Fat mass is inversely associated with serum carboxymethyl-lysine, an advanced glycation end product, in adults

High levels of circulating advanced glycation end products (AGE) are associated with cardiovascular disease, diabetes, chronic kidney disease, and increased mortality, but factors that influence levels of circulating AGE are not well known. Our objective was to characterize the relationship between serum carboxymethyl-lysine (CML), a major circulating AGE, and body composition in adults. In a cross-sectional study, total body DXA was performed and serum CML was measured in 592 adults, aged 26-93 y, from the Baltimore Longitudinal Study of Aging. Median (25th, 75th percentile) CML concentrations were 2.26 (1.86, 2.67) μmol/L. Total fat mass [β = -0.17 (95% CI -0.10, -0.24); P < 0.0001], truncal fat mass [β = -0.17 (95% CI -0.10, -0.25); P < 0.0001], and appendicular fat mass [β = -0.13 (95% CI -0.05, -0.20); P = 0.001] per 1 SD increase were inversely associated with serum CML in separate multivariate linear regression models, adjusting for age, sex, BMI, systolic blood pressure, TG, HDL cholesterol, and renal function. Lean body mass was not independently associated with serum CML. These findings suggest that serum CML concentration is strongly affected by body fat, possibly because CML is preferentially deposited in fat tissue or because adipocytes affect the metabolism of AGE.