Endocrine Abstracts

Vitamin D, vital for overall health beyond its traditional role in bone metabolism, has seen a significant increase in use in recent years, particularly during the COVID-19 pandemic, due to its cited immune-boosting properties. An Irish Longitudinal Study on Aging (TILDA) reported a significant rise in vitamin D supplementation during pandemic, particularly among women (17.3%) compared to men (11.1%). However, this surge in consumption has been accompanied by a rise in cases of vitamin D toxicity. This increase is linked to misuse of over-the-counter supplements or erroneous prescriptions. Vitamin D toxicity leads to hypercalcemia, with symptoms ranging from fatigue to confusion and kidney injury in severe cases. Among cases of toxicity, vitamin D levels > 375 nmol/L have been observed. Hypercalcemia in this context can persist for up to 18 months. Diagnosis requires clinical history, laboratory testing and exclusion of alternative causes of hypercalcemia. We report two cases of hypercalcemia secondary to vitamin D toxicity. The first case involves a 74-year-old male who presented with constipation, polydipsia, fatigue, weight loss and renal impairment. He had been self-administering high-dose vitamin D (10,000IU daily) since the COVID-19 pandemic, leading to confirmed vitamin D toxicity with levels > 375 nmol/L. The second case involves a 73-year-old female who presented with confusion, weight loss, and decreased appetite. Tests revealed vitamin D levels > 375 nmol/L. Both patients had been using excessive over-the-counter vitamin D and calcium supplements, with other causes of hypercalcemia excluded. In the wake of the COVID-19 pandemic, the widespread use of vitamin D supplements increased due to broad recommendations. With high-dose supplements readily available online without prescription, there has been a significant increment in vitamin D toxicity incidence. This observed rise in cases represents a need for education and awareness about potentially dangerous consequences among healthcare providers and the general population.