Changes in head dimensions in children from Northern Kashubia (Pomerania, Poland) during 60 years.

Abstract

Over 100 years ago Franz Boas introduced the term 'cranial plasticity' defined as a response to various environmental factors. The subject is under continuous debate. Some researchers have concluded that cephalic growth is responsible to environmental change meanwhile other have found that cephalic proportion are highly heritable and do not respond readily to environmental insults. While secular trend in growth is commonly observed, head dimensions vary significantly not only between different regions of the world but also in those regions themselves. Adam Wrzosek and Michał Ćwirko-Godycki initiated studies of Kashubian children as early as in 1925 and continued them into 1936. Throughout those 11 years they accumulated measurement data regarding body height and craniometric features. The research included boys and girls from 18 localities. Sixty years later, anthropometric measurements were conducted on primary school children from nine of the original localities. The aim of our study was to determine the direction of changes in head dimensions and corresponding indices in rural children from the Kashubia region examined 60 years after Ćwirko-Godycki and Wrzosek's study emphasizing great socio-economic status improvement. All children that were examined by us in 1997 are significantly taller (by between 5.18cm and 14.74cm) than their peers 60 years ago, their heads are longer (by between 2.69mm and 10.41mm), they have broader foreheads (by 3.79 - 7.24mm), wider faces (by 4.68 - 8.09mm) and mandibles (by 5.04 - 7.40mm), larger head circumferences (by 0.64 - 2.22cm) and larger total face heights (by 2.15 - 8.13mm). The effect persists in all age groups (from 7 to 14 years old). All the noted differences are statistically significant by p < 0.05. The smallest differences were observed in head breadth (between 0.62 and 3.5mm), with statistical significance only reached in 9-year-old girls, and 11- and 14-year-old boys. Since migration in Kashubian villages was minimal in the period in question and the mating radius for couples living there was small, it can be assumed that the chance of introducing 'new' genes into the population was low. We thus gravitate towards environmental factors being the major contributors to the observed changes, doubtlessly to do with an improvement in socio-economic status.