Table of Contents
ISRN Endocrinology
Volume 2011 (2011), Article ID 249421, 6 pages
http://dx.doi.org/10.5402/2011/249421
Research Article

The GH/IGF-I Axis and Cognitive Changes across a 4-Year Period in Healthy Adults

1Department of Clinical Neuropsychology, VU University of Amsterdam, van der Boechorst Street 1, 1081 BT Amsterdam, The Netherlands
2Section Endocrinology, Department of Internal Medicine, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands

Received 4 January 2011; Accepted 15 February 2011

Academic Editors: L. Frago, K. Hull, and C. M. Perks

Copyright © 2011 Jan Berend Deijen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

After the age of 40, the amount of growth hormone in humans decreases. The reduced activity of the GH-IGF axis may play a role in age-related cognitive impairments. In the present study, mood and cognition of 30 healthy subjects (7 males, 23 females, aged 41–76 yr, mean age 6 0 . 9 Β± 9 . 0 ) were examined twice. At baseline, we determined fasting blood levels of GH and IGF-I. Mood and cognitive status were assessed at baseline and after, on the average, 3 years and 9 months of followup. Working memory performance decreased over the years in the low IGF-group ( 𝑃 = . 0 0 7 ), but not the high IGF-I group. Higher levels of GH were related with a better working memory at the second test ( π‘Ÿ = 0 . 4 2 , 𝑃 = . 0 1 ) while higher levels of IGF-I tended to be related with a better working memory ( π‘Ÿ = 0 . 3 , 𝑃 = . 0 6 ). The results suggest that higher serum levels of GH and IGF-I preserve the quality of working memory functions over the years.