Parental height modifies the association between linear growth and neurodevelopment in infancy.

AIM: To estimate the extent to which maternal and paternal height modify the association between length-for-age Z-score (LAZ) and neurodevelopmental outcomes assessed by the Bayley Scales of Infant and Toddler Development, 3rd Edition (Bayley-III).

METHODS

Baseline data from a clinical trial in 600 Nepalese infants aged six to 11 months with LAZ less than -1 were utilised. The primary exposure was the LAZ score, interaction variables were maternal and paternal height, and the outcomes were Bayley-III cognitive, language and motor scaled scores. Linear regression and generalised additive model (GAM) were used to identify potential interactions.

RESULTS

Linear regression analysis stratified by parental height categories showed that association between unit increase in LAZ and cognitive scaled score differed across maternal (normal height: ß 1.16, 95% CI; 0.75, 1.57 and short height: ß 0.67, 95% CI; 0.28, 1.05) and paternal (normal height: ß 1.32, 95% CI; 0.91, 1.72 and short height: ß 0.61, 95% CI; 0.03, 1.18) height categories. Maternal height also modified the association between LAZ and fine motor scaled score.

CONCLUSION

The association between LAZ and neurodevelopmental outcomes was attenuated when maternal and paternal height was taken into account. Parental stature should be considered when using LAZ as a proxy for neurodevelopment among infants.