Skin advanced glycation end-product accumulation is negatively associated with calcaneal osteo-sono assessment index among non-diabetic adult Japanese men

SUMMARY: This study aims to determine the relationship between advanced glycation end-product (AGE) accumulation in skin tissue and bone strength, assessed by quantitative ultrasound, among healthy adult Japanese men. The results of the study suggest that men with higher AGE accumulation in skin tissue have a lower osteo-sono assessment index. INTRODUCTION: AGE accumulate in bone collagen with age and diabetes and decrease the mechanical properties of bone. Although increased AGE levels are associated with fractures among diabetic patients and elderly women, it is unclear whether a relationship between increased AGE levels and bone strength is present in apparently healthy adult males. The aim of this study was to determine the relationship between AGE accumulation in tissue and the mechanical properties of bone among adult Japanese men, using quantitative ultrasound as a surrogate measure of the latter. METHODS: Skin autofluorescence (AF), which is a noninvasive method for measuring tissue AGEs, and osteo-sono assessment index (OSI), which is determined by quantitative ultrasound, were measured in 193 adult Japanese men (median age 43 years; interquartile range 37.0–55.0 years). RESULTS: Adjusted for age, BMI, calcium intake, physical activity, smoking status, and education level, log-transformed skin AF had a negative association with log-transformed OSI (β = −0.218, P < 0.01). Adjusted geometric means (95% CI) for OSI across the tertiles of skin AF were 2.81 (2.75–2.87) for the lowest tertile, 2.81 (2.74–2.87) for the middle tertile, and 2.66 (2.61–2.73) for the highest tertile; thus, OSI for the highest skin AF appeared to be 5.0% lower than that for the lowest and middle skin AF tertiles (P < 0.01). CONCLUSION: Among apparently healthy adult Japanese men, those with higher skin AF had a lower OSI, indicating a relationship between AGE accumulation and bone strength. A long-term prospective study is required to clarify the causality.