February 11, 2016
2 min read

WHI: Sodium intake unlikely to affect osteoporosis risk in postmenopausal women

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Sodium intake that falls within the current guidelines does not significantly affect the risk for osteoporosis in postmenopausal women, according to an analysis of findings from the Women’s Health Initiative.

“That sodium intake was not associated with incident fractures, including all fractures, clinical spine fractures and other osteoporotic sites, is novel and important information,” Laura Carbone, MD, MS, FACP, division chief of rheumatology in the department of medicine at Medical College of Georgia, and colleagues wrote. “Theoretically, sodium intake might be a determinant of fractures at low calcium intakes. We did not observe this in the WHI, as at calcium intakes of 450 mg/day, there was no clear evidence of a relationship between sodium intake and incident fractures.”

Laura Carbone

Laura Carbone

Researchers analyzed data from 4,426 postmenopausal women participating in the Women’s Health Initiative, followed during a mean of 11.4 years. Researchers examined whether sodium intake was associated with changes in bone mineral density at the lumbar spine, total hip, femoral neck and total body, or with incident fractures, and whether the relationship was modified by potassium or calcium intake. Sodium and potassium intake, as well as dietary intake of calcium, magnesium and vitamin D, were assessed by food frequency questionnaire; incident clinical fractures were determined by self-report; BMD was measured at baseline, 3 and 6 years by DXA.

Within the cohort, the mean intake of sodium was 2,457.8 mg/day; mean biomarker calibrated sodium intake was 2,986.1 mg/day.

Researchers found no significant association between calibrated sodium intake and changes in BMD at the hip or lumbar spine from baseline to 3 or 6 years after adjustment.

After excluding participants with diabetes and those on medications associated with calibrated sodium intake, higher sodium intake was associated with an increase in total body BMD from baseline to 3 years (P = .0001) with a trend from baseline to 6 years (P = .06). Researchers also found increased sodium intake was associated with reduced hip fracture incidence (HR = 0.81; 95% CI, 0.67-0.97). However, in sensitivity analyses that included BMI as an additional covariate, there was no association between sodium intake and changes in BMD at any skeletal site or with incident fractures. Adjusting for potassium and calcium intake did not change the relationship.

Levels of sodium intake higher or lower than currently recommended guidelines for cardiovascular disease (< 2,300 mg/day) also were not associated with changes in BMD at any skeletal site from baseline to 3 years, from baseline to 6 years or with incident fractures.

“A low salt diet alone is unlikely to prevent osteoporotic fracture,” Carbone told Endocrine Today. “Substantial research is needed in this area. In particular, randomized clinical trials on the effects of varying levels of salt intake on outcomes such as changes in BMD, bone strength and fractures are needed.” – by Regina Schaffer

Disclosure: The researchers report no relevant financial disclosures.