Non-communicable diseases, nutrition and lifestyle risk factors
Scope
The domain tests the epidemiology and prevention of non-communicable diseases, nutrition standards and the interpretation of anthropometric and lifestyle risk.
Core rules
- The four main NCD groups are cardiovascular disease, cancer, diabetes and chronic respiratory disease. The four shared behavioural risks are tobacco, harmful alcohol use, unhealthy diet and physical inactivity.
- WHO best buys include tobacco taxation, smoke-free spaces, alcohol pricing and availability limits, salt reduction, trans-fat elimination, and promotion of healthy diets and activity.
- BMI is weight in kilograms divided by height in metres squared. Adults: underweight below 18.5, normal 18.5–24.9, overweight 25–29.9, obesity 30 or above. Waist circumference above 94 cm in men and 80 cm in women signals central obesity; above 102 cm and 88 cm respectively signals substantially increased risk.
- Dietary targets: salt under 5 g/day, free sugars under 10% of energy (ideally under 5%), saturated fat under 10%, trans fat under 1%, fruit and vegetables at least 400 g/day, fibre 25–30 g/day.
- Physical activity: 150–300 minutes of moderate or 75–150 minutes of vigorous activity weekly, plus muscle strengthening twice weekly. There is no safe threshold for alcohol; risk rises with dose.
- Screening programmes follow EU Council recommendations: breast (50–69, biennial), cervical (25–64) and colorectal (50–74).
Worked example
A man is 1.78 m tall and weighs 89 kg. BMI = 89/(1.78²) = 89/3.168 ≈ 28.1, which is overweight. Waist 103 cm indicates central obesity and substantially increased cardiometabolic risk. The reasoning: BMI alone misses fat distribution and muscle mass, so waist circumference refines risk. The plan prioritises cessation, a 5–10% weight loss, 150 minutes of activity weekly and a dietary pattern low in salt and free sugars, with blood pressure and HbA1c checked.
Traps
Do not use BMI cut-offs for children or athletes without adjustment; do not state that moderate alcohol is cardioprotective; do not confuse overweight and obesity thresholds; do not present screening as prevention of disease onset.