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Updated: Aug 6, 2026
Assessment of Age-related Changes in Cognitive Functions Using EmoCogMeter, a Novel Tablet-computer Based Approach
Published on: February 14, 2014
Midlife plasma insulin-like growth factor I and cognitive function in older men
Olivia I Okereke1, Jae H Kang, Jing Ma
1Division of Aging, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA. ookereke@partners.org
Context:
Emerging biological and epidemiological evidence suggests possible benefits of higher IGF-I levels in cognitive aging.
Objective:
The objective of the study was to examine the relation of midlife plasma IGF-I levels to late-life cognition.
Design, Setting, And Participants:
We conducted a secondary analysis from the Physicians' Health Study II, a prospective cohort of U.S. male physicians. Participants provided blood samples from 1982 to 1984 (mean age 57 yr). Using stored samples, we measured free IGF-I in 376 men and total IGF-I and IGF binding protein-3 in 460 men. Starting in 2001, we administered telephone-based tests of general cognition [the Telephone Interview of Cognitive Status (TICS)], verbal memory, and category fluency. We estimated multivariable-adjusted mean differences in cognitive performance across levels of free IGF-I and IGF-I to IGF binding protein-3 molar ratio.
Main Outcome Measures:
Global score (averaging performance across all individual cognitive tests), the TICS, and a verbal memory score were measured.
Results:
Each sd increment in free IGF-I was associated with a multivariable-adjusted increase of 0.08 U (P = 0.02) on the global score. This mean difference was equivalent to that observed between men 2 yr apart in age: i.e. each sd increase in free IGF-I appeared cognitively equivalent to staying 2 yr younger. No significant mean differences in TICS scores were observed across free IGF-I levels. For verbal memory, each sd increment in free IGF-I was associated with an adjusted mean difference of 0.08 U (P = 0.03). Results appeared consistent for the molar ratio but were not statistically significant.
Conclusion:
Higher midlife free IGF-I may be associated with better late-life cognition.
