Study design: A prospective cohort study in adolescents aged 7 to 19 years.
Objective: To evaluate whether persistent overweight increases the risk of low back pain (LBP) among adolescents.
Summary of background data: Overweight and LBP are common health problems in adolescents. Their relationship is still controversial among adolescents, as well as among adults.
Methods: The study population, the Oulu Back Study, was drawn from the Northern Finland Birth Cohort 1986. The final study sample included 1660 adolescents (56% females). The subcohort of 786 subjects (57% females) was used in the analysis of waist circumference. The association between the area under the curve of body mass index from 7 to 16 years, and from 16 to 18 years, and area under the curve of waist circumference from 16 to 19 years, and LBP during the past 6 months was evaluated separately for incident (reporting LBP at 18 or 19 yr but not at 16 yr) and persistent LBP (reporting LBP at 16 and 18 yr or 19 yr). Relative risks (RR) and their 95% confidence intervals (95% CI) were adjusted for smoking, leisure time physical activity, and family socioeconomic status at 16 years and stratified by sex.
Results: Body mass index from 16 to 18 years among girls and body mass index from 7 to 16 years among boys predicted incident LBP at 18 years (girls: RR, 1.09; 95% CI, 1.01-1.18; boys: RR, 1.15; 95% CI, 1.00-1.32). Among boys, waist circumference from 16 to 19 years was also associated with incident LBP (RR, 1.16; 95% CI, 1.02-1.32). Overweight was not associated with persistent LBP.
Conclusion: In this population-based cohort study, persistent overweight slightly increased the risk of incident LBP, but the time period during which overweight was related to incident LBP differed between sexes.
Level of evidence: 2.