HOUSTON — Men with low testosterone who are given replacement doses of the hormone shed weight steadily for years, researchers in Germany reported June 23 at a meeting of the Endocrine Society. Study participants, nearly all of whom were overweight or obese at the start of the study, lost 36 pounds on average.
“This was an unintended effect,” said study coauthor Farid Saad, a research endocrinologist at Bayer Pharma in Berlin. “The big surprise was that when we analyzed the data [we found] that these men had lost weight continuously…year by year.” The men didn’t diet as part of the study, and any increase in their activity was voluntary, Saad said.
He and his colleagues studied 116 men, average age 61, who had low testosterone levels. Each received quarterly injections of the hormone for five years. At the start, 71 percent were obese and another 24 percent were overweight.
After five years, 97 percent of the men showed a reduction in waist circumference, on average losing “three to four trouser sizes,” Saad said. Average weight dropped from 236 pounds to about 200.
“This definitely offers some insight that we can apply to our clinical practices,” said Vineeth Mohan, a clinical endocrinologist at Cleveland Clinic Florida in Weston.
High testosterone levels have been linked to prostate cancer risk (SN: 10/8/05, p. 238), and a small portion of men taking high doses of it experience mania (SN: 2/19/00, p. 119). But in this study, Saad said, men received testosterone in doses just high enough to bring them back to normal levels. Three men in the test group were diagnosed with prostate cancer during the study, a rate lower than the incidence found in routine screening programs for men that age, he said.
Fat tissue induces the release of cortisone and other chemicals that studies have shown suppress production of testosterone, Saad said. The result is depressed mood, low energy and less activity. “This is a vicious circle that leads to more accumulation of fat mass and [continued] low levels of testosterone,” he said.
This loss is not greatly governed by age. An Australian study also reported at the meeting linked testosterone decline more closely to obesity, diabetes and depression than aging. Study coauthor Gary Wittert, a clinical endocrinologist of the University of Adelaide, reported that age had only a slight effect on testosterone levels in 1,384 men studied over five years, whereas depression had an effect two to three times as great.That and other data suggest that “testosterone decline is not an inevitable result of aging among men,” Wittert said. Rather, loss is attributable to “a variety of factors such as social demographics, health status, chronic disease, obesity and depression.”