Excessive salt intake reduces bone density in the general female population

Osteoporosis is a multifactorial disorder in which nutrition is associated with its onset and progression. Excessive salt intake is closely associated with the onset and progression of various diseases, such as osteoporosis and hypertension. We investigated the effects of dietary salt intake on bone density in the general female population.In 884 female participants (60.1 ± 10.1 years old) who visited our hospital for an annual physical checkup, salt intake (g/day) was assessed using a spot urine sample, and bone density was evaluated as a speed of sound (m/s) of ultrasonic pulses in a calcaneus by quantitative ultrasound. We investigated the relationship between bone density and salt intake and the differences in bone density or salt intake between the presence and absence of lifestyle-related diseases such as hypertension, diabetes mellitus and dyslipidaemia.The average bone density and salt intake were 1497 ± 26 m/s and 8.5 ± 1.8 g/day, respectively. Univariate and multivariate regression analyses revealed that bone density was significantly negatively associated with salt intake. Bone density was lower, and salt intake was higher in participants with hypertension, diabetes mellitus and dyslipidaemia than in those without. After adjusting for age, hypertension, diabetes mellitus and dyslipidaemia, bone density was negatively correlated with salt intake.We confirmed that excessive salt intake reduces bone density independently of age and lifestyle-related diseases in the general female population. Since dietary salt intake is a modifiable factor, osteoporosis can be prevented by dietary intervention, including salt reduction.