Intentionally losing weight and then regaining it may increase men's risk for gallstones later in life, according to a report in the November 27 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Gallstone disease--which occurs when a solid mass of cholesterol, bile and calcium salts forms in the gall bladder--is common among adults in Western countries, according to background information in the article. Obesity is a risk factor for gallstone disease, as is rapid weight loss for the treatment of severe obesity. "Although approximately 30 percent of adult U.S. men are trying to lose weight, intentional weight loss is rarely sustained and is often associated with unintentional weight regain, leading to weight cycling," the authors write. "The long-term health consequences of repeated intentional weight loss and the mechanisms of weight recovery are still not well understood. Studies have suggested that large weight fluctuations at some point earlier in life represent an independent risk factor for chronic diseases, including metabolic syndrome."
To assess whether weight cycling influenced the risk of developing gallstones, Chung-Jyi Tsai, M.D., Sc.D., University of Kentucky Medical Center, Lexington, and colleagues analyzed data from 24,729 men who were part of the Health Professionals Follow-up Study. The men provided information about any weight fluctuations between 1988 and 1992. They were then sent a questionnaire every two years from 1992 to 2002 to monitor whether they had developed gallstone disease.
A total of 7,443 men reported that they were weight maintainers--in other words, that they had remained within five pounds of their initial weight between 1988 and 1992. Of those who were weight cyclers, 10,027 were light cyclers (who had a maximum weight loss per attempt of between 5 and 9 pounds); 5,185 were moderate cyclers (weight loss between 10 and 19 pounds); and 2,074 were severe cyclers (weight loss of 20 pounds or more).
Overall, 1,222 cases of symptomatic gallstones developed between 1992 and 2002. Gallstones were more likely in each of the weight cycling groups than in the weight maintaining group. Those who were light cyclers had a 21 percent increased risk, moderate cyclers had a 38 percent increased risk and severe cyclers increased their risk by 76 percent, compared with weight maintainers. Risk for gallstones also increased when the number of weight cycles increased, with severe cyclers who had more than one weight cycle experiencing nearly double the risk of weight maintainers. The associations remained when researchers considered each participant's body mass index (BMI), further suggesting that it is the weight cycling, rather than being overweight or obese alone, that increases risk.
"The potential mechanisms contributing to the association between weight cycling and gallstone formation observed in our study are likely to be multiple," the authors write. When an individual loses and then regains weight, much of that additional weight is made up of body fat. "Studies have shown that large swings of body weight, especially the phase of weight recovery, are particularly sensitive to the accumulation of body fat and to the development of metabolic abnormalities, including insulin resistance, and thereby may facilitate gallstone formation," they write. In addition, levels of the compounds leptin and insulin in the blood have been shown to be higher in weight cyclers than weight maintainers, which could also contribute to gallstone risk.
(Arch Intern Med. 2006;166:2369-2374. Available pre-embargo to the media at www.jamamedia.org.)
Editor's Note: This study was supported by research grants from the National Institutes of Health and from the Centers for Disease Control and Prevention. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
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