Gender differences in the prevalence of low back pain associated with sports activities in children and adolescents: a six-year annual survey of a birth cohort in Niigata City, Japan

Abstract Background This study was conducted to determine gender differences in the relationship between extracurricular sports activities (ECSA) and low back pain (LBP) in children and adolescents. Methods In a cohort analysis of a 6-year birth cohort annual survey, students were followed from the fourth to sixth grades of elementary school (E4–E6; 9–12 years old) through the first to third grades of junior high school (J1–J3; 12–15 years old). All students completed annual questionnaires on ECSA and LBP. The odds ratio (OR) and 95% confidence interval (CI) were calculated to assess the association strength between ECSA and LBP. We also calculated the population attributable fraction (PAF), which was defined as the proportion of students with ECSA-related LBP among all students with LBP. Results ECSA was significantly associated with LBP only in grade J3 among boys (OR: 2.00, 95% CI: 1.47–2.71). On the other hand, among girls, ECSA was significantly associated with LBP in grades E5 (OR: 1.48, 95% CI: 1.00–2.20), E6 (OR: 1.91, 95% CI: 1.33–2.75), and J3 (OR: 1.81, 95% CI: 1.26–2.61). Among boys, PAF was similar in all grades (range, 10–16%), whereas among girls, the PAF varied (− 11 to 29%) and was significantly higher in girls than in boys in grades E5 (19.0% vs. 1.1%, P