Hyponatremia and osteoporosis: reappraisal of a novel association

Abstract

Summary Age was a modifier of the independent association between hyponatremia and osteoporosis (OP). Risk of OP was the highest in the youngest age group as compared to older patients. A longer duration of hyponatremia revealed a similar association with OP in all anatomical sites. Introduction Epidemiologic studies provide conflicting results on the relationship between hyponatremia and OP. Our aim is to test the modification effect of age on the relationship between hyponatremia and OP at various anatomical sites in a large patient population. Methods This is a cross-sectional observation of consecutive patients with available bone densitometry, demographic, clinical, and laboratory data from 2001 to 2013 at a single center. OP was defined as a bone mineral density of ≤2.5 standard deviations below the mean peak bone mass of young, healthy adults. Hyponatremia was defined as serum sodium ≤135 mmol/L. Multiple logistic regressions were used to calculate adjusted odds ratio (OR). Results Overall, 24,784 patients were included. There were 4549 males (18.4 %). Hyponatremia was present in 703 patients (2.8 %), femoral neck OP in 2603 (10.5 %), total hip OP in 1885 (7.5 %), and lumbar OP in 4830 (19.5 %). Total hip OP occurred in 17.6 % (n=124) of patients with hyponatremia as compared to 6.6 % (n=880) of patients with sodium level of “140–145” mmol/L (P<0.001). After multivariable adjustments, hyponatremia was associated with 2.46-fold higher odds of total hip OP (95 % CI, 1.36 to 4.46) in age <55 years, 1.96-fold (1.13 to 3.41) in age 55 to 67 years, and 1.55-fold (1.13 to 2.12) in age >67 years (age-sodium category interaction P value=0.002). Conclusions Age appeared as a modifier of the independent association between hyponatremia and OP. Risk of OP was the highest in the youngest age group as compared to older patients.

Hyponatremia Is Associated With Increased Osteoporosis and Bone Fractures in a Large US Health System Population

“…A study of single serum Na ϩ values 14 days before or after imaging suggested a modest dose-response between increasing serum Na ϩ and increasing total hip bone mineral content, BMD, and T-score (20). A recent study of dual-energy x-ray absorptiometry data from patients who had at least one hyponatremic interval in the 2 years prior to densitometry suggested that more severe and longer duration hyponatremia was associated with highest risk of osteoporosis in younger patients (21). The present study provides further evidence that the association between hyponatremia and osteoporosis is dose dependent (more severe hyponatremia results in higher elevated risk) and time dependent (chronic hyponatremia results carries higher risk than prior hyponatremia alone).…”

Hyponatremia, bone mineral density and falls in the elderly; Results from AHAP study

“…Other study conducted in the University of Michigan showed that hip osteoporosis occurred in 17.6 % of patients with HN as compared to 6.6 % of patients with normal serum sodium level, but osteoporosis was higher in younger age group (less than 55 years) as compared to older adults [13]. Considering different results in previous studies which may be due to the region where study participants were living and different underlying conditions; outcome variables which have been measured in the study protocol; and cut-off points of serum sodium concentration for determination of HN, this research has been proposed to assess the association of HN with bone density and falls in older population of Amirkola, Northern Iran.…”

“…Nearly, one third of body sodium is stored in the bone [25]. The association of HN with balance impairment, falls and bone fractures in the elderly can be justified by different mechanisms including increase unsteady gait related to cognitive impairment; bone resorption and its fragility [1,7,8,25], furthermore, another research presented that the sustained low extracellular sodium ion concentrations could directly stimulate osteoclastogenesis and that hyponatremia-induced oxidative stress might be involved in the mechanism [26].…”

Low extracellular sodium promotes adipogenic commitment of human mesenchymal stromal cells: a novel mechanism for chronic hyponatremia-induced bone loss

“…Experimental and clinical evidence have indicated in recent years that hyponatremia may negatively affect bone health [5,6,[8][9][10][11][12][15][16][17]. This study focused on the comprehension of the mechanisms leading to bone frailty in the presence of reduced [Na ? ]…”

“…Moreover, the risk of osteoporosis appeared to be higher in hyponatremic patients aged less than 55 years, suggesting that chronic hyponatremia may translate early aging of bone in young individuals. [16].…”