Cross-sectional and longitudinal associations of magnesium intake and cognition in the Healthy Aging Longitudinal Study in Taiwan

Purpose: Previous cross-sectional studies have shown that higher magnesium intake is associated with better cognitive function, particularly in individuals with sufficient vitamin D status. The aim of this study was to evaluate the longitudinal associations between magnesium intake and cognitive impairment in a community-based cohort study in Taiwan. Methods: The study population included 5663 community-dwelling adults aged ≥ 55 years old recruited from 2009 to 2013 and followed up from 2013 to 2020. Magnesium intake was evaluated from a validated food frequency questionnaire at baseline. Cognitive performance was measured at baseline and follow-up for participants’ Mini-Mental Status Examination (MMSE), Digit Symbol Substitution Test (DSST), and Clock-Drawing Test (CDT), and impairment was defined as MMSE < 24, DSST < 21, and CDT < 3, respectively. Multivariate logistic regression models were used to examine the associations and were stratified by sex and plasma vitamin D levels (≥ 50 or < 50 nmol/L). Results: Higher baseline magnesium intake was associated with lower odds of a poor performance on the MMSE in both men and women (4th vs. 1st. quartile: OR = 0.43, 95% CI = 0.23–0.82, p_trend < 0.01 in men and OR = 0.53, 95% CI = 0.29–0.97, p_trend = 0.12 in women) and on the DSST in men (OR = 0.23, 95% CI = 0.09–0.61, p_trend < 0.01) at follow-up. Inverse associations between baseline magnesium intake and a poor performance on the MMSE or DSST were observed in men regardless of vitamin D status. Conclusion: Our study suggested that higher magnesium intake was associated with the development of cognitive impairment in men in a median follow-up period of 6 years.