RESUMO
OBJECTIVES: To study the level of serum vitamin K2 (VitK2) and its association with bone metabolism markers osteocalcin (OC), type I procollagen amino-terminal peptide (PINP), and type I collagen carboxy-terminal peptide (CTX) in children. METHODS: A prospective analysis was performed on 1 732 children who underwent routine physical examination from October 2020 to October 2021. The serum levels of VitK2 and 25-hydroxy vitamin D [25(OH)D] were measured. According to age, they were divided into four groups: <1 year, 1-3 years group, >3-6 years group, and >6-14 years. A total of 309 children with 25(OH)D≥50 nmol/L were screened out, and serum levels of OC, PINP, and CTX were measured to investigate the correlation of the serum levels of OC, PINP, and CTX with serum VitK2 levels in different age groups. RESULTS: The prevalence rate of serum VitK2 deficiency was 52.31% (906/1 732). The VitK2 deficiency group had higher prevalence rates of overweight/obesity and growth pain (≥3 years of age) than the normal VitK2 group (P<0.05). There were differences in the prevalence rate of serum VitK2 deficiency (P<0.0083) and the serum level of VitK2 (P<0.05) between the 1-3 years group and the >6-14 years group. The <1 year group had a higher serum level of CTX and a lower serum level of PINP than the >3-6 years group and the >6-14 years group (P<0.05). The <1 year group had a lower serum level of OC than the >6-14 years group (P<0.05). Serum VitK2 level was positively correlated with OC level (rs=0.347, P<0.01), and CTX level was negatively correlated with PINP level (rs=-0.317, P<0.01). CONCLUSIONS: Serum VitK2 deficiency may be associated with overweight/obesity. Serum VitK2 may affect the level of OC and even bone health.