Reference values for bone mass in young athletes: a cross-sectional study in São Paulo, Brazil

Reference values for bone mass in young athletes need to be used for screening purposes, and country/regional reference values should be used to improve precision of comparisons. The aim of the present study was to develop reference values for bone health variables in Brazilian young athletes. The bone mass content (BMC), bone mass density (BMD), and total body less head (TBLH) BMD using dual-energy X-ray absorptiometry were measured in 702 young athletes (327 men and 375 women) aged 8.5-18.5 years, divided into 5 groups, according to their age: group 1 (8.5-10.5 years), group 2 (10.6-12.5 years), group 3 (12.6-14.5 years), group 4 (14.6-16.5 years), and group 5 (16.6-18.5 years). Comparisons between the sexes and ages were performed and age-sex-smoothed reference values were constructed. Male athletes presented high BMC and BMD than female athletes in age groups 3, 4, and 5 (p < 0.005) and high TBLH BMD than female athletes in age groups 4 and 5 (p < 0.005). Reference values, including the percentiles are presented for the bone health variables of each sex and age group. The age-, sex-, and ethnic-specific reference data for bone variables presented in this study enabled more precise reference data for young Brazilian athletes. These data may assist in monitoring changes during an athletes' growth and different phases of athletic training.