(Ivanhoe Newswire) -- Older men with high levels of the hormone IGF-I
(insulin-like growth factor 1) are at increased risk of cancer death that is
independent of age, lifestyle and cancer history.
IGF-I is a protein hormone similar in structure to insulin and is regulated in
the body by growth hormone (GH). Levels of GH and IGF-I decline progressively
with age in both men and women, and this drop is thought to be related to
deteriorating health conditions found with advancing age. In an attempt to
combat aging some people use GH as its actions elevate IGF-1.The current study,
however, showed that older men who had higher IGF-I levels were more likely to
die from a cancer-related cause in the ensuing 18 years than men with lower
levels.
"This is the first population-based study to show an association of higher IGF-I
levels with increased risk of a cancer-related death in older men,"
corresponding author Gail Laughlin, Ph.D., of the University of California San
Diego, was quoted as saying. "Although the design of this study does not
explicitly show that the higher IGF-I levels caused the cancer death, it does
encourage more study as well as a reexamination of the use of IGF-I enhancing
therapies as an anti-aging strategy."
Researchers used data on 633 men aged 50 and older from the Rancho Bernardo
Study, a population-based study of healthy aging. Study participants took part
in a research clinic examination between the 1988 and 1991, when their blood was
analyzed and IGF-I was measured. Participants were followed through July 2006.
Researchers found men who had IGF-I levels above 100 ng/ml had almost twice the
risk of cancer death in the following 18 years as men with lower levels.
"In this study, the increased risk of cancer death for older men with high
levels of IGF-I was not explained by differences in age, body size, lifestyle or
cancer history," lead author Jacqueline Major, Ph.D., at the National Cancer
Institute, was quoted as saying. "If these results are confirmed in other
populations, these findings suggest that serum IGF-I may have potential
importance as a biomarker for prognostic testing."
SOURCE: Journal of Clinical Endocrinology & Metabolism (JCEM), March 1, 2010
