Overweight teenagers run the same risk of an early death as people who smoke regularly – and the risk increases substantially with very fat adolescents.
Teenagers who are clinically obese have the same risk of premature death as someone who smokes more than 10 cigarettes a day. An investigation of 45,000 men whose health was monitored for 38 years has found that being overweight at the age of 18 is equivalent to being a regular smoker in terms of the overall risk of dying relatively early in life from preventable diseases.
Men who both smoked and were overweight as teenagers were likely to die even earlier than those who fell into just one or other of the risk groups. But the study did not find any evidence to suggest that smoking and obesity combined to produce even greater risks when found together.
Martin Neovius of the Karolinksa Institute in Stockholm, who carried out the study published in the British Medical Journal, said: "It shows the importance of measures to reduce obesity in adolescents. A lot of people are dying from preventable deaths.
"I think we should be looking at what we can learn from the anti-tobacco campaign in terms of obesity. There are some who argue that being overweight – but not clinically obese – is harmless. No, it is not harmless because we found that a being an overweight adolescent is equivalent to smoking up to 10 cigarettes a day."
Overweight is defined as having a body mass index – a measure of body fat based on height and weight – of between 25 and 30, whereas being obese is defined as having a BMI of more than 30. Being overweight at 18 increased the risk of an early death by just more than a third, while being obese more than doubled the risk. The risk of premature death also increased with the number of cigarettes smoked, with heavy smokers at more than double the risk of dying relatively early in life compared to non-smokers.
The study also found that men who were seriously underweight at 18 also had a higher risk of a premature death and this risk also increased with the number of cigarettes they smoked.