Ethnic differences in height growth trajectories and early life factors: findings from the UK Millennium Cohort Study

Height growth is an important biomarker for early life exposures that influence later disease risk. Previous studies show that ethnic minority children in the UK tend to be born lighter but experience more rapid infancy growth than White peers. However, whether subsequent child-to-adolescent growth differs by ethnic group is insufficiently understood. We used the data from 15,239 singletons in the UK Millennium Cohort Study and applied mixed-effects cubic growth models to examine ethnic differences in height trajectories between 3y and 14y. Models were subsequently adjusted for potential early life explanatory factors. Compared with White counterparts, South Asian children had lower birthweight and shorter parents on average, but were slightly taller at 3y by 0.5cm [95% CI: 0.2–0.9] and had comparable childhood and adolescent trajectories, except that girls had a slower growth in adolescence. Height of South Asians relative to White children increased after adjusting for birthweight (taller by 1.3cm at 3y). Black African/Caribbeans were taller than White children at all ages between 3y and 14y (at 3y boys: 2.2cm, 1.2–2.7; girls: 3.2cm, 2.6–3.8) with height differences widening in childhood and reducing in adolescence. Adjustment for potential explanatory factors did not alter these differences. Despite having lower birthweight, contemporary UK South Asian children had comparable child-to-adolescent growth as White children. Black African/Caribbeans were considerably taller than other ethnic groups. Future research is needed in understanding the role of genetic and other environmental factors (such as diet) in these distinct growth patterns across ethnic groups and their health implications.