What is the difference between a communicable and non-communicable disease?

Communicable diseases are caused by pathogens (like bacteria or viruses) and can be transmitted from person to person, such as the flu or COVID-19. Non-communicable diseases (NCDs) are not infectious and cannot be spread. They are often chronic and result from a combination of genetic, lifestyle, and environmental factors. Examples include heart disease, cancer, and diabetes.

Can non-communicable diseases be cured?

Most NCDs cannot be cured, but they can often be managed or prevented. For example, type 2 diabetes can be controlled through diet, exercise, and medication, and in some cases, remission is possible. Cardiovascular disease can be managed with lifestyle changes and drugs. Prevention is key: avoiding smoking, maintaining a healthy weight, and eating a balanced diet significantly reduce the risk.

How does smoking cause non-communicable diseases?

Smoking damages the lining of blood vessels, leading to atherosclerosis (build-up of fatty plaques), which increases the risk of heart attacks and strokes. The chemicals in tobacco smoke also cause mutations in lung cells, leading to lung cancer. Additionally, smoking reduces lung function and can cause chronic obstructive pulmonary disease (COPD).

Why is obesity a risk factor for many non-communicable diseases?

Obesity, especially excess abdominal fat, leads to insulin resistance, which can cause type 2 diabetes. It also increases blood pressure and cholesterol levels, raising the risk of cardiovascular disease. Furthermore, obesity is linked to several cancers, including breast and colon cancer, possibly due to hormonal changes and chronic inflammation.

What is the difference between type 1 and type 2 diabetes?

Type 1 diabetes is an autoimmune condition where the immune system destroys insulin-producing cells in the pancreas, usually developing in childhood. It requires insulin injections. Type 2 diabetes is characterized by insulin resistance or insufficient insulin production, often linked to obesity and lifestyle. It can sometimes be managed with diet and exercise, but may also require medication.

How can I reduce my risk of developing cancer?

You can reduce cancer risk by avoiding tobacco, limiting alcohol consumption, protecting your skin from UV radiation, maintaining a healthy weight, eating a diet rich in fruits and vegetables, and staying physically active. Vaccinations (e.g., HPV vaccine) can prevent virus-related cancers. Regular screening can also detect cancers early when they are more treatable.

Non-communicable diseases in humans

WJEC

GCSE

This topic examines the causes and management of non-communicable diseases in humans, focusing on the interaction of various lifestyle factors. It covers the impact of exercise, diet, alcohol, smoking, and UV radiation on disease incidence, alongside the evaluation of medical treatments for cardiovascular disease.

Objectives

Exam Tips

Pitfalls

Key Terms

Mark Points

Topic Overview

Non-communicable diseases (NCDs) are long-term medical conditions that are not caused by infectious agents and cannot be transmitted from person to person. In humans, major NCDs include cardiovascular diseases (like coronary heart disease and stroke), cancers, type 2 diabetes, and chronic respiratory diseases such as asthma. These diseases are the leading cause of death and disability worldwide, accounting for over 70% of all deaths globally. Understanding NCDs is crucial because they are largely preventable through lifestyle modifications, and their management places a significant burden on healthcare systems.

This topic explores the risk factors associated with NCDs, including genetic predisposition, lifestyle choices (diet, physical activity, smoking, alcohol consumption), and environmental factors. You will learn how these risk factors interact to increase the likelihood of developing specific diseases. For example, a diet high in saturated fats and low in fibre can lead to obesity and high blood pressure, which are major risk factors for cardiovascular disease and type 2 diabetes. The topic also covers the concept of correlation and causation, helping you critically evaluate evidence linking risk factors to disease.

In the WJEC GCSE Biology curriculum, this topic builds on your understanding of the human body systems, particularly the circulatory and respiratory systems, and introduces the idea of disease prevention at a population level. You will also explore how lifestyle choices can affect the function of organs and cells, leading to disease. Mastery of this topic is essential for understanding public health strategies and the importance of personal responsibility in maintaining health.

Key Concepts

Core ideas you must understand for this topic

→Risk factors: Any attribute, characteristic, or exposure that increases the likelihood of developing a disease. These can be non-modifiable (e.g., age, genetics) or modifiable (e.g., diet, smoking, exercise).
→Correlation vs. causation: A correlation between a risk factor and a disease does not prove that the risk factor causes the disease. For example, there is a correlation between ice cream sales and drowning, but ice cream does not cause drowning; both are linked to hot weather.
→Cardiovascular disease: Includes conditions like coronary heart disease (blocked arteries) and stroke. Key risk factors include high blood pressure, high cholesterol, smoking, and lack of exercise.
→Type 2 diabetes: A condition where the body becomes resistant to insulin or does not produce enough insulin. Major risk factors include obesity, poor diet, and physical inactivity.
→Cancer: A disease where cells divide uncontrollably. Risk factors include smoking (lung cancer), UV radiation (skin cancer), and certain viruses (e.g., HPV for cervical cancer).

What You Need to Demonstrate

Key skills and knowledge for this topic

Identification of lifestyle factors causing non-communicable diseases (cardiovascular disease, lung cancer, skin cancer, emphysema, type 2 diabetes, cirrhosis).
Explanation of how lifestyle factors (exercise, diet, alcohol, smoking, UV radiation) influence disease incidence at local, national, and global levels.
Evaluation of treatments for cardiovascular disease including statins, angioplasty, and lifestyle changes (diet/exercise).
Understanding that non-communicable diseases result from the interaction of multiple lifestyle factors.

Marking Points

Key points examiners look for in your answers

Identification of lifestyle factors causing non-communicable diseases (cardiovascular disease, lung cancer, skin cancer, emphysema, type 2 diabetes, cirrhosis).
Explanation of how lifestyle factors (exercise, diet, alcohol, smoking, UV radiation) influence disease incidence at local, national, and global levels.
Evaluation of treatments for cardiovascular disease including statins, angioplasty, and lifestyle changes (diet/exercise).
Understanding that non-communicable diseases result from the interaction of multiple lifestyle factors.

Examiner Tips

Expert advice for maximising your marks

💡Ensure you can explain the 'interaction' of factors, as diseases are rarely caused by a single factor alone.
💡When evaluating treatments, always provide both pros and cons to gain full marks.
💡Use specific terminology when discussing cardiovascular disease treatments like statins and angioplasty.
💡When answering questions about risk factors, always distinguish between correlation and causation. Use examples like 'smoking is correlated with lung cancer, but it is also a cause because it directly damages DNA in lung cells.'
💡For questions on prevention, be specific about lifestyle changes. Instead of saying 'eat healthily,' mention 'reducing saturated fat intake to lower cholesterol' or 'increasing fibre intake to reduce bowel cancer risk.'
💡In data analysis questions, always describe the trend shown in the graph or table, and then suggest a possible biological explanation. For example, 'The graph shows that as BMI increases, the risk of type 2 diabetes increases. This may be because excess body fat leads to insulin resistance.'

Common Mistakes

Pitfalls to avoid in your exam answers

Confusing non-communicable diseases with communicable diseases.
Failing to link specific lifestyle factors to the correct disease.
Providing one-sided evaluations of treatments without considering both advantages and disadvantages.
Misconception: 'If a risk factor is correlated with a disease, it must cause the disease.' Correction: Correlation does not imply causation. Other factors (confounding variables) may be responsible. For example, people who exercise more may also eat healthier, so the exercise itself might not be the sole cause of reduced heart disease risk.
Misconception: 'Non-communicable diseases only affect older people.' Correction: While age is a risk factor, NCDs can affect people of all ages. For instance, type 2 diabetes is increasingly diagnosed in children and young adults due to rising obesity rates.
Misconception: 'Cancer is always caused by inherited genes.' Correction: Only a small percentage of cancers (about 5-10%) are inherited. Most cancers are caused by mutations that occur during a person's lifetime due to environmental and lifestyle factors.

Frequently Asked Questions

Common questions students ask about this topic

Before You Start

Prior knowledge that will help with this topic

•Basic understanding of the circulatory system (heart, blood vessels, blood pressure) and respiratory system (lungs, gas exchange).
•Knowledge of cell division and the concept of mutations (for cancer).
•Familiarity with the concept of homeostasis and the role of insulin in blood glucose regulation (for diabetes).

Study Guide Available

Comprehensive revision notes & examples

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Likely Command Words

How questions on this topic are typically asked

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Explain

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Practice questions tailored to this topic

Non-communicable diseases in humans

Topic Overview

Key Concepts

What You Need to Demonstrate

Marking Points

Examiner Tips

Common Mistakes

Frequently Asked Questions

Before You Start

Study Guide Available

Likely Command Words

Ready to test yourself?

Related Topics in WJEC GCSE Biology

Biodiversity

Cell biology

Cell metabolism

Communicable disease

Topic Synopsis

Key Concepts & Core Principles

Exam Tips & Revision Strategies

Common Misconceptions & Mistakes to Avoid

Examiner Marking Points

Non-communicable diseases in humans

Topic Overview

Key Concepts

What You Need to Demonstrate

Marking Points

Examiner Tips

Common Mistakes

Frequently Asked Questions

What is the difference between a communicable and non-communicable disease?

Can non-communicable diseases be cured?

How does smoking cause non-communicable diseases?

Why is obesity a risk factor for many non-communicable diseases?

What is the difference between type 1 and type 2 diabetes?

How can I reduce my risk of developing cancer?

Before You Start

Study Guide Available

Likely Command Words

Ready to test yourself?

Related Topics in WJEC GCSE Biology

Biodiversity

Cell biology

Cell metabolism

Communicable disease