The largest population study to investigate low back pain (LBP) and mechanical and psychosocial factors together in schoolchildren has suggested that it may be a marker for distress.

A self completion survey and other measurements were completed for 1376 children aged 11–14 years. One month prevalence of LBP was significantly higher for girls than boys (28% v 19%) and for both with age (girls 18% v 34% at ages 11 and 14 respectively; boys 14% v 25%). Multivariate analysis showed that children with conduct or emotional problems had up to 2.4 times the odds of LBP and those with minor ailments like persistent headache and sore throat had 1.4–1.9 times the odds. Part time working also increased the odds but not apparently because of carrying or lifting heavy weights. Physical activity, body mass index (BMI), and weight of school bag were not important. In the whole group the prevalence of LBP increased stepwise with each significant risk factor—from 12% for children with none to 17% for those with all six.

The cross sectional study was based on schools in two areas of northwest England with a general population of mixed socioeconomic profile in rural and urban areas. Thirty nine schools contributed 1496 children, 1376 of whom completed questionnaires. BMI and bag weight were also recorded, and all data were collected during one school year.

LBP is a recognised problem in children, but evidence from separate studies has variously implicated physical load and adverse psychosocial factors.