Consumption of two more servings of sugar-sweetened soft drink a day raised the risk of gout in men by 85 per cent, compared to men who drank one serving or less per month, states the research published in the British Medical Journal .
The study may increase attention on the health implications of soft drinks, already in the spotlight regarding the ongoing obesity epidemic.
"Our findings provide prospective evidence that consumption of sugar sweetened soft drinks and fructose is strongly associated with an increased risk of gout," wrote Hyon Choi from the University of British Columbia, and Gary Curhan from Brigham and Women's Hospital, Harvard Medical School.
"Furthermore, fructose rich fruits and fruit juices may also increase the risk.
In contrast, diet soft drinks were not associated with the risk of gout."
Gout is a joint disease which causes extreme pain and swelling.
It is most common in men aged 40 and older.
It is caused by excess uric acid in the blood (hyperuricaemia) which leads to uric acid crystals collecting around the joints.
According to background information in the article, levels of gout have doubled over the last few decades in the US, which has coincided with a substantial increase in the consumption of soft drinks and fructose, state Choi and Curhan.
The researchers analysed the intake of soft drinks and fructose for 46,393 men using validated food frequency questionnaires.
Then men were free of gout at the start of the study.
After 12 years of follow-up, 755 incident cases of gout were documented.
Choi and Curhan report that an increased consumption of sugar-sweetened soft drinks was positively associated with the risk of gout.
Indeed, five to six servings per week were associated with a 29 per cent increase in the risk of gout, while one serving per day was associated with a 45 per cent increase in risk, compared to less than one serving per month.
Two or more servings per day increased the risk to 85 per cent, added the researchers.
On the other hand, no association between gout and diet soft drinks was observed.
When they focussed on fructose intake, a positive link was again observed, with a 41, 84 and 102 per cent increase calculated when free fructose provided 4.5 to 5.3, 5.4 to 6.6, and more than 6.6 per cent of energy, respectively.
Choi and Curhan also report that fruit juice or fructose rich fruits (apples and oranges) were linked to a higher risk of gout "Interestingly, fructose shares ethanol's urate raising mechanism that induces uric acid production by increasing ATP degradation to AMP, a precursor of uric acid," wrote the researchers.
"Fructose phosphorylation in the liver uses ATP, and the accompanying phosphate depletion limits regeneration of ATP from ADP, which in turn serves as substrate for the catabolic pathway to uric acid formation."
The researchers added that, while gout was linked to fruit intake, numerous studies have reported that increased intake of fruit may improve cardiovascular health, and reduce the risk of certain diseases such as certain types of cancer, and age related macular degeneration.
"These various benefits and risks associated with individual fructose rich food items should be carefully considered in the potential public health applications of our findings," they stated.
Commenting independently on the research, Dr Andrew Bamji, president of the British Society for Rheumatology said: "Anecdotally cases of gout appeared to be rising.
When you think about it, the finding that soft drinks consumption may be a cause makes a lot of sense in that fructose raises the level of uric acid in the blood".
"I always tell people to avoid yeast- containing foods - beer and Marmite are two such.
However I will certainly adapt my advice to patients as I suspect the number drinking fructose-containing drinks is quite large".
British Soft Drinks Association were quick to respond to the study, stating: "The leading research in this field does not support the notion that gout is caused by either soft drinks or fruit juice consumption.
"The strongest risk factor for developing gout is family history yet this was not taken into account in the research.
"Neither the National Institute of Health nor the National Institute for Arthritis and Musculoskeletal and Skin Diseases in the USA, where this study was conducted, implicate fructose as a causal risk factor for gout.
"Research conducted on gout over the last century shows that it is foods and beverages that are high in purines, (such as alcohol, and certain meats) that are more strongly linked to uric acid metabolism, which causes gout.
"Soft drinks do not contain purines and scientific studies have shown that neither sucrose nor high fructose corn syrup affect uric acid excretion."
The study was funded by the National Institutes of Health and TAP Pharmaceuticals.
Source: British Medical Journal Published online ahead of print, Online First , doi:10.1136/bmj.39449.819271.BE "Soft drinks, fructose consumption, and the risk of gout in men: prospective cohort study" Authors: H.K. Choi, G. Curhan