Body Fatness Increases Risk of Monoclonal Gammopathy of Undetermined Significance in the U.S. Population

ObjectiveCurrent evidence on whether obesity is associated with MGUS remains inconsistent. This study aims to evaluate the association between objectively measured obesity markers and the risk of developing MGUS, using nationally representative data from the U.S. population. MethodData came from the third National Health and Nutrition Examination Survey III (1988-1994) and continuous NHANES (1999-2004). Multivariable-adjusted odds ratios (aOR) and 95% confidence intervals (CIs) for the association between the risk of developing MGUS and seven obesity markers--including baseline body mass index (BMI), maximum lifetime BMI, waist circumference (WC), waist-hip ratio (WHR), total body fat, fat-free mass, and body percentage fat--were estimated using logistic regression. ResultsIn the study cohort, a total of 364 participants tested positive for MGUS, compared to 12,043 participants without MGUS. Multivariate logistic regression analysis indicates that each 1% increase in body fat percentage is associated with a 4% (aOR: 1.04, 95% CI [1.01, 1.07]) higher risk of MGUS. Each 1% increase in body fat percentage is also associated with a 6% (aOR: 1.06, 95% CI [1.02, 1.10]) higher risk of non-IgM MGUS. No statistically significant association was found between MGUS and other obesity markers, including baseline BMI, maximum lifetime BMI, WC, WHR, and fat-free mass. ConclusionOur findings show that obesity is associated with an increase in the risk of MGUS. However, many obesity markers, including the commonly used BMI, fail to capture this association.