Declining Testosterone Not Normal Part of Aging
It's commonly accepted that men experience a drop in testosterone as they age, but there's little scientific evidence that identifies the true cause. Now, a population-based study of 1,500 men has shown researchers at the University of Adelaide in Australia that the drop in hormones isn't necessarily destined to hit all aging males.
"Declining testosterone levels are not an inevitable part of the aging process, as many people think," said study co-author Gary Wittert. He and his colleagues analyzed testosterone measurements from clinic visits taken five years apart for each of the participating men.
Like Us on Facebook
The study found, on average, testosterone levels did not decline significantly over five years; rather, they decreased less than 1 percent each year, reports UPI. When the researchers excluded men who were taking medications or had medical conditions known to affect hormones - 1,382 men aged 35 to 80 years were included in the analysis - they found several factors linked to declining testosterone.
"Men who had declines in testosterone were more likely to be those who became obese, had stopped smoking or were depressed at either clinic visit," Witter said. "While stopping smoking may be a cause of a slight decrease in testosterone, the benefit of quitting smoking is huge."
Unmarried men in the study were also found to have greater testosterone reductions than married men. Wittert said past research has shown that marreid men tend to be healthier and happier than unmarreid men. "Also, regular sexual activity tends to increase testosterone," he said.
The study is being presented at The Endocrine Society's Annual Meeting, where another study on testosterone levels may give credence to the finding that weight can affect an aging man's hormones.
Frances Hayes, a professor at St. Vincent's University Hospital in Dublin, led a study involving nearly 900 prediabetic men to test the effect of weight loss on men's testosterone levels, reports Science Daily. Like Wittert's study, the men had an average age of 54, though all participants were at high risk for Type 2 diabetes. Low testosterone is common in overweight men with prediabetes, Hayes said, and at the beginning of the study, nearly 1 in 4 participants had low hormone levels.
The men were randomly assigned to receive one of three treatments: 293 men to lifestyle modification, 305 to the diabetes drug metformin and 293 to inactive placebo pills. Lifestyle modifications consisted of exercising for 150 minutes a week and eating less fat and fewer calories.
The results showed that weight loss can reduce the prevalence of low testosterone levels in overweight, middle-aged men with prediabetes by almost 50 percent in just one year. The prevalence of low testosterone was unchanged in the other two groups.
"Doctors should first encourage overweight men with low testosterone levels to try to lose weight through diet and exercise before resorting to testosterone therapy to raise their hormone levels," Hayes said.
© 2012 iScience Times All rights reserved. Do not reproduce without permission.