A new study finds that drinking orange juice, soda and other beverages high in the sugar fructose could increase the small risk that middle-age and elderly women have of developing gout. Gout is a painful form of arthritis caused by too much uric acid in the blood. For women in the study who drank two or more servings of these beverages per day, the risk of gout was more than double that for women who drank sugary sodas and juices less than once per month. Because gout is relatively rare among women, the drinks probably contribute only moderately to a woman's chances of developing it. Still, this is the first study linking sodas and sweetened fruit juices to women's gout risk. Previous research found such a link for men.
The study will be published in the Nov. 24 issue of the Journal of the American Medical Association, and is being presented today (Nov. 10) at the American College of Rheumatology annual scientific meeting.
Gout occurs when levels of uric acid in the blood become too high, and uric acid crystallizes around the joints, leading to inflammation, swelling and pain. Foods than can increase the levels of uric acid in the blood include organ meats (such as kidneys and livers), asparagus and mushrooms, according to the Mayo Clinic. Fructose is also known to increase blood uric acid levels, the researchers said. While gout is not common in the United States, the rate of incidences has more than doubled over a 20-year period, from 16 cases per 100,000 Americans in 1977 to 42 per 100,000 in 1996. Over this period, the researchers noted, the population also consumed increasing amounts of soda and other drinks sweetened with fructose.
The new study followed 78,906 women for 22 years, from 1984 to 2006, as part of the Nurses' Health Study. At the beginning of the study, none of the women had gout. By the end, 778 had developed it. Women who drank one serving of soda per day were 1.74 times more likely to develop gout than those who drank less than one serving per month. Those who drank two or more servings per day were 2.4 times more likely to develop gout. Drinking two or more servings of soda per day caused an additional 68 cases of gout per 100,000 women per year, compared with drinking less than one serving of soda per month, the researchers said. Drinking orange juice also increased the risk. Women who drank one serving of orange juice per day were 1.41 times more likely to develop gout, and those who drank two or more servings were 2.4 times more likely to report gout.
Lifestyle and diet
The rise in gout cases is most likely due to changes in lifestyle and diet and an increase in conditions associated with gout, such as metabolic syndrome, said study researcher Dr. Hyon K. Choi of the Boston University School of Medicine. The results held even after the researchers took into account factors that could have influenced the findings, such as age, body mass index and whether the women had gone through menopause, Choi said.
The findings suggest diets to prevent gout should reduce fructose intake, the researchers said.
The study was funded by the National Institutes of Health.
Professor Latz has recently been recruited by the University of Bonn after working ten years in basic research in the United States. Here, he heads the new Institute for Innate Immunity (Institut für Angeborene Immunität), which has a research focus on the immune mechanisms that cause inflammatory reactions. The innate immune system forms part of the body's own defence mechanism and is able to respond rapidly and directly to a number of alarm signals that appear in the tissue environment. These triggers not only include viruses, bacteria and fungi but also certain crystals and other substances that occur during infections of in stress situations. The strength of the innate immune system is that it can respond very quickly to situations that are of danger to the host. The problem, however, is that it can also overshoot the mark. This type of overreaction is also seen in the case of pneumoconioses such as the black lung, a disease which frequently affects miners. In these lung diseases, a chronic inflammatory reaction is triggered by inhaled crystals made of silicates or asbestos. The molecular mechanisms of crystal recognition are similar to those triggered by cholesterol crystals in blood vessels.
Starting point for developing new drugs
There is still a piece of the jigsaw puzzle missing which researchers need to complete the overall picture. “We don't know precisely how the cholesterol crystals activate the inflammasome”, says Professor Latz. The findings of this study however, offer some starting points for developing new drug therapies. At present, statins are widely used in therapy. Statins reduce the synthesis of endogenous – i.e. the body's self-produced cholesterol and diminish the risk of heart attack or stroke, but they cannot inhibit the absorption of cholesterol from ones diet.
Estimates by the World Health Organization put the number of people now dying from cardiovascular diseases at almost 17 million per year. This means that one in four deaths worldwide is caused by atherosclerosis.
The number of women suffering from gout has doubled in the last 20 years, research shows.
The problem is traditionally associated with middle aged men but evidence suggests the disease is also a concern for women. According to a survey, the prevalence of gout in women was 3.5 per cent for ages 60 to 69, 4.6 per cent in the 70 to 79 age group, and 5.6 per cent in those aged 80 or older.
Gout is a common and painful inflammatory arthritis caused by elevated uric acid levels in the blood. When too much uric acid builds up in joint fluid, crystals form and cause joint swelling and inflammation. Dr Hyon Choi, from the Boston University School of Medicine, which conducted the review of previous research, said: “We identified 104 gout cases in women and 200 in men. “Our study found that higher levels of uric acid in the blood increase the risk gout risk for women.”
This study, the first to examine the relationship between uric acid levels and gout risk in women, also evaluated purported risk factors for gout and found that increasing age, obesity, hypertension, alcohol use, and diuretic use to be among the leading contributors for women.
The research team analysed data from 2,476 women and 1,951 men, and evaluated uric acid levels and risk factors for gout that included: age, body mass index (BMI), alcohol consumption, hypertension, medication use – including diuretics and hormone replacement therapy – blood glucose and cholesterol levels, and menopause status. The study looked at men and women from various health sources and records over an average of 28 years. The researchers found age, obesity, alcohol consumption, diuretic use, and hypertension were all independently associated with higher risk of gout incidence in women.
The study was published in the April issue of Arthritis & Rheumatism, a journal of the American College of Rheumatology.