Bone growth during childhood and adolescence are strongly linked to the risk of bone fracture and to bone health at older ages. McCormack and colleagues carried out a longitudinal study clarifying patterns of bone growth in children and showed that the risk of bone fracture is highest just before the greatest period of bone mass increase around 12-14 years of age.
Long-term bone health depends on bone mass and bone density achieved in childhood and early adulthood.However, growth in height does not occur at the same rate as growth in mass, which may contribute to an increased risk of bone fracture in children.
To clarify how growth, bone mass, and bone health are related, McCormack and colleagues published the results of a longitudinal study investigating bone mass and density in children in JAMA Pediatrics.
The researchers included data from 2014 healthy children from throughout the United States who entered the study between 5 and 19 years of age. These children were then evaluated each year for up to 7 years. The participants were equally divided by sex, and 23.8% of the participants were African-American. Researchers assessed height, weight, pubertal status, and percentile for body mass and height. In addition, the researchers used special x-ray scans to measure bone density at different locations in the body. The participants were also asked about any fractures they experienced each year.
African American boys and girls grow significantly faster on average than non-African American children. Boys acquire the most bone mineral content at 14 years of age, whereas girls acquire it around 12 years of age, and up to 11% of bone mineral density is acquired in late adolescence after growth has finished. Before this period, growth in height is faster than increases in bone density, and fracture risk is highest overall. Both height and bone mineral density increases are tied to puberty, and earlier puberty is associated with faster growth. Finally, bone loss of can occur beginning in early adulthood—as soon as bone growth is finished.
The implications of this study are profound. The newfound knowledge that a significant amount of bone density is achieved after adult height is reached indicates that there remains an important nutritional opportunity late in adolescence to optimize bone mass.
This research clarifies patterns of bone growth and how they are linked to bone health in children and young adults. Future research following participants into older ages will be required to clarify the relationship of these early stages to the risk of osteoporosis and other bone diseases later in life.
Written by C.I. Villamil
Reference: McCormack et al. 2017. Association between linear growth and bone accrual in a diverse cohort of children and adolescents. JAMA Pediatrics.