A recent study finds obese teenage boys have 50 % reduced testosterone and that they will face an increasing risk of infertility in later life.

An alarming recent study by researchers at the University at Buffalo in New York and published in the journal Clinical Endocrinology, found that obese teenage boys have up to 50 per cent less testosterone than their peers of normal weight and that they will face an increasing risk of infertility in later life. The researchers called their findings a “grim message” for overweight young adults. The same researchers reported in 2004 the presence of low testosterone levels called hypogonadism in obese, type 2 diabetic adult males and later confirmed the condition in 2010 in more than 2,000 obese men, both diabetic and non-diabetic.

The latest study shows for the first time that obese young men aged 14 to 20 have about half the total testosterone than normal weight kids of the same age. The Buffalo study’s lead author Dr Paresh Dandona, said: 'We were surprised to observe a 50 per cent reduction in testosterone in this pediatric study because these obese males were young and were not diabetic. The implications of our findings are, frankly, horrendous because these boys are potentially impotent and infertile. The message is a grim one with massive epidemiological implications.”
 
The Buffalo study included 25 obese and 25 lean boys and was controlled for age and level of sexual maturity. The researchers looked for concentrations of total and free testosterone and estradiol, an oestrogen hormone that were measured in blood samples. The findings demonstrated that lifestyle and nutritional intake starting in childhood can have major impacts throughout all stages of life. The researchers said that in addition to the reproductive impacts, low levels of testosterone will also increase abdominal fat and reduce muscle mass, both conditions leading to greater insulin resistance and contributing to the onset of diabetes. The only bright spot in the entire study was that similar to the effects of gastric bypass surgery where testosterone levels return to normal, the researchers will perform more studies to determine if weight loss through lifestyle changes or drug therapy will be able to restore the testosterone levels in obese teenage boys.