Explain the effect of lifestyle factors on non-communicable diseases at…

The idea

Non-communicable diseases cannot be passed between people, and lifestyle choices change their risk. Too little exercise with an energy-rich diet tends to store excess energy as fat, raising obesity risk; too little food or an unbalanced diet causes malnutrition. BMI compares mass with height: BMI = mass (kg) ÷ height² (m²), so a 70 kg person of height 1.75 m has BMI = 70 ÷ 3.0625 ≈ 22.9 kg/m². Waist : hip ratio compares waist circumference with hip circumference and indicates fat distribution. Alcohol consumption damages liver cells and is linked to liver disease such as cirrhosis. Smoking damages blood vessels and raises blood pressure, increasing cardiovascular disease risk. These effects appear in individuals locally, in whole populations nationally and worldwide.

What earns the marks

• Calculates BMI by dividing mass in kilograms by the square of height in metres, giving units of kg/m².
• Identifies that regular exercise combined with a balanced diet lowers obesity risk by using up energy intake.
• Recognises that malnutrition results from an inadequate or unbalanced diet rather than from infection.
• States that alcohol consumption is linked to liver disease such as cirrhosis.
• Explains that smoking damages blood vessels and raises blood pressure, increasing cardiovascular disease risk.
• Describes how a lifestyle factor affects disease risk at local, national and global scales.

Common mistakes and how to put them right

• Squares the height after dividing instead of dividing mass by height squared.

  Put it right: Divide mass by height² first.

• Uses height in centimetres in the BMI equation.

  Put it right: Convert height to metres before squaring.

• Treats non-communicable diseases as spread by pathogens between people.

  Put it right: Describe them as conditions linked to lifestyle and other factors.

Exam tips

• Write the BMI equation, substitute values with units, then give the answer to one or two decimal places with kg/m².
• Link each named lifestyle factor to the specific disease group in the statement rather than a general 'bad health' answer.
• Use the words local, national and global when asked about scale, giving one brief example for each.
• Check whether the question asks for a calculation or an explanation, and answer only what is asked.