Secular trend: morphologic variability of children population of lisbon between 1991 and 2001

Introduction

The long term growth modifications are especially expressed in height, body mass, body composition, proportionality and maturation alterations. They occur with different intensity in most developed countries. In this sense we intended to study the results of secular trend in the Lisbon children morphology, between 1991 and 2001.

Methods

The study included 5440 Portuguese boys and girls, aged 4 to 11 years, who were divided into two groups: 2273 children evaluated in 1991 (1106 boys and 1167 girls) and 3167 children evaluated in 2001 (1580 boys and 1587 girls) The anthropometric measures were obtained according to Fragoso and Vieira (2000), the somatotype was evaluated in agreement with Heath and Carter (1967), and body composition was calculated through anthropometric equations selected in harmonization with the age and children’s sex. The percentiles and anthropometric standard were calculated by LMS statistical algorithm (Hoaglin et al., 1993). Besides the descriptive statistic, the t test was used to assess the differences between 1991 and 2001 populations.

Results

The comparison between 1991 and 2001 children showed that, for the majority of ages between 4 and 11 years, boys and girls measured in 2001 were higher (+ 2.5 cm), heavier (+ 1.3 kg), had bigger trunks (+ 1.6 cm), bigger arm lengths (+ 0.6 cm) and leg lengths (+ 1.2 cm), larger relaxed and tensed arm girths (+ 0.6 cm and + 1.1 cm respectively) and larger calf girths (+ 0.85 cm). The fat volume is bigger in the trunk, in 2001 children (+ 1.75 mm, considering the sum of trunk skinfolds) and in the limbs in 1991 children (+ 0.6 mm, considering the sum of limb skinfolds). The body composition analysis revealed that, in spite of children’s higher fat percentage in 1991 (+ 0.3%), the weight of fat mass and fat free mass was bigger in 2001 children (+ 0.4 kg and + 1.4 kg, respectively). Therefore, 2001 children showed higher values of endomorphy and ectomorphy and 1991 children showed higher values of mesomorphy. The above results have only statistical meaning for some ages and variables.

Conclusion

We concluded that Portuguese children in 2001 are more linear (more ectomorphic), but presented larger amounts of fat, accumulated preferentially in the trunk (more endomorphic). On the contrary, children in 1991 are in general more mesomorphic.

References

[1]. Fragoso I. & Vieira F. (2000). Morfologia e Crescimento. Cruz Quebrada, Edições FMH.
[2]. Heath B. H. & Carter J. E. .L (1967). American Journal of Physical Anthropology, 27, 57-74.
[3]. Hoaglin D. et al. (1983). Understanding Robust and Explanatory Data Analysis. John Wiley & Sons, Inc.