Prevalence and risk factors of low back pain among school age children in Iran

Introduction

Recent evidence has demonstrated that low back pain (LBP) is frequent among schoolchildren and youth.^1-4 The reported incidence of back pain in schoolchildren and youth ranges from 7% to 74% in the literature.^5,6Evidence suggests that back pain in childhood and adolescence is a contributory factor for the increased incidence of such complaints in adulthood.^7,8Thus, there appears to be a need to improve the understanding of the risk factors associated with back pain among children and adolescents.

A number of factors may contribute to the development of musculoskeletal complaints in schoolchildren. The risk and protective factors of back pain in children and adolescents can be divided into individual, physical and psychosocial factors.^2-4,9Design of classroom furniture seems to be one of the contributing factors to the development of musculoskeletal pain among schoolchildren.^4,9,10Though not conclusive, there is some evidence that loads carried by schoolchildren (schoolbag or backpack carriage) may be a factor contributing to musculoskeletal complaints among this age group.^11-13, There are also contradictory findings in the literature regarding the association between musculoskeletal symptoms and physical leisure activity and life style factors (i.e. playing sport, watching TV, using a computer, etc.) in schoolchildren with some studies showing a positive association,⁹ while other show no association.⁴Some studies have also noted a significant association between musculoskeletal symptoms and psychosocial factors.^2-4,9,14

Most available data on the prevalence and characteristics of back pain in schoolchildren and adolescents is related to industrialised and developed countries,⁵ while there is limited information in this area in developing and low-income countries. The results of the studies conducted in the developed countries may not necessarily be generalizable to other countries or settings, where the cultural backgrounds or educational systems may be different. Furthermore, most previous studies have not considered the simultaneous effects of various factors (i.e. school-related factors such as classroom furniture and layout design, etc.) on the occurrence of back pain in schoolchildren.^14-16,As a consequence, the effects of risk factors are not consistent and conclusive.

This present study was conducted to evaluate the occurrence of LBP and its contributing risk factors (i.e. demographic and physical leisure activity, school-related, and psychosocial factors) among schoolchildren in a developing country, Iran. The intention was to consider a broader combination of factors (in multivariate context) that influence LBP in school-aged children and also widen the discussion to more countries.

Material and Methods

Results

Discussion

This is one of the largest epidemiological studies so far conducted to evaluate LBP and its various contributing factors in school aged children. It extends the body of knowledge about the issue in this age group in developing countries. Our findings confirm that LBP is frequent in Iranian schoolchildren, which is in line previous reports.^{3,4,14,16,20,21} Individual factors including gender (being female) and family member with back pain were independently associated with the occurrence of LBP. School-related variables such as difficulty in viewing the (black)board, too much homework and carrying a schoolbag for more than 30 min/d, as well as psychosocial factors (high emotional symptoms) were also independently associated with the presence of LBP. Physical activity and leisure time physical activity (including having a job, time spent on sport activities, watching television, using a computer or playing games) and schoolbag weight were not associated with LBP.

Among demographic factors, gender was an independent factor predicting LBP in schoolchildren. Overall, girls had a 50% increased odds of reporting LBP compared with boys. This is similar to several previous reports, which have shown a higher prevalence of LBP in girls than in boys.^3,14,15,20 The higher prevalence rate of symptoms in girls may be attributed to earlier female puberty and its associated hormonal changes²²; while on the other hand, boys may have a tendency to under report or worry less about this problem.⁶It therefore appears that girls are at greater risk of developing LBP as compared with boys. This highlights the need for specifically designed interventional programs for reducing the prevalence of LBP in this group. Moreover, a positive association was found between symptom reporting of family members and LBP among schoolchildren in this study, which is also similar to previous reports.²⁰In contrast, other personal factors including age and BMI as well as physical activity and leisure time physical activity variables (such as having a job and time spent on sport activity, using a computer and playing games) were not found to contribute to any increased or decreased risk for LBP in this study. These findings are in line with some recent reports from developed countries,^4,14which have shown no significant association between physical leisure activity variables and LBP.

As with the schoolbag carriage variables examined in this study, time spent carrying a schoolbag each day was the only factor that was independently positively associated with LBP. This finding is similar to several previous reports,^11,12which have found a positive relationship between time spent carrying schoolbags and the occurrence of LBP. Also, it should be noted that although the schoolbag weight has been described by some authors as one of the possible factors affecting musculoskeletal pain in schoolchildren,¹¹this was not the case in the present study. The lack of association between LBP and schoolbag weight (which was expressed as a percentage of body weight) in our study is consistent with several recent work.^4,6,9,23,24 Given the contradictory findings in the literature, these findings provide additional evidence that the schoolbag weight may not be the only factor associated with back pain amongst schoolchildren and other schoolbag carriage variables such as the time spent carrying schoolbags to and from school each day by schoolchildren should also be taken into account.

It is also of interest to note that inappropriate classroom furniture and lay out design were found to be possible contributing factors to LBP in our study. Difficulty in viewing the (black)board was found to be independently associated LBP. Moreover, several features of classroom furniture including seat height (too low), seat backrest height (too low), seat backrest curvature (too curved/flat), seat depth (too shallow), and desk height (too low) had significant associations with the occurrence of LBP in univariate analyses, but not as independent factors in multivariate analysis. Similar to these findings, Murphy et al⁴ found a positive association between LBP and chair height being too low; while Trevelyan and Legg⁹ reported that LBP was significantly associated with the backrest of the chair being too curved and to the desk height being too low. The results of a recent study among Iranian schoolchildren also showed a considerable mismatch between anthropometric dimensions of children and the existing classroom furniture.²⁵ Taken together, these findings highlight the fact that the classroom furniture and lay out design must be based on the anthropometric needs of schoolchildren to reduce the occurrence of musculoskeletal pain in this group.

With regard to the psychosocial factors, the results of the present study showed that the presence of emotional symptoms (calculated using the SDQ) was independently positively associated with the prevalence of LBP in Iranian schoolchildren. Similar findings have been reported by Watson et al³and Murphy et al⁴among 11–14 years old schoolchildren in the United Kingdom and by Trevelyan and Legg⁹among the schoolchildren with the same age in New Zealand. Other authors have also reported significant relationships between psychosocial factors and the occurrence of back pain in schoolchildren.^2,14Based on these findings, it seems that psychological or psychosocial factors should be given a more prominent role when it comes to evaluating musculoskeletal pain in schoolchildren.

The present study has an advantage that one investigator was present during data collection in order to ensure all schoolchildren were able to understand and answer the questionnaires, and therefore to decrease the likelihood of bias from non-participation. This also prevented observer error as opposed to studies in which there was separate observer for each case (i.e. self-reported or parental-assisted reporting). However, the current findings should be considered in the context of the cross-sectional data collection, and whilst a large dataset was possible, causality cannot be ascertained. It should also be highlighted that the data rely on the accuracy and reliability of self-report. However, as pointed out by several authors, this may be the only measure to understand whether and how the schoolchildren feel any pain or discomfort.²⁶ There are also limitations regarding the generalizability of the findings as the data presented here in this study are from one city of Iran, and thus further studies in other parts of the country and the world are recommended.

Conclusion

In conclusion, this study extends the body of knowledge on LBP to include schoolchildren in developing countries. The main finding of the study was that LBP is frequent in Iranian schoolchildren, which is in line with reports from developed countries. Girls and those who had a family member with back pain were more likely to report LBP. Both physical (i.e. school-related items) and psychosocial variables (i.e. emotional symptoms) influenced the risk for LBP among schoolchildren, which emphasises the need for ergonomic and behaviour-based interventions in order to reduce such complaints in this group. The association of LBP with emotional symptoms was stronger than the association of LBP with physical factors, which highlights the importance of psychosocial interventions in reducing LBP in schoolchildren.

Ethical approval

The study protocol was reviewed and approved by the local ethics review committee of the Tabriz University of Medical Sciences, Iran.

Competing interests

There are no conflicts of interest.

Authors’ contributions

ID involved in the conceptualization and designing of the study. AA involved in the data collection. MA involved in the data analysis and drafting the manuscript.

Acknowledgments

This project was funded by the Tabriz University of Medical Sciences (Grant number: 5/53/511).

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