Departments of Community Healthcare and Geriatrics, Graduate School of Medicine, Nagoya University, 65 Tsurumai-cho, Showa-ku, Nagoya City, Aichi, 466-8550, Japan.
Center for Comprehensive Care and Research on Memory Disorders, National Center for Geriatrics and Gerontology, Obu, Japan.
BMC Geriatr. 2021 Jan 6;21(1):15. doi: 10.1186/s12877-020-01955-4.
Mild hyponatremia (serum sodium 130-135 mEq/L) is a common electrolyte disorder in the elderly. However, its association with both sarcopenia and cognitive function remains to be clarified. Therefore, here we investigated the association of mild hyponatremia with skeletal muscle mass, physical function, and cognitive function in the elderly.
We enrolled 75 participants with mild hyponatremia and 2907 with normonatremia (serum sodium, 136-145 mEq/L) aged ≥70 years who visited the Memory Disorder Outpatient Center of Japan's National Center for Geriatrics and Gerontology. Skeletal muscle mass index (SMI), grip strength (GS), walking speed (WS), one-leg standing (OLS) test times, and neuropsychological test scores were determined.
One-way analysis of covariance showed that elderly participants with mild hyponatremia had lower SMI (7.1 ± 0.2, 7.2 ± 0.2 kg/m, p = 0.04), weaker GS (19.1 ± 1.9 vs 21.4 ± 1.8 kg, p = 0.01), slower WS (0.9 ± 0.1 vs 1.1 ± 0.1 m/s, p = 0.001), and higher GDS- 15 score (6.4 ± 0.9 vs 5.2 ± 0.9, p = 0.002) than those with normonatremia. Multiple logistic regression analysis indicated that mild hyponatremia was independently associated with sarcopenia (odds ratio [OR]: 2.2, p = 0.02), slower WS (OR: 5.3, p = 0.04) and shorter OLS time (OR: 2.5, p = 0.02) as well as with severe depressive mood (OR: 2.6 p = 0.006) but not with SMI (OR: 1.6, p = 0.2) or GS (OR: 1.9, p = 0.09).
Our results suggest that elderly people with even mild hyponatremia had physical function impairment and depressive mood.
轻度低钠血症（血清钠 130-135mEq/L）是老年人中常见的电解质紊乱。然而，其与肌肉减少症和认知功能的关系仍需阐明。因此，我们在此研究了轻度低钠血症与老年人的骨骼肌量、身体功能和认知功能之间的关系。
我们招募了 75 名患有轻度低钠血症的患者和 2907 名血清钠在 136-145mEq/L 之间的正常钠血症（血清钠，136-145mEq/L）患者，年龄均≥70 岁，他们均就诊于日本国家老年医学与老年学中心的记忆障碍门诊中心。确定了骨骼肌量指数（SMI）、握力（GS）、步行速度（WS）、单腿站立（OLS）测试时间和神经心理学测试评分。
单因素方差分析显示，患有轻度低钠血症的老年患者的 SMI 较低（7.1±0.2，7.2±0.2kg/m，p=0.04），GS 较弱（19.1±1.9 与 21.4±1.8kg，p=0.01），WS 较慢（0.9±0.1 与 1.1±0.1m/s，p=0.001），GDS-15 评分较高（6.4±0.9 与 5.2±0.9，p=0.002）。多因素 logistic 回归分析表明，轻度低钠血症与肌肉减少症（比值比[OR]：2.2，p=0.02）、WS 较慢（OR：5.3，p=0.04）和 OLS 时间较短（OR：2.5，p=0.02）以及严重抑郁情绪（OR：2.6，p=0.006）独立相关，但与 SMI（OR：1.6，p=0.2）或 GS（OR：1.9，p=0.09）无关。
我们的研究结果表明，即使是轻度低钠血症的老年人也存在身体功能障碍和抑郁情绪。
