a clear regulatory fix; on sheer scale of preventable burden, type 2 diabetes intervention saves far more lives. A defensible conclusion either way earns the judgement mark, provided it is justified by the cause type.

Marker's note: 1 mark for a correct contrast of intervention type (regulation vs behaviour change), 1 mark for linking it to the cause of each disease, 1 mark for a justified judgement. An unsupported one-word answer earns nothing for the judgement.

Common traps

Saying type 2 diabetes is "caused by eating too much sugar." It is more accurately driven by chronic excess of total energy intake leading to obesity and insulin resistance. Refined carbohydrates contribute but are not the sole cause.

Confusing atherosclerosis and arteriosclerosis: Atherosclerosis is lipid plaque formation. Arteriosclerosis is general hardening of arteries.
Forgetting mesothelioma's latency: Diagnosis 30 to 50 years after a brief but high-dose exposure is typical.
Generic "lifestyle" risk factors: Markers want specific mechanisms: smoking causes endothelial damage and oxidative stress; LDL promotes foam cell formation; hypertension shears the endothelium.
Giving a symptom instead of a cause: When asked for the "cause" of an environmental disease, name the exposure (asbestos, UV, smoke), not the symptom (chest pain, breathlessness).

Exam technique

Always name the disease: When NESA asks you to outline the cause of "a nutritional/environmental disease", marks are lost if you describe a mechanism but never name a specific disease.
Match depth to the command word: "Outline" = brief cause; "describe" = the mechanism in order; "compare" = the same features for two diseases side by side; "assess"/"evaluate" = a justified judgement, not a list.
Separate cause, mechanism and effect: Examiners reward a clear chain. State the cause (exposure or dietary imbalance), the mechanism (what goes wrong in the cells/vessels), then the effects (the clinical outcomes).
Use real Australian data for burden: Quoting figures (around 1.3 million with T2DM, around 42 000 CVD deaths per year, around 700 to 800 mesothelioma cases per year) shows the epidemiological awareness NESA expects in this module.

Note

Your body usually keeps blood sugar steady using a hormone called insulin, which acts like a key that lets sugar into your cells. In type 2 diabetes, years of too much food and too little exercise make the locks stop responding to the key, so sugar builds up in the blood and slowly wrecks blood vessels - that is why it harms eyes, kidneys, nerves and the heart. Heart disease is mostly about pipes getting furred up: cholesterol builds fatty plaques inside arteries, like grease clogging a drain, and if a plaque cracks, a clot can block the pipe and starve the heart, causing a heart attack. Mesothelioma is different - it is caused from the outside. Tiny asbestos fibres get breathed in, stick in the lining around the lungs like splinters that never come out, and after 20 to 50 years of irritation they trigger a cancer. The big lesson: some diseases come from how we live, and some come from what we are exposed to - and that changes how we prevent them.

Examples in context

Example 1. Mesothelioma in James Hardie former employees and the asbestos register. James Hardie Industries manufactured asbestos cement products at sites including Camellia in Sydney's western suburbs from the 1930s to the 1980s. Former workers who inhaled crocidolite or chrysotile fibres typically developed mesothelioma 30 to 50 years later. Fibres less than 5 microns long penetrate alveoli and are translocated to the pleura, where they cannot be cleared and induce chronic inflammation and DNA damage in mesothelial cells. The Australian Mesothelioma Registry tracks roughly 700 new cases per year, with median survival under 12 months from diagnosis. The James Hardie compensation fund, established in 2007 after extensive litigation, provides ongoing support to affected workers and their families.

Example 2. Atherosclerosis in a 55-year-old Sydney commuter. A NSW Health typical cardiovascular case is a 55-year-old man with LDL cholesterol of 4.5 mmol/L, blood pressure 145/95, BMI 31 and a 30-pack-year smoking history. Over 30 years, oxidised LDL particles infiltrate the intimal layer of his coronary arteries, attract macrophages that engulf LDL to become "foam cells", and develop into atheromatous plaques. As plaques grow, they narrow the coronary lumen and the endothelium becomes vulnerable to rupture. A plaque rupture exposes thrombogenic material, a clot forms, blood flow to a section of myocardium ceases, and the patient has a myocardial infarction. Management uses statins, antihypertensives, and lifestyle change, addressing the multiple modifiable risk factors simultaneously.

Exam-style practice questions

Practice questions written in the style of NESA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

2024 HSC2 marksOutline the cause of a disease due to environmental exposure. (Name the disease.)

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Two marks for naming an environmental disease and outlining its cause (an environmental exposure, not a symptom). Sample: Lung cancer can be caused by exposure to (inhalation of) smoke from cigarettes. Markers penalise naming a pathogen-caused or genetic disease instead of an environmental one, or giving a symptom rather than a cause. Other valid examples include mesothelioma from asbestos exposure or skin cancer from UV exposure. Source: NESA 2024 HSC Biology examination and marking guidelines.

Practice questions

Original practice questions graded from foundation to exam level, each with a full worked solution. Try them before revealing the solution.

foundation2 marksDistinguish between a nutritional disease and an environmental disease, giving one named example of each from this dot point.

Show worked solution →

1 mark - nutritional disease. A nutritional disease is caused by an imbalance in the diet (deficiency or excess of energy or nutrients). Example: type 2 diabetes, driven by chronic excess energy intake and obesity leading to insulin resistance.

1 mark - environmental disease. An environmental disease is caused by exposure to a harmful agent in the surroundings. Example: mesothelioma, caused by inhalation of asbestos fibres.

The mark hinges on tying the category to its cause (diet vs external exposure) AND naming a valid disease. Naming a disease without linking it to the correct cause caps at 1 mark.

foundation3 marksOutline the mechanism by which insulin resistance leads to chronic hyperglycaemia in type 2 diabetes.

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1 mark - normal insulin action: Insulin binds receptors on muscle, liver and fat cells, triggering glucose uptake (via GLUT4 transporters), which lowers blood glucose.
1 mark - insulin resistance: In T2DM the target cells respond poorly to insulin, so glucose uptake is reduced and glucose stays in the blood.
1 mark - beta-cell exhaustion: Pancreatic beta cells hypersecrete insulin to compensate, but over years they exhaust/fail, so insulin output falls and blood glucose rises further into the diabetic range.

Full marks need the chain: poor cell response → compensatory hypersecretion → beta-cell failure → sustained hyperglycaemia.

foundation2 marksState the cause of mesothelioma and explain why diagnosis usually occurs decades after exposure.

Show worked solution →

1 mark - cause. Mesothelioma is caused by the inhalation (or ingestion) of asbestos fibres that lodge in the pleura.

1 mark - latency. There is a long latency period of 20 to 50 years because the fibres cause slow, cumulative DNA damage (chronic inflammation and mutation of tumour suppressor genes) before a malignant tumour develops and produces symptoms.

An answer that names asbestos but cannot explain the delay (slow accumulation of mutations) earns only the cause mark.

core4 marksDescribe the process of atherosclerosis and explain how it can result in a myocardial infarction.

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Award up to 4 marks for a sequenced mechanism that links plaque formation to infarction.

1 mark - endothelial injury and LDL infiltration: Risk factors (high LDL, hypertension, smoking, high glucose) damage the arterial endothelium; LDL enters the intima and is oxidised.
1 mark - foam cells and plaque growth: Macrophages engulf oxidised LDL to become foam cells; smooth muscle proliferates and a fibrous cap forms over a lipid-rich core (an atherosclerotic plaque).
1 mark - stenosis or rupture: The plaque narrows the artery (stenosis), reducing blood flow; if it ruptures, the exposed core triggers thrombosis (clot formation).
1 mark - infarction: A clot blocking a coronary artery stops blood (and oxygen) reaching part of the heart muscle, causing ischaemia and death of cardiac muscle - a myocardial infarction.

A response that describes plaque build-up but never reaches clot → blocked coronary flow → muscle death caps below full marks.

core5 marksCompare type 2 diabetes and mesothelioma in terms of their causes, the role of personal behaviour, and how amenable each is to public health intervention.

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Award up to 5 marks for a genuine comparison (both similarities and differences) across the three dimensions.

Causes (1-2 marks): T2DM is multifactorial and nutritional/lifestyle - genetic susceptibility plus obesity and inactivity producing insulin resistance. Mesothelioma is environmental and largely single-cause - inhaled asbestos fibres causing mutation. (Similarity: both are non-infectious and both involve cellular dysfunction.)
Role of personal behaviour (1-2 marks): T2DM risk is strongly modifiable by individual behaviour (diet, weight, exercise). Mesothelioma risk depends on exposure that is often occupational and beyond the individual's control, so personal behaviour plays a much smaller role.
Amenability to intervention (1-2 marks): T2DM is addressed by sustained behaviour change plus screening and medication - effective but reliant on long-term compliance. Mesothelioma is addressed by regulation (asbestos bans, safe-removal laws) - highly effective at prevention but offering little once exposure has occurred, since treatment is largely palliative.

A full-mark answer makes an explicit comparison on each dimension rather than describing the two diseases separately.

core4 marksType 2 diabetes prevalence in Australian adults rose from about 3.3 percent in 2000 to about 5.0 percent in 2024. Using the concepts of incidence and prevalence, explain two factors that could produce this rise.

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1 mark - define the terms: Incidence is the number of new cases in a period; prevalence is the total proportion of the population living with the disease at a point in time.
1 mark - rising incidence factor: Increasing obesity and sedentary lifestyles raise the incidence (more new cases of insulin resistance each year), pushing prevalence up.
1 mark - duration/survival factor: Earlier diagnosis and better management mean people live longer with the disease, so cases accumulate and prevalence rises even if incidence were steady.
1 mark - link: Prevalence reflects incidence multiplied by average disease duration, so a rise can come from more new cases, longer survival, or both; an ageing population (age over 45 is a risk factor) contributes to both.

Markers reward distinguishing "more new cases" from "people living longer with it" - both legitimately raise prevalence.

exam7 marksNon-infectious diseases now cause the majority of deaths in Australia. Using type 2 diabetes, cardiovascular disease and mesothelioma as examples, assess the relative importance of lifestyle factors versus environmental factors in causing the burden of non-infectious disease.

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"Assess" requires a judgement about the relative importance of lifestyle versus environmental causes, supported by the three named diseases. A Band 6 response reaches a reasoned, qualified conclusion.

Lifestyle-driven burden (2-3 marks): Type 2 diabetes and most cardiovascular disease are driven by modifiable lifestyle factors - obesity, poor diet, inactivity, smoking, dyslipidaemia. These account for a very large share of mortality (CVD alone kills around 42 000 Australians per year; T2DM affects around 1.3 million). Because they are widespread and behaviour-linked, lifestyle factors dominate the total burden of non-infectious disease.
Environmentally-driven burden (2-3 marks): Mesothelioma is almost entirely environmental (inhaled asbestos), causing around 700 to 800 cases per year - a much smaller absolute burden, but severe, near-untreatable and clearly attributable to a single exposure. Other environmental contributors (air pollution PM2.5, UV radiation, lead) add to the total.
Judgement (1-2 marks): A supported conclusion: lifestyle factors are the more important driver of the overall burden because they underlie the highest-mortality diseases (CVD, T2DM) and affect millions; however, environmental factors are critical for specific high-lethality diseases like mesothelioma and are often more preventable by regulation than lifestyle disease is by behaviour change. An answer that lists factors without weighing them, or omits one disease, caps below full marks.

exam6 marksEvaluate the effectiveness of public health strategies in reducing the burden of cardiovascular disease in Australia.

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"Evaluate" requires a judgement on effectiveness, weighing evidence of success against ongoing limitations.

Strategies and evidence of success (2-3 marks): Public health strategies include tobacco control (plain packaging, taxes, smoking bans), dietary campaigns (reducing salt and saturated fat), blood-pressure and cholesterol screening, and subsidised statins and antihypertensives. The evidence of effectiveness is strong: CVD mortality fell from around 380 per 100 000 (1980) to around 70 per 100 000 (2024) - a dramatic decline reflecting reduced smoking, better risk-factor control and improved emergency care (stents, thrombolysis).
Limitations weighed (2-3 marks): Despite the fall, CVD remains the leading cause of death; declines have plateaued as obesity and type 2 diabetes rise, and inequities persist (higher rates in Indigenous, rural and low-income groups). Behaviour-change programs rely on sustained individual compliance, which is hard to maintain.
Judgement (1 mark): A supported conclusion: public health strategies have been highly effective (mortality cut by roughly 80 percent since 1980) but are incomplete - rising obesity/diabetes and persistent inequities mean continued, targeted intervention is needed. A descriptive list without a judgement on effectiveness caps below full marks.