Health and non-communicable disease · Year 11
Health is a state of physical and mental well-being. Diseases are a major cause of ill health. Communicable diseases are caused by pathogens and can spread; non-communicable diseases, such as heart disease, most cancers and Type 2 diabetes, cannot. Many of them are linked to risk factors in the way we live.
Key facts
- Communicable diseases are caused by pathogens and can be passed on. Non-communicable diseases are not caused by pathogens and cannot be passed from person to person.
- A risk factor makes a disease more likely: smoking (lung disease, lung cancer, heart disease), obesity and too little exercise (Type 2 diabetes, heart disease), alcohol (liver disease), ultraviolet light and other carcinogens (cancer).
- A correlation between a risk factor and a disease does not on its own prove cause. Scientists look for a mechanism, such as chemicals in tobacco smoke damaging DNA.
- Cancer is the result of changes in cells that lead to uncontrolled growth and division. Benign tumours stay in one place; malignant tumours are cancers that invade tissues and spread in the blood to form secondary tumours.
- In coronary heart disease, layers of fatty material build up inside the coronary arteries, so less oxygen reaches the heart muscle. Treatments: stents keep arteries open, statins lower blood cholesterol, and failing hearts or valves can be replaced.
- Diseases interact: a weak immune system makes infection more likely, some viruses trigger cancers, and ill health can affect mental health.
- Health data: percentage = part ÷ whole × 100; rate per 100,000 = cases ÷ population × 100,000; BMI = mass (kg) ÷ height² (m²).