Abstract
BACKGROUND: Evidence on magnesium (Mg), depression, and sleep quality has been controversial. OBJECTIVES: We aimed to examine associations of serum and dietary Mg with depressive and insomnia symptoms in a prospective longitudinal cohort. METHODS: Adults from the Boston Puerto Rican Health Study who completed the Centre for Epidemiologic Studies Depression Scale (CES-D) assessment at any visit from baseline to the third visit (∼6-y follow-up) were included in analyses on Mg and depressive symptomatology (n = 1465 with Mg intake; n = 1116 with serum Mg). Linear mixed-effects models were used to estimate β coefficients. Mg measures at visit 2 were used to predict incident insomnia symptoms at visit 3 (n = 613 with Mg intake; n = 587 with serum Mg; median follow-up: ∼4 y). Logistic regression was used to estimate odds ratios (ORs). Diabetes, sex, baseline Mg status, and calcium:Mg intake ratio were evaluated as modifiers. RESULTS: No clear association was observed between Mg and CES-D score after adjustment for confounders. However, higher Mg intake from food was associated with less low positive affect, a dimension of CES-D {β [95% confidence interval (CI): -0.28 (-0.45, -0.11)]}. Mg was not associated with insomnia in the full sample. However, higher Mg intake and supplement use were associated with lower odds of insomnia in participants without diabetes [per 100 mg/d total Mg: OR (95% CI): 0.42 (0.23, 0.79); per 100 mg/d Mg from food: 0.41 (0.21, 0.79); Mg supplement users compared with nonusers: 0.37 (0.17, 0.81)], which was not found in participants with diabetes (P-interaction < 0.05). Serum Mg was not associated with either outcome. Limited interaction was detected for other potential modifiers, despite some subgroup variation in association direction or magnitude. CONCLUSIONS: Higher Mg intake was associated with lower odds of insomnia symptoms in Puerto Rican adults without diabetes. Furthermore, research is needed to investigate the role of diabetes in the Mg-sleep association.