Gout is on the rise and fructose-sweetened drinks may be the reason, according to a new study.

Gout causes excruciating pain and swelling in joints, especially in the big toe. Most common in men over 40, it is caused by too much uric acid in the blood. Gout is diet-related; large amounts of uric acid are produced when the body digests substances called purines, which are found in meat, especially internal organs such as liver and kidney, and some oily fish.

In the United States, the incidence of gout has doubled in recent decades. This rise coincides with a substantial increase in the consumption of soft drinks and other drinks sweetened with fructose, the only carbohydrate known to increase uric acid levels.

Those at risk for gout are generally told to restrict their intake of purines and alcohol.

Researchers, led by Hyon Choi, associate professor of medicine at Vancouver's Arthritis Research Center of Canada, and Gary Curhan, associate professor of medicine at Brigham and Women's Hospital in Boston, decided to examine the relationship between drinks containing fructose and the risk of gout. They followed over 46,000 men aged 40 years and over with no history of gout. The men completed regular questionnaires on their intake of more than 130 foods and beverages, including soft drinks and diet soft drinks, over a period of 12 years. The findings appear in the February issue of the British Medical Journal.

During those 12 years, the researchers documented 755 new cases of gout. The risk of gout was a dramatic 85% higher among men who consumed two or more servings of fructose-sweetened soft drinks, compared to those who consumed less than one serving a month. Diet soft drinks were not associated with a higher risk of gout.