People who drink many cups of coffee every day appear to be at a higher risk of developing rheumatoid arthritis. Those who drank four or more cups of coffee a day had twice the risk of developing rheumatoid arthritis, compared with people who drank less coffee.

Rheumatoid arthritis is an autoimmune disease in which the body's defenses attack its own tissues. It is more common in women, tends to strike between the ages of 36 and 50, and results in a chronic destruction and deformity of the joints. Smoking, high cholesterol, being overweight and certain dietary factors have also been linked with a higher risk of the disease.

Dr. Maarku Heliovaara of the National Public Health Institute in Helsinki and colleagues looked at data from nearly 19,000 healthy men and women who entered a study in the early 1970s and were followed for 15 years.

In that time, 126 people developed rheumatoid arthritis and 89 of those people had detectable levels of rheumatoid factor -- an antibody that is often found in the blood years before the onset of rheumatoid arthritis.

Coffee drinkers were at higher risk of developing rheumatoid factor-associated rheumatoid arthritis.

The results "should be viewed as the first step in support of the hypothesis that coffee consumption has a causative role in the development of rheumatoid factor positive rheumatoid arthritis," the researchers write. It is not clear why coffee might be associated with rheumatoid factor.

Most people in the current study drank boiled coffee, a practice no longer common in Finland. It is possible that some ingredient in coffee that is associated with rheumatoid factor is removed by the filtration, according to the researchers.

"In Finland, more than three quarters of coffee consumers have switched from boiled coffee to filtered coffee since the 1970s," according to the report. "The type of coffee consumed should therefore be considered in further studies on the relation between coffee and rheumatoid arthritis," the researchers write.

Currently rheumatoid arthritis affects more than two million people in the US, according to the American College of Rheumatology.

Annals of the Rheumatic Diseases 2000;59;631-635.

Dr. Mercola's Comments:

Coffee is not the healthiest liquid to drink, but compared to soda and juice it is health nectar. Ideally, you should avoid it. However, it is far less toxic than the sugar-laden drinks like soda. Part of the reason coffee is a problem is that most of it is not grown organically, and it is one of the most highly sprayed pesticide crops. Much of it is also grown in foreign countries, which have far fewer restrictions than the United States. So if you are going to drink coffee, I would strongly suggest limiting it to organic varieties only.