Profiling schoolchildren in pain and associated demographic and behavioural factors: a latent class approach.

Musculoskeletal pain in adolescence is common and individuals frequently report pain in different sites. However, statistical analysis is often limited to considering one or a few pain sites. In this study latent class analysis was used to classify individuals into latent classes in terms of their patterns of endorsing ten musculoskeletal sites. Previously established covariates of musculoskeletal pain in adolescents were then assessed across emergent latent classes. The study was a cross sectional survey of adolescents attending post-primary schools in England. A total of 679 took part in the study with an age range from 11 to 14 years. Pain was operationalised as the occurrence of pain for one day or more in the past month. Schoolchildren self-reported on the incidence of pain aided by a nordic manikin. A three-class model emerged as the best fit. Classes were labelled 'Pain free' (63.4%), 'Neck and back' pain (28.2%) and 'Widespread' pain (8.4%). The 'Widespread' pain class was significantly related with Age (OR=1.79; 95%CI 1.24-2.57), Sex (OR=0.35, 95%CI 0.16-0.79), bag weight to body weight (OR=1.12, 95%CI 1.03-1.22), bag carrying method (OR=2.08, 95%CI 1.08-3.97), Schoolwork difficult (OR=2.78, 95%CI 1.27-6.07), and headaches (OR=2.13, 95%CI 1.65-2.76). While Strengths and Difficulties Questionnaire scores (OR=1.05, 95%CI 1.01-1.11), and Headaches (OR=1.78, 95%CI 1.39-2.26) were significant for the 'Back and neck' class. It is suggested that research should seek to identify typical pain profiles for adolescents, rather than concentrating on specific pain sites since some risk factors may be obscured or inflated by inappropriately amalgamating or segregating pain sites.