Background: The child's spine shows changes in posture and balance of its curvatures during growth and musculoskeletal spinal conditions are likely to develop, such as back pain (BP).
Objective: The purposes of this study were (a) to describe the sagittal spinal alignment in a relaxed standing position and (b) to analyze its association with BP among 8 to 12-year-old children.
Methods: This was a cross-sectional study. A total of 731 elementary schoolchildren (379 girls and 352 boys), from 16 Spanish schools, participated. An unilevel inclinometer was used to quantify the sagittal spinal curvatures (thoracic and lumbar) in a relaxed standing position. Sagittal spinal morphotype was analyzed by sex, age, weight, height, and BMI. Children's parents or legal guardians filled in a questionnaire according to the children's responses about the BP suffered in the previous week and the preceding year.
Results: The mean angular value of thoracic kyphosis was 36.08 ± 8.99∘ and significantly higher in males than in females (p= 0.036). In contrast, the mean value of lumbar lordosis was 32.11 ± 7.46∘, being higher in females than in men (p< 0.01). The thoracic curve tends to increase by age (p= 0.003). Children who had low back pain (LBP) in the previous week had a significantly greater lumbar curve (35.88 ± 8.20∘) than those who did not have LBP in the preceding week (32.24 ± 7.30∘). The angle for lumbar curvature was a small predictor of LBP occurrence in the assessed children (OR = 1.082 [small]; 95% CI = 1.009-1.160, p= 0.028).
Conclusions: To conclude, almost 3/4 of the students were classified with normal thoracic kyphosis; however, 27.36% of the students had thoracic hyperkyphosis. Lumbar hyperlordosis was identified in 9.05% of the students, and was 2.5 times more frequent in girls. The lumbar curvature was a small predictor of LBP occurrence in the assessed children and the angle of lumbar curvature that most accurately identified individuals at risk of developing LBP was determined to be 33∘. The results of this study indicate the need to assess sagittal spinal curvatures at school during development ages.
Keywords: Kyphosis; children; inclinometer; lordosis; spinal imbalance; spine.