New clusters of serum electrolytes aid in stratification of diabetes and metabolic risk

Serum sodium level is inversely associated with new-onset diabetes in hypertensive patients

BACKGROUND

Serum sodium level is associated with cardiovascular and endocrine health. Though decreased serum sodium is considered to be associated with reduced hypertension risk, some studies also found that it may increase the risk of diabetes. This study aimed to investigate the association of serum sodium with new-onset diabetes in hypertensive patients.

METHODS

Based on the annual health examinations from 2011 to 2016 in Dongguan City, Guangdong, China, hypertensive patients without diabetes at baseline were selected. Logistic regression and restricted cubic spline were used to evaluate the association between serum sodium level and new-onset diabetes. Subgroup analysis was also conducted.

RESULTS

A total of 4438 hypertensive patients with a mean age of 58.65 years were included, of whom 48.9% were male. During a median follow-up of 35.1 months, 617 (13.9%) of the subjects developed new-onset diabetes. Per 1-SD (3.39 mmol/L) increment of serum sodium was associated with a 14% lower risk of new-onset diabetes (odds ratio = 0.86; 95% CI: 0.78, 0.97; p = 0.01). The lowest quartile of serum sodium was associated with the lowest diabetes risk. The restricted cubic spline showed a linear inverse relationship (nonlinear p = 0.72). Across all the subgroups, the inverse association was consistent (p for interaction >0.05).

CONCLUSION

An inverse association of serum sodium with new-onset diabetes in hypertensive patients was observed.

The association between normal serum sodium levels and bone turnover in patients with type 2 diabetes

BACKGROUND

Sodium is a critically important component of bones, and hyponatremia has firmly been established as a risk factor associated with the incidence of fragility fractures. However, researches have also revealed that lower serum sodium are linked to reductions in muscle mass and a higher risk of cardiovascular disease even when these levels are within the normal range. Accordingly, this study was developed to examine the relationships between normal serum sodium concentrations and bone turnover in patients with type 2 diabetes (T2D).

METHODS

Patients with T2D were enrolled in the present study from January 2021 to April 2022. All patients underwent analyses of serum sodium levels, oral glucose tolerance testing (OGTT), bone turnover markers (BTMs), and dual-energy X-ray absorptiometry (DXA) scanning. BTMs included bone formation markers osteocalcin (OC) and N-terminal propeptide of type-I procollagen (PINP), and bone resorption marker C-terminal telopeptide (CTx). Patients were stratified into three subgroups based on the tertiles of their serum sodium concentrations.

RESULTS

In total, 372 patients with T2D and sodium levels in the normal range were enrolled in this study. Serum OC and PINP levels were increased from subgroup with the low sodium tertile to that with the high sodium tertile (p for trend < 0.05), whereas CTx level was comparable among the subgroups. A positive correlation was detected between serum sodium levels and both lnOC (r = 0.210, p < 0.001) and lnPINP (r = 0.196, p < 0.001), with these relationships remaining significant even following adjustment for age, sex, body mass index (BMI), and HbA1c. Only after adjusting for these four factors a positive correlation was detected between serum sodium levels and CTx levels (r = 0.108, p < 0.05). Linear regression analyses revealed that following adjustment for potential covariates, serum sodium level was and positively significantly associated with lnOC level (β = 0.134, t = 2.281, p < 0.05) and PINP level (β = 0.179, t = 3.023, p < 0.01).

CONCLUSION

These results highlight a significant association between low-normal serum sodium levels and low bone turnover.