Sunbed users have 90 percent higher vitamin D blood levels than the general population, according to a Boston University study. But chances are, most don’t actually know what their vitamin D level is. Do you?

“Vitamin D is ‘The Sunshine Vitamin’ — it makes sense for those who believe in regular sun exposure to know their vitamin D levels and to be able to tell your friends, family and community what your level is,” Smart Tan Vice President Joseph Levy said. “My last vitamin D blood test showed my vitamin D level is 46 ng/ml. It’s been as high as 52 ng/ml before.”

The BU study — published in the American Journal of Clinical Nutrition — showed that sunbed users on average have vitamin D levels between 40-50 ng/ml. The general population, on average, is in the mid-20s.

Another study from the University of Alberta last year showed that sunbed users, as a group, have the highest vitamin D levels in Canada. That’s because full-body UV exposure, in non-burning dosages, can make up to 10,000 – 20,000 IU of vitamin D naturally in the skin — 100-200 times more than is fortified into an 8-ounce glass of whole milk.

Who has the lowest vitamin D levels?

An Australian study published in the British Journal of Dermatology showed that dermatologists at the end of summer — when their vitamin D levels should be their highest — had levels less than 14 ng/ml on average. That’s deficient by anyone’s definition and is borderline for severe deficiency.

NBC News Washington bureau in March did a story about a Washington, D.C., dermatologist whose son had severe vitamin D deficiency. Click here to see that report.