Background: High serum calcium levels have been associated with cognitive decline in older adults. These associations have not been studied in younger adults. The possible association of vitamin D with cognitive function, independent of calcium, is unknown.
Methods: A cross-sectional study of associations of serum ionized calcium and 25-hydroxyvitamin D levels with cognitive function in younger adults (20-59 years) and older adults (60-90 years) was conducted using data from the US third National Health and Nutrition Examination Survey (NHANES III).
Results: Neither serum ionized calcium nor 25-hydroxyvitamin D was associated with cognitive function in either age group. For example, the confounder-adjusted mean difference in reaction time in young adults was 0.00 (95% confidence interval = −0.07 to 0.06) per 1 SD calcium.
Conclusion: Our results do not support an important role for calcium or vitamin D in cognitive performance in adults.
From the MRC Centre for Causal Analyses in Translational Epidemiology, School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom.
Submitted 30 March 2010; accepted 7 July 2010; posted 28 September 2010.
Supported by an UK MRC Grant (G0701603), which also pays AMT's salary. The UK Medical Research Council (MRC) and the University of Bristol provide core funding for the MRC Centre of Causal Analyses in Translational Epidemiology (G0600705). DW is funded by a Wellcome Trust 4-year PhD studentship in Molecular, genetic, and lifecourse epidemiology (WT083431MA).
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Correspondence: Anna-Maija Tolppanen, Centre for Causal Analyses in Translational Epidemiology, School of Social and Community Medicine, University of Bristol, Bristol, UK Oakfield House, 15-23 Oakfield Grove, Clifton, Bristol BS8 2BN, UK. E-mail: email@example.com.