Posted by Phillipa on June 17, 2009, at 20:33:26
Not quite sure what the implications for this study are. Anyone see the real meaning? Phillipa
From Reuters Health Information
Subclinical Hypothyroidism May Contribute to Healthy Aging
NEW YORK (Reuters Health) Jun 15 - The population shift in thyroid-stimulating hormone (TSH) to higher levels that occurs with aging may have a genetic basis and may contribute to healthy aging, according to research presented at The Endocrine Society's 91st Annual meeting in Washington, DC."Our data suggest that levothyroxine treatment of the elderly for elevated TSH alone, but not true hypothyroidism, could be harmful," Dr. Martin Surks of Albert Einstein College of Medicine, Bronx, New York, and colleagues conclude.
The investigators studied a well-defined population of 236 Ashkenazi Jewish centenarians, 434 of their children (median age 67 years), and 188 spouses of the children, which served as age-matched but not genetically matched controls.
Median TSH levels were significantly higher in the centenarians than in their offspring and, "importantly," Dr. Surks told the conference, "those of the offspring were higher than in their spouses of the same age. This suggests a genetic predisposition for higher TSH in the centenarians and in their children."
A heritability analysis showed a significant degree of heritability in TSH between the children and their parents, again suggesting a genetic basis for the findings.
Genetic analysis revealed two distinct single nucleotide polymorphisms in the TSH receptor that were associated with an increase in TSH. "The prevalence of these variants was very much higher in the centenarians and their offspring than in the controls, and those that had these receptor variants had higher TSH than those who did not," Dr. Surks noted.
Taken together, these findings show a likely genetic basis for the increase in TSH in this Ashkenazi Jewish centenarian population as well as their children.
The findings also suggest that the increase in TSH "may be protective and possibly contribute to healthy aging," Dr. Surks noted. This hypothesis, he noted, is supported by animal studies, which have demonstrated that animals with decreased thyroid function have extended life spans.
"If our findings are extended to other human populations -- and these studies are in progress -- the current designation of subclinical hypothyroidism in elderly people as an illness than needs treatment should be changed," Dr. Surks said.
"If the raised TSH is good for healthy aging and longevity treatment with thyroid hormones would clearly not be necessary," he concluded.
poster:Phillipa
thread:901616
URL: http://www.dr-bob.org/babble/20090611/msgs/901616.html