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A new study has found that sleep apnea is associated with an increased risk for gout, a painful disease of the big toe and other joints caused by elevated levels of uric acid in the blood.

Observational studies have shown that people with sleep apnea have a higher prevalence of excess uric acid, but until now it has been unclear whether sleep apnea is associated with gout, and how strongly.

Using records in a British health database, researchers studied 9,865 people, average age 54, with sleep apnea and matched them to 43,598 controls without the disorder. Because sleep apnea is associated with being overweight, the participants were matched for B.M.I., among many other characteristics. The study is in Arthritis & Rheumatology.

After one year, compared with controls, people with sleep apnea were about 50 percent more likely to have had an attack of gout, and the increased risk was found without regard to sex, age or obesity.

The conclusion suggests that treating sleep apnea would reduce gout attacks, but the lead author, Yuqing Zhang, a professor of medicine at Boston University, is cautious.

“Our findings call for future studies to evaluate the effect of treating sleep apnea on serum uric acid levels and the risk of gout,” he said.