Association of magnesium depletion score with cognitive function in older adults: An analysis of US National Health and Nutrition Examination Survey (NHANES) 2011 to 2014

This study aims to explore the association between the magnesium depletion score (MDS), a newly developed indicator of magnesium levels, and cognitive function in older adults residing in the United States. We analyzed data from 768 participants aged ≥ 60 years in the 2011 to 2014 National Health and Nutrition Examination Survey. Participants were stratified by MDS levels: none-to-low (0-1), moderate (2), and high (3-5). Cognitive function was assessed through digit symbol substitution test (DSST), animal fluency test (AFT), and Consortium to Establish a Registry for Alzheimer's Disease Word Learning subtest. Using National Health and Nutrition Examination Survey mobile examination center weights, sample-weighted multivariable linear regression models calculated β coefficients (95% confidence intervals) for MDS-cognition associations, adjusting for age, sex, race, education, income, body mass index, smoking, and hypertension. In fully-adjusted models, high MDS group showed significantly lower cognitive scores versus none-to-low group: DSST: β = -4.91 (-7.73, -2.08), P = .0007, AFT: β = -2.09 (-3.25, -0.93), P = .0004. No significant association with Consortium to Establish a Registry for Alzheimer Disease scores (β = -0.96 [-2.25, 0.33], P = .1445). Stratified analyses revealed stronger associations in obese (body mass index > 30 kg/m²) and current smoking subgroups. Participants meeting magnesium recommended dietary allowance showed attenuated cognitive risks in DSST (interaction P = .022) and AFT (interaction P = .015). Higher MDS is independently associated with poorer processing speed and executive function in older Americans, particularly among obese individuals and smokers. Achieving dietary magnesium recommended dietary allowance may mitigate these low cognitive function. In our cross-sectional study, MDS was found to be associated with cognitive vulnerability.