deficiency and cognitive impairment are common in older adults, but there isn’t
a lot of conclusive research into whether there’s a relationship between the
new study from Wake Forest Baptist Medical Center published online ahead of print this month
in the journal of the American Geriatrics Society enhances the existing
literature on the subject.
study provides increasing evidence that suggests there is an association
between low vitamin D levels and cognitive decline over time,” said lead author
Valerie Wilson, M.D., assistant professor of geriatrics at Wake Forest Baptist.
“Although this study cannot establish a direct cause and effect relationship,
it would have a
huge public health implication if vitamin D supplementation could be shown to
improve cognitive performance over time because deficiency is so common in the
and colleagues were interested in the association between vitamin D levels and
cognitive function over time in older adults. They used data from the Health,
Aging and Body composition (Health ABC) study to look at the relationship. The
researchers looked at 2,777 well-functioning adults aged 70 to 79 whose cognitive
function was measured at the study’s onset and again four years later. Vitamin
D levels were measured at the 12-month follow-up visit.
Health ABC study cohort consists of 3,075 Medicare-eligible, white and black,
well-functioning, community-dwelling older adults who were recruited between
April 1997 and June 1998 from Pittsburgh, Pa., and Memphis, Tenn.
“With just the baseline
observational data, you can’t conclude that low vitamin D causes cognitive
decline. When we looked four years down
the road, low vitamin D was associated with worse cognitive performance on one
of the two cognitive tests used,” Wilson said. “It is interesting that there is
this association and ultimately the next question is whether or not
supplementing vitamin D would improve cognitive function over time.”
Wilson said randomized,
controlled trials are needed to
determine whether vitamin D supplementation can prevent cognitive decline and
definitively establish a causal relationship.
need this information to make well-supported recommendations to their
patients,” Wilson said. “Further research is also needed to evaluate whether
specific cognitive domains, such as memory versus concentration, are especially
sensitive to low vitamin D levels.”
The research is supported in
part by the Intramural Research Program of the National Institutes of Health,
National Institute on Aging and
NIA Contracts N01-AG-6–2101, N01-AG-6–2103, and N01-AG-6–2106; NIA Grants R01
AG028050 and R01 AG029364; and National Institute of Nursing Research Grant R01
included Laurel Kilpatrick, M.D., University of Alabama at Birmingham; Kristine
Yaffe, M.D., and Hilsa N. Ayonayon, Ph.D., both of University of California at
San Francisco,;Jane A. Cauley, Dr.PH., University of Pittsburgh; Tamara
B. Harris, M.D., M.S., and Eleanor M. Simonsick, Ph.D., both of the NIA; and
James Lovato, M.S., Stephen B. Kritchevsky, Ph.D., Denise K.
Houston, Ph.D., and Kaycee M. Sink, M.D., MAS, all of Wake Forest Baptist.