Changes in schoolgirls' body measurements during a 30 year period

Two data-sets containing the anthropometric measurements of Estonian schoolgirls aged 7-18 were analysed, one (set A) from the late sixties, size 1627 and the other (set K) from the late nineties, size 1546. In all data sets 8 measurements--three height, three breadth measures, chest circumference and mass--were measured using the same methodology, as well as BMI was calculated. The means of all the characteristics in age groups (size 100-150 individuals) were calculated and growth curves of means were approximated using polynomial least squares approximation. The maximal velocity points were found and the growth intensities in different body build groups were compared. It was proved that the usage of cross-sectional data for estimating growth curves is suitable for estimating the velocity of acceleration in different age groups. We found that the height of Estonian girls has increased during the last 30 years by about 4-5%, the breadth measurements--by about 1-2%, chest circumference up to 8% and BMI has decreased by 3-5%. The changes are quite modest in pre-puberty, most significant for girls aged 12-16 and smaller again for girls aged 17 and more. The maximal growth velocity has shifted for all characteristics to the earlier time. Comparison of different body build groups showed that the small girls of the sixties are quite similar to small girls in the nineties, but the differences are greater in the case of large and pycnomorphic girls.