Abstract
BACKGROUND AND AIMS: Understanding bone mass accumulation patterns and factors influencing them during growth is important for preventing osteoporosis later in life. This study investigated longitudinal changes in bone mineral content (BMC), bone mineral density (BMD), and bone mineral apparent density (BMAD) during growth, with the aim of estimating the age at which peak bone mass (PBM) is achieved in males and females. It also examined the effects of puberty, age, body mass index (BMI), sex, socioeconomic status (SES), and habitual exercise on these bone parameters during adolescence and early adulthood. METHODS: This retrospective cohort study included 159 participants. Bone densitometry was performed using dual-energy x-ray absorptiometry (DXA) during two assessments. Anthropometric measurements were obtained, and demographic data, pubertal stage, medical history, SES, and exercise habits were collected through a structured questionnaire administered by a physician. RESULTS: Rates of change in total body BMC (TBBMC) and BMD (TBBMD) decreased with advancing age and pubertal stage, with the highest rates observed at ages 9-11 and Tanner stage 1. Across all ages up to 18 years, males showed significantly higher rates than females. Peak TBBMC and TBBMD occurred at 25.7 and 26.2 years in males, and 24.8 and 24.0 years in females. After adjusting for bone size, BMAD peaks at the femoral neck and lumbar spine were 21.2 and 23.8 years in males, and 24.8 and 24.1 years in females. Linear mixed model analysis indicated that older age, higher BMI, male sex, higher SES (significant for BMD), and greater physical activity positively influenced TBBMC and TBBMD until peak values were reached. CONCLUSION: Bone accumulation was greater in adolescence than in early adulthood. PBM was generally reached in the mid-third decade, with females attaining it earlier. Age, sex, BMI, SES, and exercise positively influenced TBBMC and TBBMD during adolescence and early adulthood.