High dietary sodium intake is associated with low bone mass in postmenopausal women: Korea National Health and Nutrition Examination Survey, 2008-2011

The present cross-sectional study performed using data from the Korea National Health and Nutrition Examination Survey in 9526 women older than 18 years of age demonstrates that high sodium intake is associated with lower bone mineral density and sodium intake a 2000 mg/day is a risk factor for osteoporosis in postmenopausal women. Several studies have reported that large amount of dietary sodium intake is highly associated with elevated urinary calcium. However, the direct effect of excessive dietary sodium intake on bone mass, as a risk factor for osteoporosis, is still a controversial issue. The aim of the present study was to assess the relationship between high intake of sodium and lower bone mass and risk of osteoporosis in adult women. This cross-sectional study was performed using data from the Korea National Health and Nutrition Examination Survey (KNHANES), 2008-2011. Participants (n = 9526 women older than 18 years) were divided into a premenopausal (n = 4793) and postmenopausal (n = 4733) group. Both groups were subdivided into five groups according to quintiles of energy-adjusted sodium intake. Multiple regression analysis was performed to assess relationships between sodium intake and lower bone mass. Multivariate linear regression analysis showed that high sodium intake was negatively associated with bone mineral content (BMC) and bone mineral density (BMD) in postmenopausal women. After adjusting confounding factors, high sodium intake was negatively associated with BMC and BMD of the lumbar spine in postmenopausal women. Postmenopausal women, whose sodium intake was a 2000 mg/day (odds ratio 1.284, 95% CI 1.029-1.603, P = 0.027), were at risk of developing osteoporosis after adjustment of confounding variables. The present study suggested that high sodium intake could be a potential risk factor for low bone mass after adjusting for confounding factors in postmenopausal women.