The effect of lifestyle on some non-communicable diseases: substances in the person’s body or environment.

The idea

Risk of non-communicable disease also depends on factors inside the body or present in the environment. Inside the body, these include inherited factors such as faulty genes, hormones and chemicals produced by the body. In the environment, they include air pollutants such as particulates from burning fuels, carcinogens such as asbestos or tobacco smoke, and ionising radiation such as X-rays or gamma rays. Ultraviolet light from the Sun is non-ionising radiation, but it can still damage DNA in skin cells and increase melanoma risk. Air pollution can worsen cardiovascular and respiratory disease. Scientists use population studies to estimate how strongly each factor raises risk, because individuals vary in exposure and susceptibility.

What earns the marks

• Identify factors inside the body, such as inherited faulty genes, hormones or body chemicals, that affect disease risk.
• Identify environmental factors, such as air pollutants, carcinogens or ionising radiation, that affect disease risk.
• Link a named factor to a named non-communicable disease, for example ultraviolet radiation to skin cancer or tobacco smoke to lung cancer.
• Explain that exposure level and duration affect the size of the risk, for example more smoking or more Sun exposure raises risk.
• Recognise that body and environmental factors interact with lifestyle factors rather than acting in isolation.
• Distinguish ionising radiation (for example X-rays and gamma rays) from non-ionising ultraviolet light, while noting that both can damage DNA.

Common mistakes and how to put them right

• Calling genes a lifestyle factor.

  Put it right: Inherited genes are inside the body and are not chosen habits.

• Saying a factor definitely causes disease.

  Put it right: Describe it as increasing risk, since not everyone exposed develops the disease.

• Describing ultraviolet light as ionising radiation.

  Put it right: UV is non-ionising, whereas X-rays and gamma rays are ionising.

• Ignoring dose: state that greater exposure or longer exposure usually means greater risk.

Exam tips

• Separate your answer into factors inside the body and environmental factors to cover both parts of the statement.
• Use precise names such as ultraviolet radiation, particulates or carcinogens instead of vague words like pollution.
• When data is given, quote a figure and compare risk between exposed and unexposed groups.
• If asked about radiation, state whether it is ionising or non-ionising and give an example of each.