She didn't always order the test. For more than two decades in private practice, in fact, Dr. Patricia Czapp almost never checked the vitamin D levels of her patients.
Things have certainly changed.
"For the last two years, I've been testing virtually all of my patients," said Czapp, a family doctor at Annapolis Primary Care. "The vast majority are straight-out deficient or insufficient. It's frightening to think there's that many people walking around with that deficiency."
What doctors are beginning to understand is that vitamin D isn't just important for absorbing calcium and building bones. And new research seems to be coming out by the day suggesting vitamin D deficiency can lead not just to osteoporosis but possibly to heart disease, multiple sclerosis, diabetes, even cancer. Vitamin D is believed to impact the immune system and, one researcher suggests, perhaps even the functioning of the brain.
"When you start reading about vitamin D, how can you not offer that to your patients?" said Czapp, who was persuaded by a newly trained colleague to check for deficiencies. "What we're coming to find out is most of the cells in the body have a vitamin D receptor. Vitamin D touches hundreds of different genes in the body, regulating the immune system, fighting infection, cancer cells."
She isn't the only physician ordering more vitamin D tests. She is part of a growing trend among doctors turning the once-rare test into a routine part of the annual physical, making it one of the top five blood tests ordered nationwide, according to two leading lab companies.
Patients, reading recent headlines about vitamin D or hearing about it on the news, are also pushing the popularity of the test, asking their doctors about a vitamin they rarely thought about before. One grass-roots health organization is advocating that everyone have their vitamin D levels checked.
All this comes as the American Academy of Pediatrics doubled its recommendation last month of how much vitamin D children should take daily and as other groups are pushing for adults to get up to 10 times more than is currently recommended in their diets.
As many as half of Americans, middle-age and older, are believed to get an inadequate amount of vitamin D.
"That's quite sobering and it really says we've got to do better with vitamin D nutrition," said Dr. Anthony W. Norman, a biochemist at the University of California, Riverside who has studied vitamin D for decades.
It isn't easy to get enough vitamin D in the diet. It is found in fortified milk, juice and cereals as well as oily fish such as mackerel, sardines and wild salmon.
Vitamin D is commonly referred to as the sunshine vitamin, because our bodies make it when we are exposed to the sun. In northern climes, however, the sun isn't strong enough in the winter months. In the summer months, just 10 to 15 minutes a day would provide enough vitamin D, but fear of skin cancer means many people are wearing sunscreen when they go out, which blocks the beneficial rays.
Many people get their vitamin D from supplements.
Vitamin D levels are checked by taking a patient's blood and testing for the level of 25-hydroxy vitamin D circulating in it. More than 30 nanograms per milliliter is generally considered a healthy level of vitamin D, and any less than 20 is considered deficient.
At the North Carolina-based LabCorp, spokesman Eric Lindblom said the vitamin D test is "one of our fastest-growing tests" and that the number ordered has not only doubled this year, but each of the last four years. At New Jersey-based Quest Diagnostics, the total number of tests has grown "by approximately 80 percent compared to last year," said spokeswoman Wendy Bost.
In September, Mount Washington resident Shannon Wollman had a routine physical and, for the first time, her vitamin D level was checked.
"Everything about my blood work was perfect," she said, "except for the vitamin D deficiency."
Her doctor at Sinai Hospital in Baltimore put her on a serious regimen of vitamin D - one prescription pill of 50,000 international units a week for eight weeks to be followed by an over-the-counter vitamin D dose of about 1,000 IU every day.
Wollman, who works as a major gifts officer in Sinai's development office and as an actress and singer, said she had never thought much about vitamin D until she was given those results. Then, she said, she brought it up with one of her friends at a Rosh Hashana dinner.
"She said, 'The exact same thing happened to me and now I'm on a prescription,'" said Wollman, 40. "It's more common than you realize, and people hadn't been discussing it.
"This was never something I paid any attention to, and now I take it every day."
While 2,000 IU a day has long been considered the upper limit of what is safe, 200 IU a day is what has been recommended for people younger than 50, 400 IU for those 50 to 70 and 600 IU for those older than 70. Norman and a group of other University of California researchers are pushing to increase the government's recommended daily intake to 2,000 IU. And the American Medical Association has asked the Institute of Medicine to review and update its recommendation.
Dr. Jennifer Caudle, an internist at Sinai, has read the new research, but she cautions that people shouldn't just run out and take more vitamin D without first discussing it with their doctors. The enthusiasm and hype for vitamin D now must be tempered until more is known. She said not enough is known about what would happen if someone took too much.
"Is vitamin D important for people? Sure," she said. But, she said, "the information is still being gathered. I'm not sure there's a consensus on exactly how much we should be taking."
Norman says he takes 2,000 IU a day. He said vitamin D has receptors in more than 36 organs in the body, meaning a deficiency causes those organs not to work as well as they could. What he knows now tells him "this is the real deal."
"There's no reason to wait for all this evidence-based research," he said. "You don't want to go a whole decade only being one-half vitamin D supplemented or one-third vitamin D supplemented. You'll be a much healthier person."
At her Annapolis practice, Czapp is thinking about no longer testing all of her patients and telling them they need vitamin D supplements. The test can be expensive - $260, she said - and she sees health-care costs rising. But she worries her patients won't start upping their vitamin D intake unless they have the negative test results in their hands.
Meanwhile, she and her colleagues were spending so many hours explaining to patients what the deficiency was and what they should do to treat it that they came up with a form letter and a protocol to send to people when their results come in.
"We got tired of saying it," she said. "It was easier to hand out a letter that explained all of this."
Carole Baggerly started a group called Grass- rootsHealth last year in California, which focuses solely on promoting information about vitamin D. She started it after a bout with breast cancer that was followed by a diagnosis of osteoporosis. She learned she was vitamin D deficient.
This led to a whole list of discoveries about vitamin D. She read research that suggested raising vitamin D levels may prevent up to half of all breast cancer and two-thirds of colorectal cancer cases in the United States. She read a study showing women with the lowest levels of vitamin D had nearly double the risk of their breast cancer progressing, and a 73 percent greater risk of death compared to women with adequate vitamin D. She found out that the first study linking colorectal cancer and vitamin D was published in 1941.
"It's been an ignored thing," she said. "There's a tremendous disbelief that the problem exists."
Now she spreads the word however she can. She recently held a seminar with 160 doctors discussing the virtues of vitamin D - and the real health advances that she says could be made if everyone got their levels up. She advocates for vitamin D levels between 40 and 60 ng/ml - higher than what is currently considered adequate.
She traveled to many cities over the summer talking about vitamin D.
"The biggest question I got," Baggerly said, "was: 'How do I get my doctor to order the test? He said, 'Oh you don't need it. You're outside a lot.' The statistics say the doctors are wrong."
how to get enough vitamin d
Vitamin D is not found in a lot of foods, so it may be difficult to get all you need in your diet. Vitamin D can be found in:
Foods: Milk, juice and cereals are fortified with vitamin D. It occurs naturally in oily fish such as mackerel, sardines and wild salmon.
Supplements: Many doctors are now recommending patients take over-the-counter supplements.
Sun: In warmer climes and in the summer, people can get enough vitamin D, also called the "sunshine vitamin," from 10 to 15 minutes in the sun in the middle of the day, but only if their skin is not covered with sunscreen. The rays needed to become vitamin D cannot get through sunscreen's barrier.