New Zealand scientists have discovered fizzy drinks and fruit juice increase the risk of gout by interfering with a gene that normally helps prevent the disease.
Gout is New Zealand's most common form of arthritis and is most prevalent among Maori and Pacific Island men, more than one in ten of whom have the disease.
Researchers at Otago and Auckland universities found too much fizzy drink or fruit juice affects a variant of a gene that normally helps prevent gout by removing uric acid from the blood.
Tony Merriman of Otago University says his team found that when people consume sugary drinks the gene acts in reverse, adding more uric acid, which forms crystals in people's joints, causing painful inflammation.
The researchers say for every can of fizzy drink a person consumes a day, the risk of gout rises by about 13 percent.
Professor Merriman says an increase in gout in recent years may have been driven by the rise in consumption of sugary drinks.
The team says the gene variant SLC2A9 is carried by about 20% of Europeans and about 10% of Maori and Pacific Islanders.