Association of urinary sodium/creatinine ratio with bone mineral density in postmenopausal women: KNHANES 2008–2011

Abstract

Accumulating evidence shows that high sodium chloride intake increases urinary calcium excretion and may be a risk factor for osteoporosis. However, the effect of oral sodium chloride intake on bone mineral density (BMD) and risk of osteoporosis has been inadequately researched. The aim of the present study was to determine whether urinary sodium excretion (reflecting oral sodium chloride intake) associates with BMD and prevalence of osteoporosis in postmenopausal women. This cross-sectional study involved a nationally representative sample consisting of 2,779 postmenopausal women who participated in the Korea National Health and Nutritional Examination Surveys in 2008-2011. The association of urinary sodium/creatinine ratio with BMD and other osteoporosis risk factors was assessed. In addition, the prevalence of osteoporosis was assessed in four groups with different urinary sodium/creatinine ratios. Participants with osteoporosis had significantly higher urinary sodium/creatinine ratios than the participants without osteoporosis. After adjusting for multiple confounding factors, urinary sodium/creatinine ratio correlated inversely with lumbar spine BMD (P = 0.001). Similarly, when participants were divided into quartile groups according to urinary sodium/creatinine ratio, the average BMD dropped as the urinary sodium/creatinine ratio increased. Multiple logistic regression analysis revealed that compared to quartile 1, quartile 4 had a significantly increased prevalence of lumbar spine osteoporosis (odds ratios 1.346, P for trend = 0.044). High urinary sodium excretion was significantly associated with low BMD and high prevalence of osteoporosis in lumbar spine. These results suggest that high sodium chloride intake decreases lumbar spine BMD and increases the risk of osteoporosis in postmenopausal women.

The Science of Salt: A Regularly Updated Systematic Review of Salt and Health Outcomes (August to November 2015)

“…The search identified 1571 citations, of which 145 possibly relevant studies met the criteria for full review on the basis of their findings related to salt and health outcomes ( Figure). A total of 15 dietary salt studies were included: 12 observational studies, [9][10][11][12][13][14][15][16][17][18][19][20] two RCTs, 21,22 and one meta-analysis. 23 The primary outcomes of the included studies were varied: one study assessed cardiovascular events 9 ; five studies assessed BP or hypertension incidence [10][11][12][13]21 ; six studies assessed surrogate outcomes for cardiovascular 14,22 or kidney diseases [15][16][17]23 ; and three studies assessed other outcomes, including age-related cataracts, 18 rheumatoid arthritis, 19 and bone mineral density.…”

“…23 The primary outcomes of the included studies were varied: one study assessed cardiovascular events 9 ; five studies assessed BP or hypertension incidence [10][11][12][13]21 ; six studies assessed surrogate outcomes for cardiovascular 14,22 or kidney diseases [15][16][17]23 ; and three studies assessed other outcomes, including age-related cataracts, 18 rheumatoid arthritis, 19 and bone mineral density. 20 Descriptions of the 15 included studies are listed in the Table. Detailed risk of bias assessments for all included studies are included in Appendix S1. Four studies were selected for detailed commentary below: a cross-sectional study assessing the association between dietary sodium and obesity, 14 an RCT comparing the effect of a light salt substitute vs regular salt on BP, 21 an RCT comparing the effect of sodium supplementation and potassium supplementation on endothelial function, 22 and a meta-analysis of the effect of dietary sodium on albuminuria.…”

Association between Urinary Sodium Excretion and Bone Health in Male and Female Adults

“…This finding is similar to the results of other reports. Recently, Kim et al [13] performed a cross-sectional study using 2,779 postmenopausal women who participated in the KNHANES 2008-2011. They reported that high urinary sodium excretion was significantly associated with low BMD and high prevalence of osteoporosis in lumbar spine.…”

High salt intake: detrimental not only for blood pressure, but also for bone health?

“…While it becomes obvious that the amount of NaCl in daily diet is related to the risk of cardiovascular events, influences of NaCl intake on other health outcomes are less well examined. In this issue of Endocrine, Kim et al present data from the 2008 to 2011 Korea National Health and Nutritional Examination Surveys, showing that high urinary sodium excretion was significantly associated with low BMD and high prevalence of osteoporosis in lumbar spine in postmenopausal women [3]. This is not the first report on an inverse relationship between salt intake and bone status densitometrically determined as BMD.…”

“…However, overall evidence is still rather low, due to (i) lacking interventional confirmation and (ii) the fact that several surveys did not find significant inverse relationships between salt intake and BMD. What, on the other hand, is regularly observed along with an increased salt intake, is a rise in renal calcium excretion (for the literature, refer to [3]). In this context, most authors speculate that the corresponding calcium loss is not appropriately compensated by an elevation in intestinal absorption, hence leading to a negative calcium balance with concomitant bone loss.…”