Association Between Age at Puberty and Bone Accrual From 10 to 25 Years of Age
Authors: Ahmed Elhakeem, Monika Frysz, Kate Tilling, Jon H. Tobias, Deborah A. Lawlor
Journal: JAMA Network Open (2019)

<h3>Importance</h3> Bone health in early life is thought to influence the risk of osteoporosis in later life. <h3>Objective</h3> To examine whether puberty timing is associated with bone mineral density accrual up to adulthood. <h3>Design, Setting, and Participants</h3> This cohort study used data from the Avon Longitudinal Study of Parents and Children, a prospective population-based birth cohort initiated in 1991 to 1992 in southwest England. The participants were 6389 healthy British people who underwent regular follow-up, including up to 6 repeated bone density scans from ages 10 to 25 years. Data analysis was performed from June 2018 to June 2019. <h3>Exposures</h3> Age at puberty from estimated age at peak height velocity (years). <h3>Main Outcomes and Measures</h3> Gains per year in whole-body bone mineral density (grams per square centimeter), assessed by dual-energy x-ray absorptiometry at ages 10, 12, 14, 16, 18, and 25 years and modeled using linear splines. <h3>Results</h3> A total of 6389 participants (3196 [50.0%] female) were included. The mean (SD) age at peak height velocity was 13.5 (0.9) years for male participants and 11.6 (0.8) years for female participants. Male participants gained bone mineral density at faster rates than did female participants, with the greatest gains in both male participants (0.139 g/cm<sup>2</sup>/y; 95% CI, 0.127-0.151 g/cm<sup>2</sup>/y) and female participants (0.106 g/cm<sup>2</sup>/y; 95% CI, 0.098-0.114 g/cm<sup>2</sup>/y) observed between the year before and 2 years after peak height velocity. When aligned by chronological age, per 1-year older age at puberty was associated with faster subsequent gains in bone mineral density; the magnitudes of faster gains were greatest between ages 14 and 16 years in both male participants (0.013 g/cm<sup>2</sup>/y; 95% CI, 0.011-0.015 g/cm<sup>2</sup>/y) and female participants (0.014 g/cm<sup>2</sup>/y; 95% CI, 0.014-0.015 g/cm<sup>2</sup>/y), were greater in male participants (0.011 g/cm<sup>2</sup>/y; 95% CI, 0.010-0.013 g/cm<sup>2</sup>/y) than in female participants (0.003 g/cm<sup>2</sup>/y; 95% CI, 0.003-0.004 g/cm<sup>2</sup>/y) between ages 16 and 18 years, and were least in both male participants (0.002 g/cm<sup>2</sup>/y; 95% CI, 0.001-0.003 g/cm<sup>2</sup>/y) and female participants (0.000 g/cm<sup>2</sup>/y; 95% CI, −0.001 to 0.000 g/cm<sup>2</sup>/y) between ages 18 and 25 years. Despite faster gains, older age at puberty was associated with persistently lower bone mineral density, changing from 0.050 g/cm<sup>2</sup>(95% CI, −0.056 to −0.045 g/cm<sup>2</sup>) lower at age 14 years to 0.047 g/cm<sup>2</sup>(95% CI, −0.051 to −0.043 g/cm<sup>2</sup>) lower at age 25 years in male participants and from 0.044 g/cm<sup>2</sup>(95% CI, −0.046 to −0.041 g/cm<sup>2</sup>) to 0.034 g/cm<sup>2</sup>(95% CI, −0.036 to −0.032 g/cm<sup>2</sup>) lower at the same ages in female participants. <h3>Conclusions and Relevance</h3> People with older pubertal age should be advised on how to maximize bone mineral density and minimize its decrease in later life to help prevent fracture and osteoporosis.