BACKGROUND:

Vitamin D intoxication is associated with the mobilization of skeletal calcium.

OBJECTIVE:

To ascertain how the resolution of vitamin D intoxication affects bone density.

DESIGN:

Case series.

SETTING:

Referral service for metabolic bone disease in a tertiary care teaching hospital.

PATIENTS:

Four patients with osteoporosis who were each using several nonprescription dietary supplements and were found to have fasting hypercalciuria.

INTERVENTION:

Discontinuation of use of dietary supplements.

MEASUREMENTS:

Serial measurement of serum levels of 25-hydroxyvitamin D, ratio of fasting urinary calcium to creatinine, and bone mineral density for 3 years.

RESULTS:

Discontinuation of use of dietary supplements resulted in the normalization of serum levels of 25-hydroxyvitamin D, the normalization of the ratio of urinary calcium to creatinine, and a mean annual increase in bone mineral density (+/- SD) of 1.9% +/- 0.5%.

CONCLUSIONS:

Occult vitamin D intoxication was detected in patients who were using dietary supplements that contained an unadvertised high level of vitamin D. Resolution of vitamin D intoxication was associated with a rebound in bone mineral density.