Researchers Fiona C. Trevelyan & Stephen J. Legg set out to investigate low-back pain in New Zealand school aged children between the ages of 11 and 14 years. Their results may come as a surprise to some, and may be cause for concern as the prevalence of computers and hand-held devices grows among the younger population.
In their brief introduction, the authors note several key points of interest:
- back pain in adults receives considerable attention, but until recently, comparatively little has been done to understand its prevalence and characteristics in children;
- back pain among children was historically considered an anomaly, until recent research has indicated otherwise;
- more recent studies have shown reports of back pain beginning in early childhood, and non-specific low back pain (LBP) reports are high;
- among adults, reports of previous history of back pain is a strong predictor of future LBP;
- a large proportion of LBP sufferers report the first onset of back pain in their early teenage years or adult life;
- at least one previous study has focused on backpacks, and numerous studies focus on "the mismatch between school furniture and student body size" as potential contributions to muscuoloskeletal discomfort;
- where back pain has been studied, differences in experimental methods and definitions lead to different results (one study reports back pain prevalence in children as between 20% and 51%, while another reports it as 35%).
A detailed description of the study is available in the original article, available at no charge at the time of this writing from the reference and link cited below. Key methodology points include:
- all school children surveyed in this study were located within a 20 km radius of the Palmerston North region of New Zealand and included a mix of rural and urban schools;
- 7 out of the 10 applicable schools in the region agreed to participate;
- participation by individual students was voluntary and required parental consent;
- of the resulting 1331 eligible children, only 245 actually participated;
- participants were grouped for comparison in either "Form 1" or "Form 2", also known as "years 7 and 8" by New Zealanders;
- Form 1 participants included 71 girls and 51 boys (mean age = 11.54 yrs, standard deviation = 0.33 yrs);
- Form 2 participants included 62 girls and 56 boys (mean age = 12.53 yrs, standard deviation = 0.33 yrs);
- self-report questionnaires were based on those developed and previously tested for reliability and validity by the Epidemiology Research Unit at the University of Manchester, UK and the Robens Centre for Health Ergonomics at the University of Surrey, UK;
the questionnaire sought to measure "demographic characteristics, back pain history, psychosocial parameters, school and leisure activities and family characteristics," and included:
- a chair feature checklist to obtain information about furniture suitability and comfort;
- a "Strengths and Difficulties Questionnaire (SDQ)" psychosocial assessment;
2 separate questions to assess the prevalence of spinal pain, including:
- (1) a body pain region Nordic manikin map, either in last 7 days or last month, how long the pain lasted (hrs/day), and its intensity (3 point scale) for each region; and
- (2) a question pertaining to low back pain (LBP) only: "In the last month, have you had LBP which lasted for one day or longer?"
- LBP-related disability was assessed using "the Hanover Low Back Pain Disability Questionnaire";
- a statistically significant result was 5% (or p = 0.05, meaning there is only a 1 chance in 20 (or 5 in 100) this finding could have happened by coincidence).
The data was collected, in 2002, over a 6 week period. The children were measured for height and weight, and the questionnaire took about 20 minutes to complete.
A detailed description of the study is available in the original article, available at no charge at the time of this writing from the reference and link cited below. Some key results include:
- Form 2 children (older) reported significantly more low back pain (LBP) than Form 1 (younger) children;
- no significant gender differences were found for LBP reports;
- a significant relationship between ever having LBP and higher weight;
- a significant relationship between ever having LBP and higher Body Mass Index (BMI);
- 58% of the total reported some spinal pain within the past month;
- 31% reported the pain to be in only 1 region if the spine, most commonly in the low back, followed by the neck, followed by the upper back;
- 28% of the total reported pain in more than one spinal region, most commonly in the low back and neck regions;
- of the 27% that reported back pain in the last month, LBP was reported as more severe;
- 48% reported having LBP during their lifetime, approximately 25% of those reported it as being when they were between 10 and 12 yrs old;
- there was a strong significant relationship between those reporting LBP at some point in their life and their report of having neck or upper back pin within the last month;
- 69% of the of the 27% who reported LBP that lasted longer than 1 day noted that a family member also suffered from the same condition, and 43% of those reported having sought treatment, and of those, more than twice as many did so for back pain than for neck pain;
- 98% of those reporting LBP in the last month also reported difficulties with certain tasks, including standing on line/queue (55%), sitting up in bed (50%), sports activities (49%) and carrying school bags (47%).
The researchers noted concern that their results differed from previous studies. They recognize that different methodologies, different questionnaire design and survey techniques, etc. could explain these differences, and suggest closer cooperation between researchers and studies in the future. Even with some differences, the authors report their results as consistent with the results of UK children studies. Further,
- Surveys and self-reporting issues: it's not clear exactly how the children were instructed and what other experimenter and peer student interactions may have taken place, but it is conceivable that these factors could influence questionnaire responses. As with any self-reporting survey, a host of influences and psychosocial issues can affect questionnaire response and study outcomes; and
- a population from a single region in a single country may make it difficult to extrapolate these results to a wider population of children;
- a relatively small and self-selected sample size (245 volunteer participants out of an available pool of 1331), although the researchers felt their methods minimized this potential effect.
What Might This Mean to Ergonomists?
First, we need to recognize that this study began in 2002, wasn't published until 2010, and wasn't reviewed here until 2012, some 10 years later. This is not a comment on the researchers, but does illustrate how long it sometimes takes for scientific studies to "reach the light of day." We also need to recognize the study limitations described above. However, with these concerns in mind, this is still valuable information and contributes to a growing body of evidence that spinal pain may be on the rise in children, which could translate into increased prevalence and severity later in life.
The researchers highlight their finding that low back and neck pain were equally common in their study, but that low back pain has the potential to be longer lasting, more severe, and is more likely to interfere with life activities. The implications and motivations for this research include the mismatch between school furniture and children, as well as activities like carrying heavy backpacks. However, another concern that comes to my mind, and is in part why I selected this for review, is the potential effect of the increasing use of computers and hand-held devices, including among children. Hand-held devices have been implicated in growing reports of neck pain among adults (e.g., see Study: Tablet Use Causes Significant Head and Neck Flexion). What might be the effect of these devices on children?
What are the implications for the future, and how will ergonomists play a role in improving that future by doing what we do best — improving the interface between people, including kids, and technology?
Fiona C. Trevelyan & Stephen J. Legg, The prevalence and characteristics of back pain among school children in New Zealand, Ergonomics, 53(12), pp. 1455-1460, DOI:10.1080/00140139.2010.528455.
At the time of this writing, this article was available at no charge from: http://www.tandfonline.com/doi/full/10.1080/00140139.2010.528455
This article originally appeared in The Ergonomics Report™ on 2012-05-29.