Sex-related differences in the sagittal plane spinal angles in preschool and school-age children

Abstract Study aim: The study aimed to assess the differences in the magnitude of the anterior-posterior spinal curvatures depending on sex in children aged 5 and 9 years. Material and methods: This prospective longitudinal observational study included 67 children (29 girls and 38 boys) in pre-school-age and school-age phases (the first examination at 5 years old and the second examination at 9 years old). Measurements of body weight and height were recorded. The computerized assessment of body posture was performed with the photo-grammetric method (MORA 4 Generation). The normality of the distribution of variables was assessed with the Shapiro-Wilk test. The Mann-Whitney U test was used to analyze the differences between the sexes in terms of body posture parameters and somatic parameters. Results: There were no statistically significant sex-related differences in the values of parameters of the anterior-posterior spinal curvatures in 5-year-old children. In the group of 9-year-old children in the angle of lumbar lordosis, a significant difference between the sexes was found (U = 387.00, p < 0.05). Girls aged 9 had a significantly higher mean value of the angle of lumbar lordosis than boys at the same age (p < 0.05). Conclusions: A sex-related difference was found in the magnitude of lumbar lordosis in school-age children. Understanding the gender differentiation of lumbar lordosis is the first step towards explaining the wide variability of normal lumbar lordosis in adults and the developmental and biomechanical differences between male and female lumbar spines.