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

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.

The Change of Urine Deoxypyridinoline in a Patient with Symptomatic Hypercalcemia associated with Hyperthyroidism / 대한골다공증학회지

Malignancy and primary hyperparathyroidism are the common causes of hypercalcemia. Although hyperthyroidism may induce mild asymptomatic hypercalcemia, it is very rare that hyperthyroidism causes symptomatic hypercalcemia with a serum calcium concentration > or = 11 mg/dL. A 47-year-old woman visited our hospital for evaluation of nausea, vomiting, and urinary frequency. Her corrected total calcium level was 12.0 mg/dL. She was diagnosed with hyperthyroidism. We excluded the common causes of hypercalcemia by measurements of serum intact parathyroid hormone and a diagnostic work-up for malignancy. She was treated with propranolol and methimazole. The serum calcium and urine deoxypyridinoline, as a bone resorption marker, decreased and hypercalcemic symptoms resolved completely after restoration of the biochemical euthyroid state. In case of difficulty in excluding other causes of hypercalcemia in hyperthyroid patients, the follow-up of changes of bone turnover marker and level of serum calcium can be helpful.