<p class="first" id="P1">Levels of insulin-like growth factor (IGF)-1, IGF binding
protein (IGFBP)-3, and their
ratio in the blood may be useful for monitoring those at risk of cognitive and functional
decline. However, the association between IGF measures and functional and cognitive
outcomes has been mixed, and the associations may vary by sex. The present study investigated
the cross-sectional, sex-specific associations between serum measures total IGF-1,
IGFBP-3, and the IGF-1/IGFBP-3 ratio, gait speed, and cognition in 1,320 cognitively
unimpaired participants aged 50-95 enrolled in the Mayo Clinic Study of Aging. We
utilized multivariable linear regression models to determine the association between
IGF measures and gait speed or cognitive test performance by sex. IGF measures were
not associated with cognitive or functional performance among men. Among women, higher
levels of log total IGF-1 and IGFBP-3 were associated with better performance in attention,
visuospatial, and global cognitive domains, independent of gait speed. These findings
suggest that among women IGF measures are associated with cognition, and these associations
are independent of function.
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