Men who consume large amounts of fizzy or sugary drinks are at higher risk of contracting gout than those who abstain, a new study has concluded.

Researchers from Harvard and the University of Vancouver found that those who consumed five or six sweet beverages a week were nearly 30% more likely to suffer attacks of the illness than those who drank less than one serving monthly. The risk rose to 85% for those drinking two or more a day.

As well as sugar in drinks, the study found that natural fruit sugar, or fructose, posed a substantial risk for gout.

That means people who drank orange or apple juice or even ate those fruit regularly were prone to the illness. Meanwhile, diet soft drinks, which often contain sweetener rather than fructose, were not found to be associated with gout.

"The risk of gout was about twice as high among men in the highest fifth of free fructose consumption than among men in the lowest fifth… the current study provides prospective evidence that fructose and fructose-rich foods are important risk factors in the primary prevention of gout in men."

Hyon K Choi and Gary Curham surveyed over 46,000 male medical professionals aged 45-70 with no history of the illness over a period of 12 years, as part of a wider study into diet and general health. A total of 755 reported incidents of the condition. The link between gout and sugary drinks and fructose remained even when accounting for age, alcohol consumption, body mass and high blood pressure.

Gout is caused by a build-up of uric acid in the bloodstream and can cause joint swelling, inflammation and acute pain in the extremities. Uric acid is produced by the kidneys and digestive system from purines, which normally occur in rich food, meat and beer. Women are less likely to suffer from the condition.

Fructose is often used as a substitute for sugar, especially in high-fructose corn syrup, which is cheaper than cane sugar. It is a common ingredient in fizzy drinks. The risk is such that researchers caution that patients who switch from purine-rich food to improve their gout could in fact make it worse if they start eating large amounts of fructose.

The study is published in the latest edition of the British Medical Journal.