Human Growth Hormone No Fountain Of Youth

STANFORD, Calif. Jan. 15 -- The fact that Ponce de Leon grew old and died should have been an object lesson, but the search goes on for the fountain of youth. Take human growth hormone, a recent popular and expensive candidate. No way, say investigators here.

What's more, there's a good chance it will cause harm, including swollen joints and carpal tunnel syndrome. That's the conclusion of a systematic review of published literature conducted by researchers at Stanford University here.

"There is certainly no data out there to suggest that giving growth hormone to an otherwise healthy person will make him or her live longer," according to Hau Liu, M.D., the lead author of the review, published in the Jan. 16 issue of Annals of Internal Medicine.

"We did find, however, that there was substantial potential for adverse side effects," Dr. Liu added.

The researchers examined randomized, controlled trials that either compared growth hormone therapy with no therapy or growth hormone and lifestyle interventions with lifestyle interventions alone. They excluded studies that evaluated growth hormone as treatment for specific illnesses.

All told, they found 18 distinct study populations, including 220 participants who completed their respective trials, Dr. Liu and colleagues reported. Participants were mainly elderly and overweight, though not obese, and the average duration of therapy was about half a year.

Analysis found that growth hormone:

• Decreased overall fat mass by 2.1 kg on average.
• Increased overall lean body mass by the same amount - a change that was statistically significant at P<0.001 - but did not affect overall weight.
• Decreased total cholesterol levels, although the change was not significant after adjustment for body composition changes.
• Significantly increased the risk of soft tissue edema, arthralgias, carpal tunnel syndrome, and gynecomastia. The risks were significant at P<0.001 for the first three and P<0.05 for gynecomastia.
• Showed a trend toward the onset of diabetes mellitus and impaired fasting glucose.

The conclusion, the researchers said, is that growth hormone in otherwise healthy older people "is associated with small changes in body composition" but no alteration in clinically relevant outcomes, such as bone density, cholesterol and lipids, and maximal oxygen consumption.

"From our review, there's no data to suggest that growth hormone prolongs life, and none of the studies makes that claim," Dr. Liu said.

The use of growth hormone to retard aging has skyrocketed in the U.S. on the past decade, the researchers said, although such use is not approved by the FDA.

According to a 2005 study in the Journal of the American Medical Association, from 20,000 to 30,000 people in the United States used growth hormone as an anti-aging therapy in 2004, at costs ranging as high as ,000 a month.

"You're paying a lot of money for a therapy that may have minimal or no benefit and yet has a potential for some serious side effects," Dr. Liu said. "You've got to really think about what this drug is doing for you."

The researchers were supported by grants from the Agency for Healthcare Research and Quality, the Department of Veterans Affairs, the National Institute of Aging, and Genentech, Inc. One of the authors, Andrew Hoffman, M.D., of Stanford, reported potential conflicts of interest because of having consulted for Genentech, Teva and LG Life Sciences; receiving honoraria from Genentech; and having stock ownership or options in Ambryx.