A new study raises the possibility that people who drink a lot of coffee might be more likely to develop rheumatoid arthritis. A Finnish study, published this past week in the British Medical Association found that people who drank more than three cups a day had twice the chance of getting the disease as those who drank less. While the study does not prove drinking coffee causes rheumatoid arthritis, it is the first to produce evidence of a possible link.
Scientists do not know what causes rheumatoid arthritis but recent studies have raised suspicions about smoking and obesity. Rheumatoid arthritis occurs when the immune system goes awry and attacks the joints, causing inflammation, pain and stiffness.
The new study followed the coffee drinking habits of 19,000 Finnish people over 15 years. None had rheumatoid arthritis when the study began in the 1970s. By 1989, 0.5 percent of those who drank more than three cups of coffee developed rheumatoid arthritis. About 0.2 percent of the people who drank three cups of coffee a day or less got the disease.
The researchers hypothesized that some unidentified ingredient in coffee may trigger the production of rheumatoid factor, an antibody that can be detected in the blood years before the onset of arthritis. Because the Finnish people are heavy coffee drinkers, there weren't enough nondrinkers to make a comparison that might show how important a role coffee drinking might be.
The study researchers said it was impossible to tell whether one type of coffee could be worse than another, but that the effect might be linked to the way the Finns prepared the coffee. They noted that boiled coffee was popular in Scandinavia until filtered coffee became dominant in the 1980s. Boiled coffee, which is made by boiling coffee grounds in a pot then leaving them on low heat all day, gets more concentrated as the day wears on. If the effect of coffee on joints proves real, it may be because the coffee was boiled.
Some experts are skeptical of the study's conclusions and ask why Finland doesn't have a higher prevalence of rheumatoid arthritis than other countries if it has a high rate of coffee drinking. About 1 percent of Finns get rheumatoid arthritis -- a similar rate to other nationalities. Until more studies are able to find a link between coffee and arthritis, you might want to stick to no more than 3 small (6 ounce) cups of unfiltered coffee per day (LB).
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