Nov. 10, 2010 -- ATLANTA — Here in the home of Coca-Cola, researchers reported that consumption of fructose-sweetened sodas was significantly associated with newly diagnosed gout in the Nurses' Health Study.
Participants in the 22-year study who reported drinking one sugary soda per day were 74 percent more likely than those who said they drank less than one per month to develop incident gout – an inflammatory condition caused by elevated levels of uric acid in the blood that deposits in the joints – according to Dr. Hyon Choi of Boston University and colleagues.
The risk was even higher among participants who reported drinking two or more sugary sodas per day, Choi reported at a poster session here during the American College of Rheumatology's annual meeting. The findings were also published simultaneously online in the Journal of the American Medical Association.
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The association was not limited to soft drinks, though — orange juice also appeared to be a risk factor for incident gout.
"Physicians should be aware of the potential effect of these beverages on the risk of gout," Choi and colleagues wrote in the JAMA article.
They noted that, although gout has been a predominantly male disease, it strikes women too, particularly those older than 70.
The Nurses' Health Study, a huge longitudinal study of female health professionals that began in 1984, appeared to be an ideal for examining the role of diet in gout among women. Participants completed a detailed questionnaire on diet and other lifestyle factors at baseline and were followed prospectively through 2006, providing 22 years of follow-up.
Choi and colleagues looked for associations between sugar-sweetened drink intake and incident gout in about 79,000 participants who did not have known gout at baseline. During the study, 778 women were diagnosed with gout.
After adjusting for other dietary factors believed to contribute to gout as well as age, menopause status, body mass index, history of hypertension, diuretic use, and hormone therapy, the researchers found significant correlations between fructose-sweetened soda consumption and incident gout.
Consumption of diet soft drinks at any level examined in the study — the highest category was two or more per day — was not associated with gout incidence.
Looking only at sugar-sweetened cola beverages, participants who drank two or more per day were 97 percent more likely to develop incident gout than those who consumed less than one per month.
An even stronger relationship to gout risk was seen with orange juice consumption. Women who said they drank it once daily were at 41 percent higher risk for a gout diagnosis, rising to 142 percent with twice-daily consumption.
Other fruit juices collectively did not show a significant association.
Choi and colleagues also examined the gout risk associated with fructose consumption from all sources in various study subgroups, stratified by body mass index, alcohol consumption, and low-fat dairy intake. The latter did not seem to affect the gout risk conferred by fructose consumption.
But in women with BMI of 30 or more and those drank alcohol (compared with abstainers), the effects of fructose on gout risk appeared strengthened.
Fructose, unlike other sugars, increases uric acid levels in the blood, Choi and colleagues explained.
In their JAMA report, they cautioned against blowing the risks out of proportion. "Absolute risk differences were modest given the low incidence rate of gout among women," they wrote. Less than one percent of women included in the analysis developed gout during follow-up.
Consequently, the risk difference associated with orange juice, for example, worked out to less than one case per 1,000 person-years, Choi and colleagues noted.
But they also suggested it would be wise for women with diagnosed gout or hyperuricemia to stay away from fructose-sweetened drinks.