At the end of May, the US Food and Drug Adminisitration ordered tanning bed manufacturers to post warnings on their products that they should not be used by teens under the age of 18, citing concerns about skin burns and increased risks of melanoma, the deadliest type of skin cancer. But there’s apparently another danger associated with excessive use of tanning beds: vitamin D toxicity. In a report last Monday in the Annals of Internal Medicine, two physicians from Saint Vincent Hospital in Worcester described a 26-year-old woman treated for excessively high vitamin D levels detected during a routine blood test. At first, the physicians couldn’t pinpoint the cause because the woman didn’t take vitamin D supplements and wasn’t a big milk drinker. She did, however, go to a tanning salon at least three times a week for six months. The ultraviolet radiation from the UV lamps caused her skin to produce vitamin D in excessive amounts.
Dangerously high vitamin D levels, called hypervitaminosis D, can damage bones, joint tissue, and kidneys. It’s also associated with a wide range of symptoms, including vomiting, constipation, dehydration, fatigue, and muscle weakness.
“Other such cases have not been reported to our knowledge,” wrote the report authors, “and we alert clinicians that patients who use tanning beds may have elevated vitamin D levels.”