Obese or overweight boys at 18 carry an elevated risk of cancer. Among the cancers, the risk of lung cancer was found to be high with teenage obesity.
Boys with a high BMI at 18 years carried a 50% risk of dying from lung cancer than the boys who were in the normal weight category.
The risk of cancer of the skin, kidney, bladder, and prostate increased considerably for overweight boys.
Dr Linsay Gray said: "The message is clear - keeping weight healthy as a young adult can reduce your chance of developing cancer."