Calcium level may signal risk of mental decline

Calcium level may signal risk of mental decline
NEW YORK (Reuters Health) - In elderly people, higherlevels of calcium in the blood are associated with poorermental function and faster decline in cognitive ability, Dutchresearchers have shown.
Some diseases that increase blood calcium -- such as kidneyfailure, cancer and excessive parathyroid gland activity --could be a factor in the relationship, although it's alsopossible that an individual's calcium "set point" plays a rolein cognitive decline with age, note Dr. Miranda D. Schram andcolleagues in the Journal of the American Geriatrics Society.
Several studies have shown that small but long-termelevations of calcium within nerves and brain cells can killthem, Schram of Leiden University Medical Center and her teampoint out. Calcium can pass from the blood stream into thebrain, they add, but it has not been clear whether bloodcalcium levels have any relationship to cognitive function.
To investigate, the researchers analyzed results of theRotterdam study, in which nearly 8,000 people 75 and older werefollowed for about 11 years, and the Leiden study, whichincluded almost 600 men and women aged 85 who were followeduntil they were 90.
In both groups, Schram and her team found, higher bloodcalcium was related to worse cognitive function at the study'soutset as measured by a test known as the Mini-Mental StateExamination. Poorer memory and executive function also wereassociated with higher calcium levels.
Higher calcium levels were also tied to faster mentaldecline over time in the Rotterdam study, but not in the moreelderly group in the Leiden study.
When the researchers excluded people with abnormally highcalcium levels from their analysis, the link between calciumlevels and cognitive function was actually strengthened.
More study is needed, the researchers conclude, tounderstand the mechanisms by which calcium levels both withinand outside nerve cells might contribute to mental decline.
SOURCE: Journal of the American Geriatrics Society,November 2007.