IS GOUT PARTIALLY ABOUT GIRTH?: As more people get the "disease of kings," scientists are trying to parse how gout might be tied to lifestyle--and increasing rates of obesity and hypertension. Image: WIKIMEDIA COMMONS/HELLERHOFF
The "disease of kings" has now reached the masses. In the past half century the prevalence of gout in the general U.S. population has more than doubled. Once thought of only for the privileged few who had the means to overindulge in food and drink, gout now afflicts more than eight million American adults. And research suggests that the rates of this form of localized arthritis are still on the rise.
The new study found that some 3.9 percent of U.S. adults have been diagnosed with gout at some point. Some people have only one or infrequent flare-ups. But others are plagued by chronic, recurring symptoms. And the condition continues to affect men more often than women (some 5.9 percent of men versus 2 percent of women), according to the new analysis, which was published online July 28 in Arthritis & Rheumatism. The researchers also found that, in their study of more than 5,000 people, about 21.4 percent had high levels of uric acid in their blood, which is known to be a risk factor for developing gout.
Much of the evidence points to a link between gout and the increasing prevalence of obesity and hypertension. And as body mass indexes continue to rise worldwide, "it's only going to grow," says Jennifer Hootman, an epidemiologist at the U.S. Centers for Disease Control and Prevention, who was not involved in the new research.
But, researchers say, the condition is also largely preventable, and new medications have made it easier to treat.
A disease of the rich (nations)?
The steady climb of gout rates over the past 50 years comes as no surprise to many researchers. "This is not the first paper" to find the increasing rates of gout, says Allen Anandarajah, an associate professor of medicine and a rheumatologist at the University of Rochester Medical Center, who was not involved in the new research. He says that doctors are probably doing a better job of diagnosing patients, but many people—possibly even the majority who have more episodic gout—do not see their doctors about it at all. Acknowledging that likelihood, he says, the occurrence of gout in the general population might be as high as 10 percent of adults.
Data from global analyses suggest that an increase in gout has not just been limited to the U.S. Along with increasing rates of obesity and hypertension, research has also indicated a rise in gout's prevalence in Europe, Asia and even urban sub-Saharan Africa.
Even though gout rates have been climbing "I don't think it's on people's radar screens," Hootman says. "I really don't think they think about it"—especially that it is so often correlated with larger health problems such as metabolic syndrome, which is a cluster of symptoms that include elevations in blood pressure, cholesterol and body fat.
Anandarajah suggests that the new study is "a timely reminder to all of us," too, to be more attuned to patients—especially those who are older or suffer from obesity, hypertension or diabetes.
For those who have a bout with gout, the experience is not easily forgotten. A build up of uric acid, because of diet, lifestyle, disease or medication, can cause small crystals to form in a joint, leading to inflammation characterized by a swollen red area and intense pain. Gout most commonly manifests itself around the big toe joint, but it can also crop up elsewhere in the foot or in the ankle, knee or other joints.
Chronic cases can also frequently be misdiagnosed. Daniel Mueller, a physician at the University of Minnesota Medical School who treats patients with gout, notes that especially in older adults, the condition can often be mistaken for other joint problems. "And we're going to see more of that as the population gets older," he says.
There's also suggestion that too much uric acid "might contribute to other conditions," such as heart attack, stroke or diabetes, says Hyon Choi, a professor of medicine at the Boston University and co-author of the new study. But given that heart disease and diabetes are also associated with metabolic syndrome—and thus with gout—"it's not completely proven if they're causally linked or just an association," he notes.
And a harmful cycle might be underway. "It could also be that gout feeds back and contributes to obesity and to hypertension," Mueller says. He explains that high levels of uric acid might stimulate the immune system, and that extra activity could lead to chronic inflammation and, eventually, cardiovascular problems. But, he notes, "it's still just a hypothesis."