TUESDAY, Nov. 12 (HealthScoutNews) -- The health disadvantages of using growth hormone to fight the aging process far outweigh any benefit it may carry, new research says.
The study finds older men and women taking human growth hormone and sex hormones can increase muscle, decrease fat and improve aerobic capacity. The bad news, however, is that some of those benefits aren't as great as they seem at first blush. Moreover, the treatment has all sorts of unpleasant or dangerous side effects. They include swelling, arthritis-like joint pain, carpal tunnel syndrome and, most seriously, an increase in glucose intolerance and diabetes.
"Growth hormone intervention in the elderly is not yet ready for prime time," says study author Dr. Marc Blackman, clinical director for the National Center for Complementary and Alternative Medicine at the National Institutes of Health. "These hormones are powerful, and we need to learn much more about them before we use them as an anti-aging treatment."
The study appears in tomorrow's Journal of the American Medical Association, a special issue that focuses on aging.
Blackman and his colleagues divided 74 men and 57 women, aged 65 to 88, into eight groups. Each group was given a different combination of the hormones.
The four women's groups were given growth hormone alone, the sex hormones estrogen and progesterone alone, both growth hormone and estrogen/progesterone, or a placebo.
The four men's groups were given either growth hormone alone, the sex hormone testosterone alone, both growth hormone and testosterone, or a placebo.
The aim for the six-month study was to restore the levels of growth hormone and sex hormones to that of healthy 20- to 35-year-olds, Blackman says. He explained that as people age, they experience a decrease in muscle mass and strength, an increase in body fat, a thinning of the bones, and a decrease in cardiovascular endurance.
Normal aging is also associated with a decrease in the release of testosterone in men, estrogen and progesterone in women, and growth hormone in both sexes.
The hope was that restoring levels of these key hormones in elderly people would reverse some of the signs of aging, Blackman says.
It didn't work out quite that well.
Men and women treated with growth hormone alone or a growth hormone/sex hormone combo showed a significant increase in lean body mass and a decrease in fat. The groups treated with only the sex hormones or the placebo showed no increase.
However, while muscle mass increased, their strength didn't. That could mean the cells in the lean body tissues were simply more full of water, making it appear bigger on a measuring device called a dual-energy X-ray absorptiometry, says Dr. Richard Spark, director of steroid research at Beth Israel Hospital and associate clinical professor of medicine at Harvard Medical School in Boston.
"What it basically says is you can change the architecture of the body without improving the function of the body," Spark says. "That has bedeviled human growth hormone advocates for years."
The study also found that men who were given growth hormone and testosterone showed an increase in aerobic capacity during a treadmill test. Women didn't show similar gains.
However, the major problem with the hormone treatment is the side effects -- 40 percent of men and women in the study experienced swelling, joint pain and glucose intolerance or diabetes.
"The side effects of human growth hormone are substantial," Spark says. "Its a fairly toxic treatment."
The side effects went away a few weeks after the hormone treatment was halted.
Growth hormone is produced in the pituitary gland. It's common practice to give growth hormone supplements to someone who has a growth hormone deficiency because of disease, such as a pituitary tumor, Spark says.
The same goes for testosterone. Men who have a testosterone deficiency are often prescribed hormone replacement.
But recently, more men with what doctors consider normal hormone levels for their age have been requesting supplements as an anti-aging treatment, which worries doctors.
"I couldn't possibly sanction giving it to them until I know they're effective and safe," Blackman says. "And at this point we still have a lot more to learn."