Zinc status and bone mineralisation in adolescent girls

Abstract

The aim of the project was to assess the relationship between zinc status and bone mineralisation in pre-menarcheal adolescent girls. One hundred and thirty-nine healthy pre-menarcheal girls (Tanner pubic hair stage ⩽4), aged 12.4±1.0 years, had two visits at an interval of 2 years. Serum and urine zinc concentrations (Zn S; Zn U; Zn U/ creatinine), insulin-like growth factor 1 (IGF-I), and markers of bone turn-over, i.e. osteocalcin and parathormone (PTH), concentrations were measured at the first visit. Lumbar (L2–L4) bone mineral content and density (BMC, BMD) were measured at both visits. BMC and BMD and their increase at the follow-up after 2 years were compared with biochemical data by multiple regression. The stage of puberty was added as a covariable in the analysis. At the first visit, a significant correlation was found between sexual maturity and initial BMC, BMD, height, weight, and IGF-I. Zn S was negatively correlated with osteocalcin. Zn U showed a positive correlation with BMC, BMD, IGF-I, height, weight, and PTH. At the second visit, sexual maturity showed a positive correlation with BMD and weight increments and a negative one with BMC and height gains. Zn S was significantly related with BMD increase. These correlations suggest that zinc plays a role in normal growth and bone mineralisation during puberty onset.