The Association of Dietary and Urinary Sodium With Bone Mineral Density and Risk of Osteoporosis: A Systematic Review and Meta-Analysis

Objective: Although some earlier studies have indicated an association between dietary/urinary sodium and bone mass density (BMD), bone mass content (BMC), and the risk of osteoporosis (OS), findings are still conflicting. The aim of this study was to summarize the relation of dietary/urinary sodium with BMD, BMC, and the risk of OS.Methods: We conducted a systematic search up to April 2017 in PubMed/MEDLINE, SCOPUS, and Web of Science to find relevant studies. Articles with cross-sectional and cohort designs in which odds ratios (ORs), correlations (r), or beta coefficients were reported for the association between dietary/urinary sodium and OS, BMD, or BMC were included.Results: Pooling 11 effect sizes with a total of 39,065 people showed that higher sodium consumption significantly increased the risk of OS (OR = 1.20; 95% confidence interval [CI], 1.02-1.41; p = 0.026), with high heterogeneity among studies (I-2 = 68.0%; p = 0.001). Subgroup analyses showed significantly higher risk of OS in premenopausal women (OR = 1.31; 95% CI, 1.01-1.69; p = 0.036), in participants with a mean age older than 50years (OR = 1.15; 95% CI, 1.04-1.28; p = 0.005), in dietary sodium intake subgroup (OR = 1.45; 95% CI, 1.19-1.77; p < 0.001), and in individuals with adjustment for energy (OR = 1.77; 95% CI, 1.38-2.27; p < 0.001). The correlation coefficients showed no significant association between urinary sodium and BMD (r = -0.46; 95% CI, -0.74 to -0.18; p = 0.02).Conclusions: We found a positive association between sodium intake and the risk of OS, while no association was found with urinary sodium. Furthermore, there was no significant correlation between sodium intake and BMD. Due to high heterogeneity in this research, more studies are suggested.