The Association of Serum Ionized Calcium and Vitamin D With Adult Cognitive Performance

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.