Association Between Fat, Bone Mass, and Tophaceous Gout

Tophaceous gout is a more severe form of gout that develops in people with chronic uncontrolled gout.  It is a result of the deposition of uric acid crystals that develop in areas such as fingers, hands, feet, elbows, and knees. People with tophaceous gout typically experience symptoms of severe pain, swelling of the joints, and discoloration of the skin.

Gout is quite prevalent, affecting two out of every 100 adults in the US. There has been literature establishing that uric acid (UA) is associated with bone mineral density (BMD); however, the associations between UA, bone spurs (osteophytes), fat, and muscle have yet to be explored in depth.

Researchers at Chang Gung University College of Medicine [location?] investigated this association and the possible factors that can predict the risk of developing tophaceous gout. The cross-sectional case-control study, published in the Journal of Investigative Medicine, included 65 patients with tophaceous gout, and a control group comprised 85 patients without gout. Patients underwent BMD and body composition examinations. Age, sex, alcohol consumption, smoking status, and radiographs of both knees were also recorded.

The mean body mass index (BMI) of the tophaceous gout group was 28.38 kg/m² compared with 24.42 kg/m² in the group without gout. Moreover, overall fat mass and appendicular lean mass were found to be higher in the tophaceous gout group. There were no significant differences between groups regarding lumbar spine and femoral neck BMD; however, the total hip BMD was higher in those with tophaceous gout. More osteophyte formation in the knee joint was observed in those with tophaceous gout.

After performing a logistic regression analysis, high fat mass, high muscle mass, and knee osteophyte formation were associated with tophaceous gout. Higher femoral neck and total hip BMD, on the other hand, were not associated with tophaceous gout.

“This study has shown for the first time that the association between tophaceous gout and risk factors is largely determined by fat mass (a specific measure of fat deposition) rather than BMI,” the authors wrote. “Our findings may have clinical implications in primary prevention strategies for chronic diseases, which may require monitoring of high visceral adipose tissue fat mass and consequent high-plasma UA levels as potential prognostic factors.”