The relationship between potassium and magnesium status and health outcomes: mortality and neurological performance

Autor: Ying-Ho Lai, 賴瑩荷
Rok vydání: 2015
Druh dokumentu: 學位論文 ; thesis
Popis: 103
Stroke is among the leading causes of death, which can cause to permanent neurological deficits and affect quality of life. Potassium and magnesium, two essential minerals, play important roles in the pathogenesis of hypertension, diabetes, and stroke. Dietary sodium excess contributes to the blood pressure elevation with age and increases the risk of stroke. Potassium can counteract the effect of sodium on hypertension and protect against stroke mortality. Magnesium nutriture has been associated with diabetes risk and severity of stroke symptom. Intravenous provision of magnesium to acute phase stroke patients has been vigorously studied but with controversial findings. It is lacking studies to investigate the association between nutritional status of these minerals and the long-term cerebrovascular outcomes of high risk groups such as elderly and stroke patients. Study 1. Association study between serum potassium and risk of cardiovascular and all-cause death in community-based elderly （Prospective study） Background/Purpose: Several studies have already reported that serum potassium (SK) correlated inversely with adverse event among patients with pre-existing cardiovascular disease and impaired renal function; less is known about the prognostic value of SK at the normal range in community-based elderly individuals. Objective: This study aimed to examine whether low normal or high normal SK value was associated with cardiovascular and all-cause mortalities in elderly people. Methods: Perspective study using two independent elderly Taiwanese community cohorts which included 2065 subjects with relatively normal SK values (2.8-5.6 mmol/L). Subjects were grouped into: low (2.8-3.4 mmol/L), low-normal SK (3.5–3.8 mmol/L), normal (3.9–4.4 mmol/L), and high-normal SK (4.5–5.6 mmol/L). Proportional hazards model was applied to compare the association between SK concentration groups and mortality. Results: The relationship between baseline SK and all-cause and cardiovascular mortality was U-shaped, with the lowest mortality rates observed in patients with SK levels of 3.9 to 4.4 mmol/L. The low-normal SK group had significantly higher risk of all-cause (HR, 1.3; 95% CI, 1.0–1.6) and cardiovascular mortalities (HR, 1.6; 95% CI, 1.1–2.3) than the normal SK group. The high normal SK group had higher but non-significant risk compared to the normal. Conclusion: Our findings suggest that low-normal SK may be used as a marker of poor survival for elderly outpatient cares. Study 2. The effect of intervention with potassium and/ or magnesium-enriched salt on neurological performance of stroke patients (Multi-center clinical trial) Background: Stroke is one of the leading causes of mortality and neurological deficits. Adequate dietary potassium is associated with reduced risk of hypertension and stroke. Our previous 3.5-year intervention trial in the elderly demonstrated a 41%-reduction in cardiovascular mortality from switching to potassium-enriched salt. Since dietary magnesium has been associated with lowered diabetes/stroke risk in human and neuroprotection in animal and salt is a good carrier for mineral; it is justifiable to study whether further enriching salt with magnesium may provide additional benefit for stroke recovery, at the level near but not beyond the daily recommended intake level (DRI). Methods: A multi-centered randomized controlled trial was carried out with three arms: (1) regular salt (Na salt), (2) potassium-enriched salt (K salt), and (3) potassium and magnesium-enriched salt (K/Mg salt). The NIHSS, Barthel Index (BI) and mRS were evaluated at baseline, 3 month, and 6 month. Results: A significantly higher percentage of patients with mRS≦1was observed for both the K/Mg and the K groups at 3rd (p=0.01 and 0.03, respectively) and 6th months (p=0.005 and 0.01) than baseline. This phenomenon is not apparent in the Na group. The K/Mg group had a significantly increased odds ratio of achieving good neurological performance defined by a combination of 3 indices, compared with the Na group (odds ratio, 1.77; p=0.035) and with the K group (odds ratio, 1.70; p-0.057). Conclusion: This study suggests that long-term replenishing magnesium to reach DRI is beneficial for stroke patients to recover from neurological injuries.
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