A tablet that stimulates the production of growth hormone may help older adults improve their physical functioning and lower their body fat percentage, a researcher said yesterday.

But Dr. George Merriam, a professor of medicine at the University of Washington, cautioned that much more study is needed to determine whether the medication should become widely available to help counteract the effects of aging.

Dr. Merriam, who also is associated with the VA Puget Sound Health Care System, led a study whose findings were reported yesterday at the Sixth International Congress of Neuroendocrinology. The four-day conference, which began Monday, is being held at the David L. Lawrence Convention Center, Downtown.

The government has approved use of growth hormone for a limited array of conditions in adults and children, Dr. Merriam said. But it is also used by athletes seeking to enhance their performance and prescribed by anti-aging clinics.

Using growth hormone for non-approved purposes is controversial, he said, and some question whether doctors should try to intervene in the aging process.

But "the line between disease and the disability baggage that accompanies aging is sort of arbitrary," he said, pointing out that many interventions, such as prescribing glasses, have been developed to counteract the effects of aging.

The study he led randomly assigned 395 men and women ages 65 to 84 with mild functional limitations to receive either sugar pills or various oral doses of the growth hormone stimulator capromorelin, an investigational medication developed by Pfizer Global Research and Development.

Compared to placebo, the medication stimulated growth hormone secretion and was associated with an increase in lean muscle mass, improved balance as demonstrated by heel-to-toe walking, and a better ability to climb stairs.

The study did not examine whether the medication improved cognitive functioning.

Other researchers involved in the study were affiliated with Duke University, Stanford University, the University of Arkansas, Johns Hopkins University, the Veterans Affairs health care system, and Pfizer, which supported the project.

Dr. Merriam said Merck and other companies also are investigating similar treatments.

While he called his study's findings encouraging, Dr. Merriam declined to characterize them as a breakthrough, saying more work is needed to determine both the safety and the benefits of the treatment.

"There are no short-term fixes," he said, saying diet and exercise remain preferred approaches to avoiding many health problems associated with aging.

Another researcher who presented a different study at the conference also emphasized the importance of staying active and maintaining a proper diet.

Dr. Agnieszka Baranowska-Bik and colleagues in Warsaw, Poland, examined blood plasma concentrations of adiponectin, a peptide that has anti-inflammatory properties and helps keep vessels clear of fatty deposits, in four groups of women, including 25 aged 100 to 102. They found that the oldest group examined had significantly higher concentrations of adiponectin compared to the other groups.

She said adiponectin could play an important role in longevity and noted that higher levels could be associated with good diet and exercise.

Still another study discussed yesterday involving 1,500 college students concluded that those who experienced early puberty were more likely to engage in abnormal eating behaviors and have feelings of anxiety in early adulthood.

Dr. Julia Zehr, a Michigan State University researcher who led the study, said the findings suggest that biological factors may influence those behaviors, not just the psychological effect of changes in body composition during puberty.