The results of the model comparison in the NFBC1966 for infant height were consistent with the model comparison on early weight growth in another study [17] in Congolese infants, where the Reed1 model showed the best fit. As far as we know, there are no published model comparisons for early height growth in other studies. For the whole period of growth from birth into adulthood, the superiority of the JPPS model over slightly simpler parametric models such as the Preece and Baines (PB1) and modified Shohoji and Sasaki (SSC) models has been described elsewhere [18], and was not tested in our data set. As expected, JPA-2 fitted better than JPPS into our data. The high correlation between ATO and age at PHV2 (Table S1) estimated from the JPA-2 model largely explains the similarities in the results between the two phenotypes. There was also a moderately high inverse correlation between PHV in puberty with the timing of pubertal height growth spurt. This may contribute to some overlap in the genetic association results, and has to be acknowledged in the interpretation of the results.
