Some scholars have found that chordin-like protein can enhance the role of BMP in inducing osteoblast differentiation (45, 46). A total of 10 plasma protein markers could reduce the risk of osteoporosis, among which ANKED46, killer cell lectin-like receptor subfamily F member 1 (KLRF1), LPO, and CA9 may have a strong causal relationship with osteoporosis. Here, CA9 is linked to osteoporosis.