Circulating lumican as a potential biomarker for osteosarcopenia in older adults.

In vitro and animal experiments demonstrated that lumican exerts anabolic effects on bone and muscle by stimulating osteoblastogenesis, suppressing osteoclastogenesis and increasing myogenesis. However, the relationship between circulating lumican and musculoskeletal phenotypes in humans remains unclear. We aimed to analyze the relationship between serum lumican levels and osteosarcopenia in older adults. Blood samples were collected from 134 participants (age: 65 years and older) who underwent comprehensive assessment of bone and muscle phenotypes. Osteoporosis and sarcopenia were diagnosed based on World Health Organization and Asian consensus guidelines, respectively. Osteosarcopenia was defined as the simultaneous presence of osteoporosis and sarcopenia. After adjusting for sex, age, and body mass index, older adults with osteosarcopenia had 20.2 % lower serum lumican levels than those without (P = 0.010). The odds ratio (OR) for osteosarcopenia per standard deviation decrease in serum lumican level was 4.17 (P = 0.003). Consistently, higher serum lumican levels were correlated with higher bone mass at all measured sites (P = 0.004 to 0.045) and higher grip strength (P = 0.023). Furthermore, participants in the lowest tertile (T1) had 7.56-fold higher OR for osteosarcopenia (P = 0.024) than those in the highest lumican tertile (T3). In conclusion, these findings clinically validate previous experimental data showing the musculoskeletal protective effects of lumican and suggest that blood lumican levels could be used as a potential biomarker to assess the risk of not only osteosarcopenia but also osteoporosis or sarcopenia in older adults.