Vitamin D May Help Protect Against Rheumatoid Arthritis 

More Vitamin D Study Needed, Experts Say

< January 14, 2004 > -- Vitamin D may help protect older women against rheumatoid arthritis, according to a new study reported in the medical journal Arthritis & Rheumatism.

Analyzing data from the Iowa Women's Health study,  researchers looked at a sample of nearly 30,000 women, aged 55 to 69, who did not have rheumatoid arthritis at the study's start.

The researchers followed the women for 11 years, asking them about eating habits, supplement use, smoking history, and body mass index.

Rheumatoid arthritis (RA) is an autoimmune disorder involving inflammation in the lining of the joints and sometimes other internal organs as well. RA is often chronic and painful, and can flare up and then subside.

Rheumatoid arthritis affects 2.1 million Americans, according to the Arthritis Foundation, and onset usually occurs in middle age. About two to three times as many women as men have the disease.

Highest Levels Show Greatest Protection

In the study, the researchers discovered 152 cases of RA in the women during the 11 years of follow-up. And the study results suggest that getting enough vitamin D can reduce the risk.

"If they took in less than 200 international units (IUs) of vitamin D a day, they had roughly a 33 percent increased risk for developing rheumatoid arthritis compared with those who received more than 200 IUs daily," says senior investigator Dr. Kenneth G. Saag, at the University of Alabama at Birmingham.

Four hundred international units of vitamin D a day are recommended, either from foods or supplements.

Exactly why vitamin D may guard against rheumatoid arthritis is not known, Dr. Saag adds. "Vitamin D has its major effect in regulating calcium in the body," he says.

"But we don't think this would necessarily explain this [protective effect] also," Dr. Saag says. "Vitamin D also has effects on the immune system," and it might somehow modulate the immune response that occurs when RA strikes.

Dr. Saag emphasizes that further research will need to be conducted to confirm the link between vitamin D and rheumatoid arthritis.

Meanwhile, he says, "This is just another reason why you need to eat a healthy diet."

It is best to get vitamin D from food, he says.

"If you are getting enough in your diet, great," Dr. Saag says. "If not, you probably need to be supplemented."

A cup of milk has about 100 IUs of vitamin D, and a cup of cornflakes about 40 IUs, according to the American Dietetic Association. The National Institutes of Health (NIH) Clinical Center states that 3 1/2 oz of salmon (cooked) has 360 IUs, 3 1/2 oz  of mackerel (cooked) has 345 IUs, and 3 1/2 oz  of liver or beef (cooked) has 30 IUs.

The NIH does state that there is a high health risk associated with consuming too much vitamin D. Vitamin D toxicity can cause nausea, vomiting, poor appetite, constipation, weakness, and weight loss. It can also raise blood levels of calcium, causing mental status changes such as confusion.

The NIH reports that high blood levels of calcium also can cause heart rhythm abnormalities. Calcinosis, the deposition of calcium and phosphate in soft tissues, such as the kidney, can be caused by vitamin D toxicity.

Additional Routes to Reduce Risk

Dr. John Klippel, president and chief executive officer of the Arthritis Foundation, calls the research results important.

"Vitamin D appears to be protective," Dr. Klippel says, but "I think we need to be cautious in interpreting it" because the results are preliminary. The Arthritis Foundation helped fund the study.

Dr. Klippel says the study is believed to be the first clinical research that has found a potential protective effect from vitamin D against rheumatoid arthritis.

Until more research is in, there are other ways to reduce the risk of RA, Dr. Klippel says.

"Smoking appears to be a risk factor," he says. "Excess caffeine may be a risk factor."

Experts say the earlier a diagnosis is made and treatment is started, the more joint damage and impairment can be prevented. Treatment can range from simple therapies, such as diet and rest, to more aggressive therapies, including medications.

"The longer between diagnosis and treatment, the greater the risk of joint damage and disability," Dr. Klippel says. "See a rheumatologist early and get treated early."

Always consult your physician for more information.

Online Resources

Arthritis Foundation

Centers for Disease Control and Prevention (CDC)

HealthierUS.Gov

National Institute of Arthritis and Musculoskeletal and Skin Diseases

National Institutes of Health (NIH)

National Institutes of Health Clinical Center

US Food and Drug Administration

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Rheumatoid Arthritis Explained

Rheumatoid arthritis, a chronic, autoimmune disease, is the most crippling form of arthritis.

This chronic disease is characterized by painful and stiff joints on both sides of the body that may become enlarged and deformed.

Onset of the disease is usually middle-age, but it does occur in individuals as early as age 20. Patients with rheumatoid arthritis may also have osteoporosis, a progressive deterioration of bone density.

Juvenile rheumatoid arthritis (JRA) is a form of arthritis in children ages 16 or younger that causes inflammation and stiffness of joints for more than six weeks.

Unlike adult rheumatoid arthritis, which is chronic and lasts a lifetime, children often outgrow juvenile rheumatoid arthritis. However, the disease can affect bone development in the growing child.

The exact cause of rheumatoid arthritis is not known. Rheumatoid arthritis is an autoimmune disorder, which means the body's immune system attacks its own healthy cells and tissues.

The response of the body causes inflammation in and around the joints, which then may lead to a destruction of the skeletal system.

Rheumatoid arthritis also may have devastating effects to other organs, such as the heart and lungs. Researchers believe certain factors, including heredity, may contribute to the onset of the disease.

The joints most commonly affected by rheumatoid arthritis are in the hands, wrists, feet, ankles, knees, shoulders, and elbows. The disease typically causes inflammation symmetrically in the body, meaning the same joints are affected on both sides of the body.

Symptoms of rheumatoid arthritis may begin suddenly or gradually.  Symptoms may include:

• inflamed, painful joints
  
  
• stiff joints
  
  
• enlarged and/or deformed joints (such as fingers bent toward the little finger and/or swollen wrists)
  
  
• frozen joints (joints that freeze in one position)
  
  
• cysts behind the knees that may rupture, causing lower leg swelling and pain
  
  
• hard nodules (bumps) under the skin near affected joints
  
  
• low-grade fever
  
  
• inflamed blood vessels (vasculitis) may occur occasionally, leading to nerve damage and leg sores
  
  
• inflamed membranes around the lungs (pleurisy), the sac around the heart (pericarditis), or inflammation and scarring of the lungs themselves, that may lead to chest pain, difficulty breathing, and abnormal heart function
  
  
• swollen lymph nodes
  
  
• Sjögren's syndrome (dry eyes and mouth)
  
  
• eye inflammation
  

Always consult your physician for a diagnosis.