Neuroendocrine Unit, Bulfinch 457B, Massachusetts General Hospital, Boston, MA 02114, USA.
J Clin Psychiatry. 2012 Nov;73(11):e1379-83. doi: 10.4088/JCP.12m07919.
Anorexia nervosa is a psychiatric disorder characterized by restrictive eating, low body weight, and severe bone loss. Recent data show a deleterious relationship between low circulating sodium levels and bone mass, and relative or absolute hyponatremia is a known complication of anorexia nervosa. Clinical studies of other medical conditions associated with hyponatremia suggest that detrimental effects of low sodium levels on health are seen even within the normal range. We hypothesized that women with anorexia nervosa and relatively low plasma sodium levels would have lower bone mineral density (BMD) than those with higher plasma sodium levels.
In a cross-sectional study (January 1, 1997-December 31, 2009) of 404 women aged 17 to 54 years (mean ± standard error of the mean [SEM] age = 25.6 ± 0.3 years) who met DSM-IV criteria for anorexia nervosa, we measured BMD using dual-energy x-ray absorptiometry. Bone mineral density was compared in women with plasma sodium levels < 140 mmol/L (midpoint of normal range) versus those with plasma sodium levels ≥ 140 mmol/L and in women with hyponatremia (plasma sodium < 135 mmol/L) versus those without. The study was conducted at the Neuroendocrine Unit of Massachusetts General Hospital, Boston.
Women with plasma sodium levels < 140 mmol/L had significantly lower BMD and t and z scores versus those with plasma sodium levels ≥ 140 mmol/L at the anterior-posterior (AP) spine (mean ± SEM z scores = -1.6 ± 0.1 vs -1.3 ± 0.1, P = .004) and total hip (mean ± SEM z scores = -1.2 ± 0.1 vs -0.9 ± 0.1, P = .029). In a model controlling for age, BMI, psychiatric drug use, and disease duration, differences in BMD and t and z scores remained significant at the AP spine. Women with hyponatremia had significantly lower BMD and t and z scores versus those without hyponatremia at the AP spine (mean ± SEM z scores = -2.2 ± 0.3 vs -1.3 ± 0.1, P = .009), lateral spine (mean ± SEM z scores = -2.4 ± 0.4 vs -1.5 ± 0.1, P = .031), and total hip (mean ± SEM z scores = -2.5 ± 0.5 vs -1.0 ± 0.1, P < .0001). In a model controlling for age, BMI, psychiatric drug use, and disease duration, differences in BMD and z and t scores remained significant at all sites.
These data suggest that relative plasma sodium deficiency may contribute to anorexia nervosa-related osteopenia.
神经性厌食症是一种以饮食限制、体重过低和严重骨质流失为特征的精神疾病。最近的数据显示，循环中钠水平低与骨量之间存在有害关系，相对或绝对低钠血症是神经性厌食症的已知并发症。对其他与低钠血症相关的医学病症的临床研究表明，即使在正常范围内，低钠水平对健康的有害影响也会显现出来。我们假设，患有神经性厌食症且血浆钠水平相对较低的女性的骨矿物质密度（BMD）会低于血浆钠水平较高的女性。
在一项横断面研究中（1997 年 1 月 1 日至 2009 年 12 月 31 日），我们对 404 名年龄在 17 至 54 岁之间（平均 ± 标准误差[SEM]年龄= 25.6 ± 0.3 岁）的符合 DSM-IV 标准的神经性厌食症女性进行了研究，我们使用双能 X 射线吸收法测量了 BMD。我们比较了血浆钠水平 < 140 mmol/L（正常范围中点）的女性与血浆钠水平≥140 mmol/L 的女性以及低钠血症（血浆钠 < 135 mmol/L）的女性与无低钠血症的女性的 BMD。该研究在波士顿马萨诸塞州总医院的神经内分泌科进行。
与血浆钠水平≥140 mmol/L 的女性相比，血浆钠水平<140 mmol/L 的女性在前后（AP）脊柱（平均 ± SEM z 评分=-1.6 ± 0.1 比-1.3 ± 0.1，P=0.004）和总髋部（平均 ± SEM z 评分=-1.2 ± 0.1 比-0.9 ± 0.1，P=0.029）的 BMD 和 t 值和 z 值明显更低。在控制年龄、BMI、精神科药物使用和疾病持续时间的模型中，AP 脊柱的 BMD 和 t 值和 z 值差异仍然具有统计学意义。与无低钠血症的女性相比，患有低钠血症的女性的 BMD 和 t 值和 z 值在前后（平均 ± SEM z 评分=-2.2 ± 0.3 比-1.3 ± 0.1，P=0.009）、侧脊柱（平均 ± SEM z 评分=-2.4 ± 0.4 比-1.5 ± 0.1，P=0.031）和总髋部（平均 ± SEM z 评分=-2.5 ± 0.5 比-1.0 ± 0.1，P<0.0001）的 BMD 和 t 值和 z 值明显更低。在控制年龄、BMI、精神科药物使用和疾病持续时间的模型中，所有部位的 BMD 和 z 值和 t 值差异仍然具有统计学意义。
这些数据表明，相对血浆钠缺乏可能导致神经性厌食症相关的骨质疏松症。
