Higher levels of skin advanced glycation end-products (AGEs) are associated with increased sarcopenia prevalence in middle-aged and elderly persons, investigators reported in the Journal of Clinical Endocrinology and Metabolism. The researchers sought to determine whether skin autofluorescence (SAF) was associated with sarcopenia in a Dutch cohort of middle-aged and elderly persons.
Sarcopenia was categorized according to the European Working Group on Sarcopenia revised criteria. Probable sarcopenia was defined as having only weak hand grip strength (HGS), confirmed sarcopenia was defined as having weak HGS and low appendicular skeletal mass index (ASMI) simultaneously, and severe sarcopenia was defined as having weak HGS, low ASMI, and slow gait speed simultaneously.
Skin autofluorescence was measured with the AGE Reader (DiagnOptics Technologies BV, Groningen, the Netherlands). A small area of forearm skin was illuminated with an excitation light source from the AGE Reader with a peak wavelength of 370nm. The study authors also assessed muscle mass, strength, and performance. Multivariate linear and logistic regression were used to adjust for age, sex, body fat percentage, height, renal function, diabetes, and smoking status.
A total of 2744 participants (median age, 74 years [interquartile range, 66.9-81.1]; 43.8% male) of Northern European background were included from the Rotterdam Study. The mean (±SD) value of SAF among participants was 2.38±0.48 arbitrary units, and the mean body mass index was 27.5±4.2 kg/m2.
The cohort had a prevalence of 7% (CI, 6.2-7.9) for low ASMI, 24% (CI, 23-26) for weak HGS, and 3.5% (2.9-4.3) for confirmed sarcopenia. In a subgroup of 2080 participants with data on gait speed, no major differences were found in the demographic, clinical, and skeletal muscle parameters compared with those from the full cohort. The prevalence of low gait speed was 2.9% (2.3%-3.9%) and 0.6% (0.3-1.1%) for those with severe sarcopenia.
Skin autofluorescence values were significantly higher in male participants vs female participants (2.50±0.49 vs 2.30±0.46, P < .0001). Skin autofluorescence had an inverse association with ASMI after adjustment for potential confounders (β = –0.062 [–0.092, –0.032], P = 3 × 10-5) and a negative association with gait speed (β = –0.074 [–0.116, –0.033], P = 3 × 10-4).
Continuous SAF was significantly associated with weak HGS (odds ratio [OR], 1.36; 95% CI, 1.09-1.68). In addition, increased SAF as a continuous variable was associated with confirmed sarcopenia (OR, 2.01; 95% CI, 1.33-3.06).
Elevated SAF levels were significantly and negatively associated with hand grip strength, gait speed, and ASMI independently of the potential confounders, noted the researchers.
Study limitations include the cross-sectional design and inclusion of only Caucasian individuals. Also, the investigators could neither exclude residual confounding nor the potential impact of survival bias in this aging cohort.
“On a large scale such as in primary care, implementation of noninvasive SAF measurements can be an efficient solution to screen the elderly for the risk of sarcopenia once a causal association and a good predictive capability have been established,” the study authors stated.
Waqas K, Chen J, Trajanoska K, et al. Skin autofluorescence, a non-invasive biomarker for advanced glycation end-products, is associated with sarcopenia. J Clin Endocrinol Metab. Published online August 28, 2021. doi:10.1210/clinem/dgab632