Monday, October 15th, 2012
Teenaged boys who are obese have testosterone levels that are lower than normal-weight teens, to the point of being “alarming,” researchers have found in a new study published in the journal Clinical Endocrinology. The research may offer a clue into at least one medical explanation for obesity in boys. CNN has more:
“It has its origins in earlier research, which showed that type II diabetes and obesity in older men are linked to a high rate (25-33%) of hypogonadism, or low testosterone levels. According to the new study, the rate of hypogonadism in type II diabetic men ages 18-35 is greater than 50%.
In addition, concentrations of free testosterone — testosterone that isn’t chemically bound and thus available to the body — were shown to be negatively related to BMI: The higher the body mass, the lower the concentration.
“This raises the question whether obesity is associated with lower testosterone concentrations, even in younger males,” the study said.
Controlling for age, physical maturity and certain medical factors, 25 obese and 25 lean males between the ages of 14 and 20 were studied.
Blood samples were drawn in the morning to measure both total and free testosterone.
Mean testosterone concentration was 50% lower in obese males. Mean free testosterone concentration was 46% lower.
The results present several problems for those affected, according to Dr. Paresh Dandona, chief of the Division of Endocrinology, Diabetes and Metabolism at the University of Buffalo’s medical school and the study’s lead author.
Obesity can lead to diabetes and heart disease. What’s more, low testosterone can slow or stop sexual maturation — and there’s nothing more hurtful than “a male not having his maleness,” Dandona said.”
Image: Obese boy, via Shutterstock
Tuesday, September 13th, 2011
The first longitudinal study of testosterone levels in fathers has found that the longer a man has been a father–and the more involved with the daily care of his children he is–the lower his testosterone level drops.
The study measured testosterone levels in 21-year-old men before they became fathers, and then again 5 years later. Those who became fathers had more than double the drop in testosterone than non-fathers (all men experience a drop in testosterone as they age). And those men who spent more than three hours caring for their children each day had the lowest level of all.
The New York Times reports on the study, which was published in the journal Proceedings of the National Academy of Sciences:
“The real take-home message,” said Peter Ellison, a professor of human evolutionary biology at Harvard who was not involved in the study, is that “male parental care is important. It’s important enough that it’s actually shaped the physiology of men.”
“Unfortunately,” Dr. Ellison added, “I think American males have been brainwashed” to believe lower testosterone means that “maybe you’re a wimp, that it’s because you’re not really a man.
“My hope would be that this kind of research has an impact on the American male. It would make them realize that we’re meant to be active fathers and participate in the care of our offspring.”
The study, experts say, suggests that men’s bodies evolved hormonal systems that helped them commit to their families once children were born. It also suggests that men’s behavior can affect hormonal signals their bodies send, not just that hormones influence behavior. And, experts say, it underscores that mothers were meant to have child care help.
“This is part of the guy being invested in the marriage,” said Carol Worthman, an anthropologist at Emory University who also was not involved in the study. Lower testosterone, she said, is the father’s way of saying, “ ‘I’m here, I’m not looking around, I’m really toning things down so I can have good relationships.’ What’s great about this study is it lays it on the table that more is not always better. Faster, bigger, stronger — no, not always.”
(image via: http://www.hfihouston.org)