February 4, 2011
Low White Blood Cell Count Not Always a Sign of Medical Problem
February 4, 2011
Dear Mayo Clinic:
I was told after my recent physical that my white blood cell count was low. Is this something to be concerned about? Am I more susceptible to catch colds or viruses?
Answer:
A low white blood cell count can sometimes be a sign
of an underlying medical problem, but not always. First, it's important to determine what your health care provider means by "low." Not all medical laboratories use the same range to decide what's normal and what's not. Second, you need to consider factors such as your age, gender and ethnic group. Some groups of people just have naturally lower white blood cell levels than others. If your white blood cell count is truly lower than it should be, then further investigation is warranted to uncover
the root cause.
As part of your immune system, white blood cells fight disease and are important for the body's defense against infections. A chronically low white blood cell count (leukopenia) can make you vulnerable to bacterial infections and could signal a serious health problem. Before you start investigating the cause of a low white blood cell count, though, it's important to discuss with your doctor what your test results mean
Different laboratories classify low white blood cell counts differently. Generally, a count lower than 3,500 white blood cells per microliter of blood is considered a low white blood cell count. But ask your doctor what the normal range is for the laboratory he or she uses. It may also be helpful to discuss exactly how far outside that range your number falls. A white blood cell count that is just slightly below the cutoff for the established normal range may actually still be normal and not require further evaluation.
In addition, what would be considered a low white blood cell count for some people may be a normal finding for others. For example, African-Americans tend to have lower white blood cell counts than Caucasians. It's also not uncommon for young Caucasian women to have white blood cell counts that fall slightly below the normal reference ranges. Talk to your doctor about how individual factors may affect your white blood cell levels.
With all that in mind, if you and your doctor determine that your white blood cell count is lower than it should be, that is cause for concern. Because a low white blood cell count cannot, in and of itself, be used to diagnose a specific disease or disorder, you'll likely need more testing to further assess your condition. Underlying causes for a low white blood cell count can range from benign disorders, such as vitamin deficiencies, to more serious blood diseases, such as leukemia or lymphoma.
A truly low white blood cell count also puts you at higher risk for infections — typically bacterial infections. But viral infections also may be a concern. To help reduce your infection risk, your doctor may suggest you wear a face mask and avoid anyone with a cold or other illness. Washing your hands regularly and thoroughly can also help reduce risk. Ask your doctor if there are other precautions you should take to help avoid infections.
— Rajiv Pruthi, M.B.B.S., Hematology, Mayo Clinic, Rochester, Minn.
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More and more studies are revealing the benefits of having plenty of D—and the dangers of having too little. Use this comprehensive guide to make sure you're getting the amounts you need.
For decades vitamin D's claim to fame was its role as calcium's trusty escort, helping our bones absorb the essential mineral. But a recent flood of research is revealing that D does much more: "There is a vitamin D receptor on every one of our cells," says Michael F. Holick, PhD, MD, author of The Vitamin D Solution. "And those receptors are there for a reason." Actually, many reasons—all of our bodily functions seem to rely on the nutrient, and studies show that it's key to helping prevent everything from migraines to cancer.
The trouble is, most of us—53 percent of women, 41 percent of men, and 61 percent of kids—have insufficient levels. Though our bodies naturally produce the vitamin from the sun's UV-B rays, these days we don't absorb nearly enough sunlight to manufacture an adequate amount—and during winter, most of the country gets so little sun, doing so is impossible. But don't sweat it: With a few easy moves, you can boost your D levels. We've gathered the latest info on the vitamin everyone's suddenly talking about.
High levels of vitamin D are linked to...
High levels are linked to...
Greater resistance to viruses
During a recent study, researchers
at the Yale University School of Medicine discovered that people with high levels of vitamin D got sick about half as often as people with low levels. And when they did fall ill, they recovered in fewer days. The reason: Vitamin D instructs your white blood cells to manufacture a protein that kills infections.
Less cancer
Specifically, a 30 to 50 percent lower chance of breast cancer, and a 50 percent lower chance of colon cancer. D regulates some of the genes responsible for
cellular growth and survival, says Holick, and it does its job cleverly: "It helps shut down any out-of-control growth to prevent malignancy. If that doesn't work, it will help kill the cell. And if a tumor grows anyway, it will work to cut off blood supply."
Higher cancer survival rate
At the Dana-Farber Cancer Institute, researchers found that colon cancer patients with high levels of D had a 39 percent lower chance of dying from the disease. And this might actually apply to
all cancers, says Edward Giovannucci, MD, ScD, professor of nutrition and epidemiology at the Harvard School of Public Health.
Reduced risk of Parkinson's
Researchers believe the correlation, which Archives of Neurology reported in July, may have to do with D's protective effect on the brain: It regulates calcium levels, enhances the conduction of electricity through neurons, and detoxifies cells, among other handy functions.
Low levels are linked to...
Low levels are linked to...
Heart disease
People with insufficient D levels have an 80 percent greater risk of narrowing of the arteries, according to a long-term study at Johns Hopkins. This might have to do with D's role in regulating more than 200 genes and controlling inflammation, and its possible involvement in
modulating blood pressure.
Diabetes
Since D stimulates insulin production, it's no surprise that too little is associated with diabetes. Research has also shown that kids who are deficient in D have a 200 percent greater chance of developing type 1.
Chronic pain
A 2008 study showed that more than 25 percent of chronic pain patients have low D levels, which could be because D helps control neuromuscular function. And a 2010 study correlated low levels of the
vitamin with migraines and headaches. A dearth of D may prevent blood vessels from constricting and dilating properly, which can lead to throbbing pain.
Depression
D may help stimulate serotonin production, which could explain why people who don't get enough are more susceptible to the blues.
Higher risk of death
After analyzing D levels of more than 13,000 people, researchers at Johns Hopkins found that those with the lowest levels had a 26 percent greater
chance of dying—from any cause.
Next: 5 things that increase your risk of vitamin D deficiency
From the November 2010 issue of O, The Oprah Magazine