A study shows that the incidence of gout, a type of arthritis, rose 44% over the past two decades, mostly in men and seniors.

Gout now afflicts 8.3 million Americans, or 3.9% of the population, compared to 6.1 million, or 2.7%, in the late '80s and early '90s. Since the 1960s, the incidence of gout has more than doubled, the study said. It was published in Arthritis & Rheumatism, a journal of the American College of Rheumatology.

Fatter waistlines and hypertension are largely to blame, the study showed—and the risk increases with age. The painful condition is caused when uric acid builds up in the joints, and is associated with metabolic syndrome, which may increase the risk of heart attack and diabetes.

Boston University researchers studied the latest National Health and Nutrition Examination Survey of 5,707 people, conducted in 2007 and 2008, and compared that to comparable statistics from 1988 to 1994.They found that not only was the frequency of gout 1.2% higher than the earlier period, the frequency of elevated uric acid levels, a pre-gout condition, was 3.5% higher, affecting about 43.3 million people.

A Kelton Research study of 1,000 people released earlier this year found that a minority of Americans were unaware of the risk factors for gout, which besides obesity and hypertension include diabetes, kidney disease, excessive alcohol use and a family history of gout. Among the 235 surveyed who had gout, more than half were aware that limiting certain foods and alcohol, losing weight and exercising could help them. But one in five of the gout sufferers said that they don't do anything to manage their disease.