An Athletic Teen Suddenly Prone to Falls and Fractures

Inas H. Thomas, MD


June 06, 2022

The Endocrine Society Clinical Practice Guidelines for evaluation, treatment, and prevention of vitamin D deficiency released in 2011 gave recommendations for the amount of vitamin D per age group.[5] Infants (0-1 year) should receive 400 IU/day, and children aged 1-18 years should receive 600 IU/day; however, although those amounts should be sufficient, the guidelines acknowledged that 1000 IU/day may be needed if trying to maintain a serum 25-hydroxy vitamin D level above 30 ng/mL in those at risk for vitamin D deficiency. In adults aged 19-50 years, 600 IU/day should be adequate for daily activities; however, 1500-2000 IU/day may be necessary in those at risk.

Guidelines for Vitamin D Intake[5]

Age (years)


For Those at Risk for Vitamin D Deficiency

Upper Limit Recommended


400 IU


1000 IU


600 IU

600-1000 IU

4,000-10,000 IU


600 IU

1500-2000 IU

10,000 IU

Upper limits for the amount of vitamin D were also given by age to reduce the chance of achieving vitamin D intoxication, which is characterized by a 25-hydroxy vitamin D level of > 150 ng/mL, which may lead to hypercalcemia and hyperphosphatemia.[10]

Vitamin D levels should be checked in those at risk for vitamin D deficiency. Individuals who should be screened include[6,8]:

  • Children on chronic glucocorticoids, antiepileptic drugs, and antifungal medications

  • Those with chronic diseases that lead to malabsorption

  • Darker-skinned infants who live in higher-latitude areas with a lack of sunshine

  • Those with signs/symptoms of poor growth or irritability that could be due to an electrolyte abnormality

  • Those with frequent fractures

  • Women who are pregnant/lactating

  • Those with elevated alkaline phosphatase level for age

The vitamin D levels for the patient in this case were corrected. PTH and calcium levels within the reference range were observed 3 months after starting vitamin D. He continues to follow up with his primary care physician and consulting endocrinologist to control his type 1 diabetes and Hashimoto thyroiditis.


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