Magnesium intake and all-cause mortality after stroke: a cohort study

BACKGROUND: Population-based studies have shown that adequate magnesium intake is associated with a lower risk of stroke and all-cause mortality. Whether adequate magnesium intake is important for reducing all-cause mortality risk after stroke remains unclear. METHODS: We analyzed data from 917 patients with a self-reported history of stroke from the National Health and Nutrition Examination Survey (NHANES) 2007–2018. The total magnesium intake was calculated by summing the magnesium intake from dietary and dietary supplements, and then adjusting for total energy intake according to the nutrient density method. Mortality status was determined using public-use linked mortality files from 2019. Cox regression model and restricted cubic splines were used to explore the relationship between magnesium intake and all-cause mortality. RESULTS: The average total magnesium intake across all patients was 251.0 (184.5–336.5) mg/d, and 321 (70.2%) males and 339 (73.7%) females had insufficient magnesium intake. During a median follow-up period of 5.3 years, 277 deaths occurred. After fully adjusting for confounding factors, total magnesium intake levels were inversely associated with all-cause mortality risk (HR per 1-mg/(100 kcal*d) increase, 0.97; 95% CI, 0.94–1.00; p = 0.017). Participants with the highest quartile of total magnesium intake (≥ 18.5 mg/(100 kcal*d)) had a 40% reduction in all-cause mortality risk compared to those with the lowest quartile (≤ 12.0 mg/(100 kcal*d)) (HR, 0.60; 95% CI, 0.38–0.94; p = 0.024). Stratified analyses showed that this inverse association was statistically significant in those who were older, female, without hypertension, and had smoking, normal renal function, and adequate energy intake. Dietary magnesium intake alone might be not related to all-cause mortality. CONCLUSIONS: Stroke survivors who consumed adequate amounts of magnesium from diet and supplements had a lower risk of all-cause mortality. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12937-023-00886-1.