Vitamin D intoxication by increasing calcium absorption is known to cause and increase risk of calcium based kidney stones. It's unclear, however, to what extent physiologic doses of vitamin D alone increases this risk, as it's often given along with calcium to preserve bone health. Intake shouldn’t exceed the recommended age-specific daily limits, especially in patients at high-risk for stone formation.

The use of vitamin D and calcium (calcium 1,000 mg and vitamin D 400 IU) daily by postmenopausal women was associated with a 17% increase in risk of kidney stones over 7 years in the Women’s Health Initiative. You need to consider the risk/benefit ratio in individuals at risk for bone loss and kidney stones. It’s important not to exceed the age-specific limits of supplementation.

You may consider measuring urinary calcium excretion before and about a month after initiating calcium/vitamin D supplementation. If there’s significant increase in urinary calcium excretion, then reassess the need or consider a thiazide diuretic as an option to decrease urinary calcium excretion.