J Bone Metab.  2014 Aug;21(3):189-194. 10.11005/jbm.2014.21.3.189.

High Dietary Sodium Intake Assessed by 24-hour Urine Specimen Increase Urinary Calcium Excretion and Bone Resorption Marker

• Park SM
• Jee J
• Joung JY
• Cho YY
• Sohn SY
• Jin SM
• Hur KY
• Kim JH
• Kim SW
• Chung JH
• Lee MK
• Min YK

• KMID: 2286288
• DOI: http://doi.org/10.11005/jbm.2014.21.3.189

Abstract

BACKGROUND
The average dietary sodium intake of Koreans is 2.6 times higher than the World Health Organization's recommended amount. The effect of a diet high in sodium on the skeletal system, especially osteoporosis, has not previously been examined in Korean postmenopausal women with low bone mass. We assessed the daily sodium intake, and determined the impact of sodium intake on urinary calcium excretion and bone resorption marker.
METHODS
A retrospective review of medical records was performed for 86 postmenopausal subjects who were initially diagnosed with osteopenia or osteoporosis at the health promotion center. They were subsequently referred to the Division of Endocrinology and Metabolism between 2010 and 2013. All subjects completed a modified food frequency questionnaire. Twenty-four hour urine collection for sodium, calcium and creatinine excretion, and serum C-terminal telopeptides of type I collagen (CTX-I) were also obtained.
RESULTS
The average amount of daily sodium and calcium intake were 3,466 mg and 813 mg, respectively. Average dietary sodium intake and 24-hour urinary sodium excretion showed significant positive linear correlation (r=0.29, P=0.006). There was also a significant positive linear correlation between 24-hour urine sodium and calcium excretion (r=0.42, P<0.001); CTX-I and 24-hour urinary calcium excretion (r=0.29, P=0.007).
CONCLUSIONS
Excessive sodium intake assessed by 24-hour urine specimen is associated with high calcium excretion in urine. High calcium excretion is also related to increasing bone resorption marker.

Keyword

Bone resorption marker; Dietary sodium intake; Urinary calcium excretion; Urinary sodium excretion

MeSH Terms

Bone Diseases, Metabolic
Bone Resorption*
Calcium*
Collagen Type I
Creatinine
Diet
Endocrinology
Female
Health Promotion
Humans
Medical Records
Metabolism
Osteoporosis
Retrospective Studies
Sodium
Sodium, Dietary*
Urine Specimen Collection
World Health
World Health Organization
Surveys and Questionnaires
Calcium
Collagen Type I
Creatinine
Sodium
Sodium, Dietary

Figure

• 

  Fig. 1 Association of the estimated sodium intake assessed by modified food frequency questionnaire (FFQ) and 24-hour urinary sodium excretion. (A) Correlation between daily sodium intake (mg/day) and 24-hour urinary sodium excretion (mg/mg Cr). (B) Differences between average amount of daily sodium intake assessed by the FFQ and the 24-hour urinary sodium excretion. Na, sodium; Cr, creatinine.

• 

  Fig. 2 Correlation of (A) 24-hour urinary sodium excretion and calcium excretion; (B) 24-hour urinary calcium excretion and serum C-terminal telopeptides of type I collagen. CTX-I, C-terminal crosslinking telopeptides of type I collagen; Ca, calcium.

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