Each morning, across America, women rev up their engines by downing a cup of caffeine-rich coffee. A few buck the trend, preparing instead a cup of tea. And some of the more health conscious choose a decaf brew. But for the vast majority, no morning beverage offers the appeal of a strong cup of regular java.
Data from a pair of large studies reported in November at the American College of Rheumatology meeting in San Francisco now suggest that a womans choice of brew may affect her joints.
The good news for coffee lovers: Both new studies find that caffeine poses no problem. Regular consumption of decaffeinated brews, however, in each study raised a womans risk of developing rheumatoid arthritis. This autoimmune disease produces crippling pain while ravaging joints.
Beyond that, the studies appear to contradict not only each other but also another study published last year.
For scientists, the divergent findings merely provide a call for more research. Perhaps the researchers asked their subjects imprecise questions. Perhaps the subjects answered dietary questions inaccurately. Or perhaps other, yet-unidentified factors influence whether and how these warm drinks affect immune reactions in the joints.
For consumers, these unresolved issues mean that the jury remains out on whether its smart to substitute one morning brew for another.
In Iowa . . .
Rheumatologist Ted R. Mikuls of the University of Alabama-Birmingham and his colleagues reported on a survey of more than 31,000 women between the ages of 55 and 69. All were part of the ongoing Iowa Womens Health Study.
Over the first 11 years of the study, which began in 1986, 158 of the volunteers were diagnosed with rheumatoid arthritis. By comparing dietary and other habits as reported in questionnaires at the start of the study, Mikuls group obtained clear evidence that drinking four or more cups of decaffeinated coffee daily increased a womans risk of developing the autoimmune disease. After accounting for other known risk factors, such a decaf habit appeared to more than double a womans risk.
Drinking regular coffee, in any amount, showed no effect. Indeed, Mikuls notes that even after accounting for all other sources of caffeine in the diet, we could find absolutely no association between caffeine and rheumatoid arthritis. So, our take is that its not the caffeine–or lack of it–thats driving risk.
And tea drinkers? They appeared to derive a benefit. Though there were only nine tea drinkers among the group of women who developed the disease, their choice of brew appeared–after accounting for other arthritis risks–to cut their risk of developing this autoimmune disease by 60 percent.
That would seem to make sense, Mikuls says, because tea contains a host of antioxidant-rich plant pigments known as polyphenols. In other studies, these compounds quashed the joint-damaging immune reactions present in animals suffering from a condition that mimics human rheumatoid arthritis (SN: 4/17/99, p. 247).
Further support for that idea emerged in a second analysis of the Iowa women that Mikuls team reported at the meeting. Here, they analyzed consumption of antioxidant vitamins. The data showed that women who consumed the most vitamin C and supplemental vitamin E had a reduced risk of elderly-onset rheumatoid arthritis.
but in Boston . . .
Most studies of rheumatoid arthritis have been conducted in white populations–even though the disease is an important source of pain and disability in black women. So in a study of 64,000 black women that began 6 years ago, Timothy E. McAlindon of the Boston University School of Medicine and his colleagues investigated dietary factors affecting risk.
At the rheumatology meeting, McAlilndons team also reported finding that decaffeinated coffee increased risk. Drinking at least a cup a day quadrupled the chance of developing the disease, while drinking regular coffee did nothing. More confusing: Women who drank at least a cup of tea a day faced double the risk of developing rheumatoid arthritis seen in women who eschewed this brew.
and in Finland . . .
Both of the new U.S. studies follow hot on the heels of a Finnish one, reported last year. In it, Markku Heliövaara of the National Public Health Institute in Helsinki and his colleagues made the initial link between coffee consumption and risk of rheumatoid arthritis.
In sharp contrast to the two new investigations, the Finnish one, which studied nearly 19,000 men and women over a 16-year period, linked increased risk to consumption of four or more cups of caffeinated coffee. Explains Heliövaara, few people in his country drink decaf–and fewer still drink tea.
Heliövaaras team linked coffee consumption with a doubled risk of developing rheumatoid arthritis, but only in persons who also had blood markers of an antibody known as rheumatoid factor. Observes Mikuls, somewhere between 60 and 80 percent of rheumatoid arthritis patients will have this factor in their blood. However, many healthy people also have this blood marker. As such, Mikuls notes, its precise role in predisposing or causing rheumatoid arthritis remains muddy.
Sorting through the findings
Why might regular coffee pose a risk in the Finnish population but not in the U.S. ones?
Heliövaara says he doesnt know, but he does point out that most of the people in his population previously drank boiled coffee. The brewing technique permitted much of the cholesterol-raising oils in the coffee beans to end up in the drink. By contrast, brewing coffee in a drip system that employs a filter–as most people in the United States and even todays Finns do–eliminates virtually all of the cholesterol-raising oils (SN: 2/4/95, p. 72).
As such, Heliövaara concedes, the apparent link to regular coffee in his population may actually reflect heavy previous consumption of the boiled brew. That should sort itself out in a new study of 8,000 Finns whom his team has just surveyed–many of whom started coffee drinking after the mid-1970s, when the Scandinavian preference for boiled coffee began to fade out.
Mikuls says that hes also heard that decaffeinating techniques have changed in recent years–which may mean that the risks hes seeing in older Iowa women may trace to a processing method no longer in use. If true, he says that todays decaf might be safe for joints.
Heliövaara admits to drinking four or more cups of java daily. But even if a link to some type of coffee remains, he suspects that it will not erode the market for this drink.
After all, he notes, its not linked to premature mortality. Its not linked to cancer or coronary heart disease. If the only danger from coffee were to prove to be the development of rheumatoid arthritis–a relatively rare condition–there would be no general need to recommend against drinking it."
National Public Health Institute
Ted R. Mikuls
Division of Clinical Immunology and Rheumatology
University of Alabama, Birmingham
1530 3rd Avenue North
Birmingham, AL 35294