Height and weight velocity in the first 6 years of life are associated with bone mass at age 7 years, with the second and third years of life being particularly sensitive periods of growth for skeletal development, according to study results published in Bone.
Previous studies have found that growth in early childhood has a strong association with bone properties, with decreasing magnitude thereafter. The goal of this study was to assess the association between height and weight velocities across different age periods with bone measures at age 7 years.
The study was based on a subsample of 1853 of children (48% girls) from the Generation XXI birth cohort with available growth and bone density data. Average weight and length/height growth trajectories were estimated with linear spline multilevel models based on data collected during health examinations. The age intervals for weight growth included early neonatal (0-10 days), early infancy (10 days-3 months), late infancy (3-12 months), early childhood (1-3 years), and late childhood (3-6 years). Age intervals for length/height growth included early infancy (0-3 months), late infancy (3-12 months), early childhood (1-3 years), and late childhood (3-6 years).
Height and weight velocity in the first 6 years of life were associated with bone mass at age 7 years. Growth between age 1 to 3 years presented the strongest association with bone mineral density measures: for both girls and boys, 1 SD increase in early childhood weight velocity was linked to average increases in height-adjusted bone mineral content z score of 0.27 (95% CI, 0.22-0.32) and 0.24 (95% CI, 0.19-0.29), respectively.
Height velocity was associated in a similar fashion; 1 SD increase in height velocity during the second and third years of life was associated with average increases of 0.12 (95% CI, 0.07-0.17) in girls and 0.11 (95% CI, 0.06-0.16) in boys for height-adjusted bone mineral content z score. Adjustment for preceding growth attenuated all associations from early infancy to early childhood.
The study had several limitations, including a cohort limited to children born in Portugal, missing data on growth and bone variables, use of different equipment to measure growth, and possible residual confounding.
“Our study suggests that the toddler years might be a particularly sensitive period for the effect of growth on bone development. If a causal interpretation is to be extracted, our results point to the importance of identifying disturbances to normal growth in early childhood that may impact bone health before peak bone mass,” concluded the researchers.
Monjardino T, Amaro J, Fonseca MJ, Rodrigues T, Santos AC, Lucas R. Early childhood as a sensitive period for the effect of growth on childhood bone mass: Evidence from Generation XXI birth cohort. Bone. 2019;127:287-295.