First growth reference curves for Tunisian children and adolescents

A growth chart is a powerful graphical tool displaying children's growth patterns. The aim of this study was to develop growth reference curves appropriate for Tunisian children. The collection of data from this cross-sectional study was conducted on 4358 healthy subjects (2182 girls and 2176 boys) in three pediatric centers and 15 schools. Smoothed growth curves were estimated using the LMS method. The smoothed percentile curves for height, weight, sitting height (SH), and leg length (LL) increase rapidly during the 1st years of life and then progress slowly until 18 years. However, the sitting height-to-height ratio (SHTHR) curves decrease sharply before the age of 4 and then stabilize in both sexes. In addition, the comparison between boys and girls indicated that the values are very similar at most ages. Except during puberty, the values in boys increase (P<0.0001) for the weight, height, SH, and LL parameters and decline (P<0.0001) in the SHTHR compared to the values in girls. The growth rate curves presented two remarkable velocity peaks: the first appears during the 1st years of life and the second at puberty. Height gains at the last stage of growth (puberty) are around 15.45% of final height for boys and 15.52% for girls. This study showed a number of discrepancies for certain age groups when comparing the median weight and height values with those of the World Health Organization, the National Center for Health Statistics, and Algerian references in both sexes. Conclusion: The smoothed percentile curves for weight and height will be useful to access the general growth of Tunisian children. Furthermore, the SH, LL, and SHTHR curves can be used to monitor body proportions during childhood.