Improving Schoolchildren's Knowledge of Methods for the
Prevention and Management of Low Back Pain:
A Cluster Randomized Controlled Trial

This section is compiled by Frank M. Painter, D.C.
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FROM:   Spine (Phila Pa 1976). 2011 (Apr 15);   36 (8):   E505–512 ~ FULL TEXT

Francisco Kovacs, MD , PhD, Malén Oliver-Frontera, BS, María N. Plana, MD, Ana Royuela, MSc, Alfonso Muriel, MSc, Mario Gestoso, M.D, and the Spanish Back Pain Research Network

Departamento Científico.
Fundación Kovacs,
Palma de Mallorca. Spain.

STUDY DESIGN:   Cluster randomized controlled trial.

OBJECTIVE:   To evaluate the effect of a very simple education campaign among community-dwelling 8-year-old schoolchildren.

SUMMARY OF BACKGROUND DATA:   Information has a positive effect on low back pain (LBP) prevention and management. There is sparse evidence on the feasibility and effectiveness of education campaigns focusing on LBP among young schoolchildren.

METHODS:   A stratified random sample of 12 schools was randomized to an intervention and a control group. Eight-year-old schoolchildren from these schools were given a questionnaire on LBP prevention and management at baseline, and 15 and 98 days later. On day 8, teachers in the intervention group gave the schoolchildren a Comic Book of the Back, while no intervention was carried out in the control group. After adjusting by possible confounders, generalized estimating equations (GEE) models were developed to calculate the probability of "success" (a score over 80% of the maximum possible one).

RESULTS:   Six schools (231 children, 46.5%) were assigned to the control group, and 6 (266 children, 53.5%) to the intervention one. At baseline, the percentage of correct answers was above 73% in both groups, with 8 as a median total score in the control group and 7 in the intervention group. GEE showed that the odds ratio for success in the intervention group, when compared with the control group, was 1.61 (95% CI: 1.03-2.52, P = 0.038).

CONCLUSION:   The handing out of a Comic Book of the Back slightly improves children's knowledge of appropriate methods for the prevention and management of LBP, and the effect remains significant 3 months after intervention.

Key words   : education campaign, low back pain, schoolchildren, cluster randomized controlled trial.

From the Full-Text Article:


Short education programs and campaigns that correct erroneous beliefs are effective for prevention and treatment of low back pain (LBP) among the general population, workers, the elderly, and patients. [1–7] Current evidence-based guidelines for prevention and treatment of LBP recommend such programs. [8–10] The Back Book is a short booklet designed f or this purpose. [1–3]

Suffering from back pain in childhood or adolescence increases the risk of having it as an adult, [11] and some risk factors associated with back pain in childhood have been identifi ed. [12–17] Hence, prevention campaigns and health education programs should include children. Since it has been shown that from the age of 13 years, the prevalence of back pain is similar to that of adults, [12–17] these campaigns should be aimed at children younger than that age, [18–22] and need to include material that is understandable at these ages. For this purpose, a very short booklet with messages consistent with those in the Back Book was designed in a comic book format. Its main content included the following: back pain is usually not due to any serious injury; physical activity and exercise have a positive effect on back pain for both prevention and treatment; and if back pain occurs, bed rest should be avoided and the highest possible degree of activity should be maintained. In addition, the comic book recommended that backpacks should not surpass 10% of body weight [23–28] and that children involved in competitive sports follow the advice of their coaches and physicians strictly. [12–20] The Comic Book of the Back is available in Spanish from the authors.

A campaign consisting of the distribution of the Comic Book of the Back among young schoolchildren was launched in September 2006 and endorsed by Spanish national medical, health, and educational authorities. Within the campaign, the Comic Book of the Back was made freely available through the Internet and it was also distributed in the schools in the areas where the regional authorities decided to do so. [29] With slight organizational changes, the campaign was repeated at the beginning of the academic course in September 2007. The objective of this study was to evaluate the effect that the handing out of the Comic Book of the Back had on the knowledge of measures to prevent and manage LBP among 8-year-old schoolchildren.


This was a cluster randomized controlled clinical trial, with a 3-month follow-up, in which randomization and analysis were blind.


The study population was constituted of all 8-year-old schoolchildren in Majorca, a Spanish island in the Mediterranean Sea with a population of approximately 850,000. An 8-year old schoolchild was defined as one who has reached or will reach that age throughout the school year in which the study took place.

The study sample was composed of all 8-year-old children attending the schools that were selected to participate. The only exclusion criterion was not attending class on the day in which subjects were recruited.

All schools in the island of Majorca were listed and classified in six strata, according to the type of school (public, private or concerted—the latter, run with public funds and managed according to government-issued criteria, but privately owned) and their location (urban, rural, the latter defined as located in cities with ≤10,000 inhabitants). There was no school in the “private, rural” stratum. A stratified random sample of the schools was selected, and confi rmation of their agreement to participate in the study was taken from all the schools.

Sample size was established at 12 schools (6 public, 4 concerted, and 2 private), assuming that at the end of the follow-up, the proportion of schoolchildren with an appropriate knowledge of the prevention and management of back pain would be 80% in the control group and 90% in the intervention group, with a median cluster size of 38 children per school (i.e., a total number of 456 schoolchildren), an intraclass correlation coefficient of 0.10, a type I error of 0.05 and a type II of 0.20. “Appropriate” knowledge was defined as having a score higher than or equal to 80% of the maximum possible score in the questionnaire that was answered on day 98.

The study was supported by the regional education authorities and was approved by the institutional review board of the Majorcan Health Authorities and the District Attorney’s offi ce for children’s affairs. According to the Spanish laws, the characteristics of this study made it unnecessary to ask for parental written informed consent.


Randomization was performed at the cluster level, with the unit of randomization and analysis being the school.

Randomization was performed according to the table of random numbers of Moses and Oakford. [30] Sealed opaque envelopes were prepared. In the front, Arabic co rrelative numbers were indicated, and each envelope contained the number in the corresponding order in the table of random numbers. The starting point where the tables began to be read was randomly determined just before the process started.

Once a school in a given stratum accepted to participate in the study, the envelope corresponding to the order in which its acceptance had been received was opened by a member of the administrative staff who was unaware of the number it contained. Assignment to control or intervention groups was determined by the number from the table of random numbers contained in the envelope.


No intervention was undertaken in the control group, in which only assessments were carried out. In the intervention group, the intervention consisted of the teacher handing out a Comic Book of the Back to each pupil in the class. Teachers were not asked to discuss the content of the comic book in class. Intervention took place in the different schools between October 20, 2008, and November 7, 2008.

Each school was supplied with the Comic Book of the Back in the language(s) in which it provided education: Spanish, English, or Majorcan (a variation of Catalan, a regional language used in some areas in Northeast Spain).

For ethical reasons, the children in schools from the control group were given the Comic Book of the Back at the end of the study, after having completed their participation in it.

      Outcome Assessments

Outcome was assessed through a questionnaire, which was handed out 1 week before, 1 week after, and 90 days after the intervention.

One week before the Comic Book of the Back was given to the children in the intervention group, teachers handed out a questionnaire that the children filled out, and retrieved it. The questionnaire was written in the language(s) the school used, and contained 10 statements focusing on ways to prevent or manage back pain (Tables 1 and 2). The children were asked to indicate which statements were true and which were false. For ethical and legal reasons, students were identified by numeric codes instead of their names.

At follow-ups that took place 7 and 90 days after intervention (i.e., 15 and 98 days after the first assessment), children were given the same questionnaire. On days 1 and 15, the children were unaware that they would be given the same questionnaire again.

The children were not aware of the existence of other groups (control or intervention) in other schools. The teachers could obviously not be blinded with respect to whether the children were or were not given the comic book. They were instructed not to give away the correct answers, not to help the children answer the questionnaire, and not to interfere with the children’s responses in any way, but to simply hand out the questionnaires on the appropriate days, ensure that the children answered all of the questions, and place them in a special container which one of the assistants from the study’s coordination offi ce retrieved no later than an hour after completion.

Data were entered in a database at a coordination-centralized offi ce by two administrative assistants who double-checked that the data entered coincided with the questionnaire scores. Those administrative assistants were blinded to the school’s assignment to the intervention or control group.

Data on sex, type of school (public, private, or concerted), location (urban or rural), and language(s) used in the school were collected. Since subjects could not be identifi ed by their name, data on history of previous LBP episodes could not be gathered from their families. No data were found on the reliability of 8-year-old subjects’ report on history of LBP. Therefore, history of LBP was not gathered.


Analysis was done by a group of statisticians who were not involved in the conduct of the study and worked in a different region of Spain. They were given the codes to identify schools from each group but were blinded as to which group corresponded to control or intervention.

Data were analyzed at the individual and cluster levels. At the individual level, absolute and relative frequencies were used for categorical variables. Medians and interquartile ranges (IQR) were used for “global score” because it was not normally distributed. At the cluster level, medians and interquartile ranges of the statistics used at the individual level were calculated.

The primary outcome of the study was the “success” variable, defined as having a score higher than or equal to 80% of the maximum possible score in the questionnaire that was answered at the last follow-up assessment, on day 98. The intraclass correlation coefficient was estimated by 1-way ANOVA for the difference between scores at baseline and 98 days. [31] At the individual level, the Mann-Whitney U test was used to compare the evolution of the global score between groups.

Because of the cluster design, to estimate the effect of the dependent variable, generalized estimating equation (GEE) models were used to adjust for possible confounding factors.

The maximal model included the following variables: sex, type of school, language (Catalonian, Catalonian and Spanish, English and Spanish), location of the school (urban/ rural), and baseline score. A backward strategy was used so that a variable was considered to be a confounder when its removal from the model resulted in a change in the effect size of 10% or more. [32] The variable “language” was eliminated from the maximal model due to problems with collinearity.

SPSS (v. 17.0) and STATA (v. 10.0; Stata corp., College Station, TX) statistical programs were used for the analysis.


Twelve schools were randomly selected and agreed to participate. They schooled 587 eight-year-olds, 574 (97.8%) of whom attended class on the day in which recruitment took place and were included in the study. Thirty-two children (5.6% of those included) missed the 15-day follow-up, and other 45 (7.8%) the 98-day follow-up assessment. Among the 497 children who completed follow-up (86.6% of those included), 231 (46.5%) were studying in schools allocated to the control group and 266 (53.5%) to the intervention group (Figure 1). Tables 1 and 2 show the baseline characteristics of the schoolchildren, at both the individual and cluster levels.

For both groups, the percentage of correct answers to the questionnaire before the intervention (baseline) was above 73%, with 8 as a median total score for the control group and 7 for the intervention group (Table 2).

At the individual level, the median (IQR) increases in score, within the control and intervention groups, were, respectively, on day 15: 0 (–1;1) versus 1 (0;2) (P < 0.001). On day 98: 1 (0;2) versus 1 (0;3) (P < 0.001) (Figure 2).

Table 3 shows the evolution of the median global scores for each group, at both the individual and cluster levels. The cluster effect estimated by the intraclass correlation coefficient was 0.33.

Results from the GEEs had to be adjusted for baseline score and type of school, whereas sex, language, and school location did not influence results. Results from GEE showed that the odds of “success” for the intervention group was 1.61 (95% CI: 1.03–2.52) times higher than that for the control group (P = 0.038) (Table 4). Questions responsible for the better evolution of the score in the intervention group were N° 1, 3, 4, and 9, which relate to the effect of bed rest, sitting, physical activities and sport, on back’s pain prevention and management (Tables 1 and 2).


In this study, the intervention consisted in handing out comic books in the classrooms of 8-year-old schoolchildren. This simple education program had a positive effect that lasted for at least 3 months.

Baseline score in both groups was high (Table 1), probably because of previous campaigns in the geographic setting where it was conducted. Should that be the case, the intervention used in this study might have a greater impact in settings where previous campaigns have not been undertaken. The high baseline score in both groups did not leave much room for improvement in the intervention group. This may account for the improvement in the intervention group being small (OR = 1.61, but in terms of risk ratio, according to a baseline probability of 50%, it is equal to 1.25 [95% CI: 1.01–1.43]). However, this improvement is statistically significant and, in the context of a public campaign, small effects deriving from cheap and easyto- generalize interventions, are valuable.

Approximately 98% of the children who were eligible to participate in this study were included, and approximately 87% of those included completed follow-up (Figure 1). This suggests that generalizability of these results to the schoolchildren in Spain is not a concern. However, this study has a number of limitations. Follow-up could not be longer because Spanish laws on privacy make it virtually impossible to gather the names of the minors. Therefore, a number code was used to identify each subject. Since that code was valid only during the current academic year, follow-up had to be completed during that period, which in fact lasts 9 months. Taking into account the time needed to randomize schools, ensure that they were willing to participate, and distribute the booklets, 3 months was the maximum feasible follow-up period. Previous studies on health education programs for prevention of back pain among elementary schoolchildren have shown that their effects last up to 1 year. [19, 21] However, further studies should assess the duration of the effect of the intervention implemented in this study. If the effects of this campaign were short-lived, its simplicity and low cost would make it feasible to repeat it periodically.

Legal limitations made it unfeasible to gather subjects’ history of LBP from their family and associate it with the corresponding subject, since it was impossible to identify their names. Therefore, in order to prevent bias from advice received during potential previous LBP episodes, it was decided to recruit 8-year-old subjects, who were likely to have not suffered from LBP. [11–22, 28] As a consequence, the intervention, the outcomes, and the follow-up period were designed for subjects of that age. Since self-reports on LBP at that age were considered to be potentially unreliable, no data on LBP history were gathered. Further studies should assess if previous history of LBP influences the effect of the intervention tested in this study, either because of the experience itself or as a proxy for having received advice and treatment.

Another consequence of having recruited very young subjects is that only knowledge could be assessed, as opposed to its actual impact on LBP prevention or management. However, most of the increase in knowledge was in the area of active management, which among adults leads to a clinically relevant effect. [1–7] Therefore, it is possible that it also has a positive effect in children, and further studies should assess this.

In this study, teachers were only asked to hand out the comic book and not to discuss it in class. Nevertheless, it is possible that some did so, which would be a “cointervention” increasing the effect of the intervention. However, this would probably also occur in practice if this measure were to be generalized in the academic environment and can be seen as inherent to the intervention itself. Further studies might assess the effect of this intervention outside this environment. However, the school may be a suitable place to implement cheap interventions aiming at young schoolchildren for the prevention of prevalent health conditions, especially when they can be implemented without any significant loss of academic time.

Previous randomized clinical trials have shown that an educational program similar to the one implemented in this study improves LBP, LBP-related disability, and quality of life, and that these effects are not mediated by the improvement in psychological variables, [2, 3] which in fact have shown to have no relevant influence on LBP, LBP-related disability, or quality of life in Spanish subjects. [2, 3, 33–35] In these trials, the positive effects of education were attributed to direct promotion of physical activity and increased knowledge of evidence-based methods to prevent and manage LBP. [2, 3] Therefore, it is likely that this increased knowledge has positive effects also in young schoolchildren, most of whom had not undergone LBP and were likely not to have strong previous beliefs on how to prevent or manage it.

Positive results from this study suggest that it may be advisable to generalize this campaign to larger populations of that age, and that for very young children, a “comic book” format, in which messages are conveyed in simple terms and with drawings that catch the children’s attention, is probably an appropriate way to educate children at such an early age on preventive mechanisms.

Key Points

  • This cluster randomized controlled trial was conducted to assess the effect of handing out the Comic Book of the Back to community-dwelling 8-year-old schoolchildren. The “comic book of the back” is a very simple booklet promoting active management and prevention for low back pain (LBP).

  • Six schools (231 children) were randomly assigned to the control group and another 6 (266 children) to the intervention one. No intervention was carried out in the control group, while the Comic Book of the Back was handed out to the children in the intervention one.

  • The handing out of the Comic Book of the Back increased the children’s knowledge of methods for the prevention and management of LBP. This effect was small but significant, and it remained 3 months later.


The regional education authority of the Balearic Islands provided institutional support for the development of this study.


  1. Burton AK, Waddell G, Tillotson M, et al.
    Information and advice to patients with back pain can have a positive effect.
    Spine 1999;24:2484–91.

  2. Kovacs F, Abraira V, Santos S, et al.
    A comparison of two short education programs for improving low back pain–related disability in the elderly.
    A cluster randomized controlled trial.
    Spine 2007;32:1053–9.

  3. Albadalejo C, Kovacs F, Royuela A, et al;
    Spanish Back Pain Research Network. The efficacy of a short education program and short physiotherapy program
    for treating low back pain in primary care.
    Spine 2010;35:483–96.

  4. Buchbinder R, Jolley D, Wyatt M.
    2001 Volvo award winner in clinical studies:
    effects of a media campaign on back pain beliefs and its potential influence on management
    of low back pain in general practice.
    Spine 2001;26:2535–42.

  5. Buchbinder R, Jolley D, Wyatt M.
    Population based intervention to change back pain beliefs and disability: three part evaluation.
    BMJ 2001;322:1516–20.

  6. Buchbinder R, Jolley D.
    Effects of a media campaign on back beliefs is sustained three years after its cessation.
    Spine 2005;30: 1323–30.

  7. Waddell G, O’Connor M, Boorman S, et al.
    Working Backs Scotland: a public and professional health education campaign for back pain.
    Spine 2007;32:2139–43.

  8. Burton AK, Balague F, Cardon G, Eriksen HR, Henrotin Y, Lahad A, Leclerc A, Muller G, van der Beek AJ.
    COST B13 Working Group on Guidelines for Prevention in Low Back Pain.
    Chapter 2. European Guidelines for Prevention in Low Back Pain
    European Spine Journal 2006; 15 (suppl 2): S136-S168

  9. van Tulder M, Becker A, Bekkering T, et al; On behalf of the COST B13 Working
    Group on Guidelines for the Management of Acute Low Back Pain in Primary Care.
    Chapter 3. European Guidelines for the Management of Acute Nonspecific Low Back Pain in Primary Care
    European Spine Journal 2006 (Mar); 15 Suppl 2: S169–191

  10. Airaksinen O, Brox JI, Cedraschi C, Hildebrandt J, Klaber-Moffett J, Kovacs F, et al.
    Chapter 4. European Guidelines for the Management of Chronic Nonspecific Low Back Pain
    European Spine Journal 2006 (Mar); 15 Suppl 2: S192–S300

  11. Harreby M, Neergaard K, Hesselsoe G, et al.
    Are radiologic changes in the thoracic and lumbar spine of adolescents risk factors for low back pain in adults?
    Spine 1995;20(21):2298–302.

  12. Kovacs FM, Gestoso M, Gil del Real MT, et al.
    Risk factors for non-specific low back pain in schoolchildren and their parents: a population based study.
    Pain 2003;103:259–68.

  13. Balagué F, Dutoit G, Waldburger M.
    Low back pain in schoolchildren.
    Scand J Rehabil Med 1988;20:175–9.

  14. Balagué F, Nordin M, Skovron ML, et al.
    Nonspecific low back pain among schoolchildren: a field survey with analysis of some associated factors.
    J Spinal Disord 1994;7:374–9.

  15. Balagué F, Skovron ML, Nordin M, et al.
    Low back pain in schoolchildren: a study of familial and psychological factors.
    Spine 1995;20:1265–70.

  16. Brattberg G.
    The incidence of back pain and headache among Swedish schoolchildren
    Qual Life Res 1994;3:S27–31.

  17. Salminen J.
    Low back pain and disability in 14 year old schoolchildren.
    Acta Pediatr 1992;81:1035–9.

  18. Heyman E, Dekel H.
    Ergonomics for children: an educational program for elementary school.
    Work 2009;32 (3):261–5.

  19. Geldhof E, Cardon G, De Bourdeaudhuij I, et al.
    Back posture education in elementary schoolchildren: stability of two-year intervention effects.
    Eura Medicophys 2007;43(3):369–79.

  20. Geldhof E, Cardon G, De Bourdeaudhuij I, et al.
    Effects of a two school- year multifactorial back education program in elementary schoolchildren.
    Spine 2006,1;31(17):1965–73.

  21. Cardon G, De Bourdeaudhuij I, De Clercq D.
    Knowledge and perceptions about back education among elementary school students, teachers, and parents in Belgium.
    J Sch Health 2002;72(3): 100–6.

  22. Cardon GM, De Clercq DL, De Bourdeaudhuij IM.
    Back education efficacy in elementary schoolchildren: a 1-year follow-up study.
    Spine 2002,1;27(3):299–305.

  23. Negrini S, Negrini A.
    Postural effects of symmetrical and asymmetrical loads on the spines of schoolchildren.
    Scoliosis 2007; 2:8.

  24. Negrini S, Carabalona R.
    Backpacks on! Schoolchildren’s perceptions of load, associations with back pain and factors determining the load.
    Spine 2002;27(2):187–95.

  25. Negrini S, Carabalona R, Sibilla P.
    Backpack as a daily load for schoolchildren.
    Lancet 1999;354(9194):1974.

  26. Sheir-Neiss GI, Kruse RW, Rahman T, et al.
    The association of backpack use and back pain in adolescents.
    Spine 2003;28(9):922–30.

  27. Mackenzie WG, Sampath JS, Kruse RW, et al.
    Backpacks in children.
    Clin Orthop Relat Res 2003;(409):78–84. Review.

  28. Limon S, Valinsky LJ, Ben-Shalom Y.
    Children at risk: risk factors for low back pain in the elementary school environment.
    Spine 2004,15;29(6):697–702.

    accessed July 14, 2009.

  30. Moses LE, Oakford RY.
    Tables of Random Permutations.
    Stanford: Stanford University Press; 1963.

  31. Fleiss JL.
    The Design and Analysis of Clinical Experiments.
    New York: John Wiley & Sons; 1986.

  32. Kleinbaum DG, Kupper LL, Muller KE.
    Applied Regression Analysis and Other Multivariable Methods. 2nd ed.
    Boston, MA: PWSKent; 1988.

  33. Kovacs F, Abraira V, Cano A, et al;
    Spanish Back Pain Research Network. Fear Avoidance Beliefs do not influence disability and quality
    of life in Spanish elderly subjects with low back pain.
    Spine 2007;32:2133–8.

  34. Kovacs FM, Noguera J, Abraira V, et al.
    The influence of psychological factors on low back pain-related disability in community-dwelling older persons.
    Pain Med 2008;9(7):871–80.

  35. Kovacs FM, Muriel A, Abraria V, et al, and the Spanish Back Pain Research Network.
    The influence of fear avoidance beliefs on disability and quality of life is sparse
    in Spanish low back pain patients.
    Spine 2005;30(22):E676–82.


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