Flexible nonlinear estimates of the association between height and mental ability in early life

To estimate associations between early-life mental ability and height/height-growth in contemporary US children.

Structured additive regression models are used to flexibly estimate the associations between height and mental ability at approximately 24 months of age. The sample is taken from the Early Childhood Longitudinal Study-Birth Cohort, a national study whose target population was children born in the US during 2001.

A nonlinear association is indicated between height and mental ability at approximately 24 months of age. There is an increasing association between height and mental ability below the mean value of height, but a flat association thereafter. Annualized growth shows the same nonlinear association to ability when controlling for baseline length at 9 months.

Restricted growth at lower values of the height distribution is associated with lower measured mental ability in contemporary US children during the first years of life.