INTRODUCTION

Musculoskeletal pain is a common condition in children and adolescents, with an estimated prevalence between 4% and 40%, representing an important public health problem in this age group. Data from the Global Burden of Disease Study indicate that cervical and lumbar spine pain are among the leading causes of years lived with disability (YLDs) in individuals aged 10–19 years, affecting approximately 2.4 million people worldwide. In addition to the immediate functional impact, this type of pain is associated with a higher risk of symptom persistence and chronicity in adulthood, generating direct and indirect costs for health systems. ^1–3

Understanding the factors associated with musculoskeletal pain in childhood and adolescence is essential, as this period represents a critical phase of physical, behavioral, and psychosocial development. Recent studies have highlighted that poor posture habits, sedentary behavior, prolonged use of electronic devices, and low levels of physical activity are often associated with the occurrence of spinal pain in schoolchildren, reinforcing the need for investigations that integrate multiple risk factors. ^4–6

Postural habits comprise the positions and movements adopted during activities of daily living, such as sitting, writing, using electronic devices, carrying school backpacks, and sleeping. Repeated exposure to poor posture during the school period can contribute to mechanical overload of the spine, favoring the onset of musculoskeletal pain. In this context, the Back Pain and Posture Evaluation Instrument (BackPEI), validated for Brazilian children and adolescents (BackPEI-CA), has been widely used to investigate the presence of back pain and its associated factors, including postural, behavioral, and demographic aspects. ^7–9

Despite the growing number of studies analyzing factors associated with musculoskeletal pain in children and adolescents, most investigations use traditional analytical approaches, focused on the isolated assessment of sociodemographic, behavioral, or postural variables. ^4,8 In contrast, more recent methodological approaches, such as network analysis, have been proposed to better capture the complex interrelationships among multiple factors. ^10,11 Additionally, studies in this field are commonly conducted and reported in accordance with established methodological guidelines. ¹² In this context, there are still a few studies that explore the simultaneous interaction between multiple individual, behavioral, and contextual factors, which may limit the understanding of the complexity involved in the development of musculoskeletal pain in this population. ^13–15

Network analysis has emerged as a promising statistical approach in the field of health, as it allows for the investigation of interrelationships between variables in an integrated manner, identifying direct and indirect connections between risk factors and clinical outcomes. Although still under-explored in pediatric epidemiological studies, this approach can contribute to a more comprehensive understanding of the patterns of association between musculoskeletal pain, postural habits, and individual characteristics in children and adolescents. ^10,11

Therefore, the present study aimed to analyze the relationship between musculoskeletal pain in the spine and individual, behavioral, and contextual factors in children and adolescents.

METHOD

This cross-sectional, observational, and exploratory study was conducted with children and adolescents enrolled in public and private schools in the city of Belém, Pará, Brazil, with the aim of describing the occurrence of musculoskeletal pain in the spine and exploring associations between individual, behavioral, and contextual factors in a pediatric population. The study was approved by the Research Ethics Committee of the Federal University of Pará (CAAE: 23163519.6.0000.0018), and all participants and their legal guardians were informed about the objectives and procedures of the research, with anonymity and confidentiality of information guaranteed, in accordance with the ethical principles of the Declaration of Helsinki. The reporting of this study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. ¹²

The study population consisted of children and adolescents of both sexes, aged between 10 and 16 years, who were regularly enrolled in elementary and high school. Participants were recruited from public and private schools that were invited to participate in the study. A total of 20 public schools were invited, of which five agreed to participate, and five private schools were invited, of which three agreed to participate. Children and adolescents who presented the Free and Informed Consent Form signed by their legal guardians, as well as the Assent Form, when applicable, were included, regardless of the presence of musculoskeletal pain. Participants with a difference in lower limb length greater than or equal to 1.5 cm, assessed using the apparent discrepancy test, measuring the distance between the umbilical scar and the medial malleolus, were excluded. Those with a history of orthopedic, neurological, neuromuscular, or cardiorespiratory diseases, previous orthopedic surgery, or developmental disorders that could interfere with the evaluation were also excluded.

Due to the exploratory nature of the study and the analytical approach based on network analysis, all students who met the eligibility criteria and agreed to participate during the data collection period were included. The final sample consisted of 189 participants.

After authorization from the Pará State Department of Education, the project was presented to the principals of the participating schools. In private schools, educational lectures on posture and back pain were held, followed by the delivery of the Free and Informed Consent Form to legal guardians. Data collection was carried out on the premises of the schools themselves, in a reserved space, by a team composed of physical therapists and previously trained physical therapy students, after the return of the duly signed consent form.

Participants completed an assessment form containing sociodemographic and clinical information, including gender, age, manual dominance, and physical activity. Family history of musculoskeletal pain was assessed through a self-reported dichotomous question (yes/no), based on the participant's report of similar pain in family members. This information was collected using an electronic form (Google Forms) to standardize records and reduce transcription errors. Body mass was measured with a digital scale, and height was measured using a tape measure fixed to the wall, with the participant barefoot and in an upright position. Body mass index was calculated as the ratio of body mass in kilograms to height in square meters.

Musculoskeletal pain and postural habits were assessed using the BackPEI-CA, consisting of 30 multiple-choice questions. Questions 1–20 assess postural and behavioral risk factors, including sitting posture during school activities, posture when using electronic devices (cell phones, tablets, and computers), posture when picking up objects from the floor, sleeping position, and the method of carrying school backpacks, while questions 21–30 investigate the presence, frequency, and intensity of back pain. The frequency of low back and neck pain was assessed using specific items of the instrument that capture the presence and recurrence of symptoms according to predefined response categories. Pain intensity was measured using the Numeric Rating Scale (NRS), ranging from 0 (no pain) to 10 (worst possible pain). Postural habits were classified according to the predefined categories of the instrument, which include illustrated options representing different body positions during daily activities. Participants were instructed to select the option that best represented their usual posture. For analytical purposes, these responses were categorized as adequate or inadequate according to the criteria established by the instrument. The instrument also assesses the impact of pain on school attendance and participation in recreational activities, using gender-specific versions, as recommended by the authors of the questionnaire.

Initially, a descriptive analysis of the data was performed, presenting means, standard deviations (SDs), medians, and absolute and relative frequencies, according to the nature of the variables. Categorical variables were presented as absolute and relative frequencies, whereas continuous variables were summarized using means and SDs. The main outcomes of the study were the presence of low back pain and neck pain, assessed using the BackPEI-CA. Independent variables included sociodemographic characteristics (age, gender, and type of school), behavioral factors (physical activity in different contexts), and postural habits related to daily activities (e.g., sitting posture at school, posture when picking up objects, and sleeping position) and the use of electronic devices (e.g., sitting and standing posture when using cell phones, tablets, and computers). To explore the associations between individual and behavioral factors and the presence of musculoskeletal pain in the spine, network analysis was applied. The EBICglasso estimator was used, which combines LASSO (Least Absolute Shrinkage and Selection Operator) graphical regularization with the Extended Bayesian Information Criterion, allowing the identification of a parsimonious network, maintaining only the most relevant associations between variables. A penalty parameter of 0.25 was adopted for LASSO regularization. The network visualization was generated using the spring layout algorithm, in which the proximity between nodes represents the strength of the associations. Blue edges indicate positive associations, while red edges indicate negative associations, with the thickness of the lines proportional to the magnitude of these associations. The relative importance of each variable in the network was assessed using the metrics of betweenness, closeness, strength, and expected influence. All analyses were performed using JASP software, version 0.18.3.

RESULT

A total of 189 students aged 10–16 years from public and private schools were included in the study. Schools were invited to participate, and a total of five public and three private schools agreed to participate. Participants were recruited according to predefined eligibility criteria, and those who did not meet the inclusion criteria or met exclusion criteria were not included in the final sample. Of the total sample, 76.7% were from public schools. Of the total sample, 48.6% were female, with a mean age of 11.5 years (SD=1.6). The sociodemographic and clinical characteristics of the participants are presented in Table 1.

Regarding musculoskeletal pain in the spine, a high prevalence of both low back and neck pain was observed among participants. Pain intensity was moderate for both regions, as assessed by the Numeric Rating Scale (Table 1).

Regarding postural and behavioral habits, a high prevalence of inadequate postures was observed across several daily activities, particularly during sitting and object-handling tasks. Sleep patterns were generally within recommended ranges, with the lateral decubitus position being the most frequently reported (Tables 2 and 3). Regarding the use of electronic devices, a considerable proportion of participants reported prolonged use, particularly of mobile phones, while computer use was less frequent (Table 2).

Network analysis revealed associations between individual and behavioral factors and the presence of musculoskeletal pain in the spine (Figure 1). Low back pain was negatively correlated with family history of pain (r=-0.14) and positively correlated with female gender (r=0.19) and the presence of neck pain (r=0.12). The position when sitting to use a cell phone or tablet showed a negative correlation with neck pain (r=-0.19). In addition, a negative correlation was observed between gender and physical activity outside school.

The centrality metrics indicated that the variables age (betweenness=1420) and gender (betweenness=1278) had the highest intermediation values in the network, suggesting greater influence on the flow of connections between the other variables. The gender variable also had the highest values for closeness (closeness=1301) and strength (strength=1450). Regarding expected influence, physical activity at school had a negative value (expected influence=-1764), as did the position when sitting to use a cell phone or tablet (expected influence=-1144). The centrality and expected influence metrics are shown in Table 4.

DISCUSSION

This study analyzed the relationship between musculoskeletal pain in the spine and individual, behavioral, and contextual factors in children and adolescents using an exploratory approach based on network analysis. The findings showed a high prevalence of low back and neck pain, as well as associations between musculoskeletal pain, gender, age, physical activity, and postural habits, reinforcing the multifactorial nature of this outcome in the pediatric population.

The prevalences of low back pain (62.6%) and neck pain (65.4%) observed are consistent with national and international studies that point to musculoskeletal pain as frequent during childhood and adolescence, with the potential to persist over time. ^13–16 These findings reinforce the relevance of musculoskeletal pain as a public health problem already at school age. Several factors may help explain these estimates. First, the age range evaluated (10–16 years) corresponds to a developmental stage in which musculoskeletal symptoms tend to become more frequent due to rapid growth, behavioral changes, and increased exposure to sedentary activities. ^13–18 Second, the BackPEI-CA is a validated self-report instrument that captures both current and recurrent episodes of spinal pain, which may contribute to higher prevalence estimates compared with studies using stricter definitions of pain. ⁷ In addition, contextual factors related to lifestyle, such as prolonged use of electronic devices and the high prevalence of inadequate postural habits observed in the present sample, may also contribute to the occurrence of musculoskeletal pain in this population. ^19–24

Gender was central to the network and positively associated with low back pain, consistent with evidence indicating a higher prevalence of musculoskeletal pain among girls, especially during adolescence. ^13–16 Age also showed high centrality, corroborating studies that identify adolescence as a critical period for the emergence and consolidation of musculoskeletal symptoms, possibly due to bodily and behavioral changes and increased time spent in sedentary activities. ^13–16

Physical activity, particularly in the school environment, had a negative influence on the network, suggesting an association with less impact from musculoskeletal pain. Although network analysis does not allow causal inferences, this finding is in line with international guidelines and systematic reviews that indicate regular physical activity as a potentially protective factor for the musculoskeletal health of children and adolescents. ¹⁸

A high prevalence of poor posture habits was observed during school activities and when using electronic devices. The posture adopted when sitting to use a cell phone or tablet was associated with neck pain, suggesting that poor posture behaviors may be related to neck pain. However, the literature presents inconsistent results regarding the direct association between the use of electronic devices and musculoskeletal pain, indicating that factors such as sleep quality, physical inactivity, and biopsychosocial aspects may play a more relevant role. ^19–24 In addition, factors such as sleep patterns and ergonomic conditions may also influence musculoskeletal health in children and adolescents. ^25–27 Other ergonomic factors commonly discussed in the literature include the transport of school backpacks, which has been investigated as a potential contributor to back pain in schoolchildren, although current evidence remains inconclusive. ^28,29

In the present study, a considerable portion of participants reported sleep duration close to the recommended amount. Recent evidence points to a bidirectional relationship between sleep disorders and chronic musculoskeletal pain, indicating that sleep problems may increase the risk of pain in both the short and long term. ^25,26 In addition, inadequate ergonomic conditions in the school environment, such as furniture that is not adapted to anthropometric characteristics, can contribute to musculoskeletal overload. ²⁷

The use of network analysis represents a methodological advance, as it allows the integrated exploration of the interrelationships between multiple factors associated with musculoskeletal pain, identifying central variables that might not be evident in traditional analytical approaches. However, some limitations should be considered when interpreting the results. First, the cross-sectional design does not allow causal inferences. Second, the use of self-reported measures may introduce recall bias. In addition, the findings of this study should be interpreted considering some limitations. Although invited schools agreed to participate to varying extents, the sample was obtained through a non-probabilistic strategy, which may limit its representativeness, particularly regarding socioeconomic diversity. In addition, the restriction to a single Brazilian city may affect the generalizability of the findings. Despite these limitations, the study included students from both public and private schools, providing a heterogeneous sample of schoolchildren. Future multicenter studies with probabilistic sampling and longitudinal designs are recommended to confirm and expand these findings in broader populations.

In conclusion, this study showed a high prevalence of musculoskeletal pain in the spine in children and adolescents, as well as associations with individual, behavioral, and contextual factors. The network analysis highlighted gender, age, physical activity, and postural habits as central variables in the observed interrelationships. These findings reinforce the multifactorial nature of musculoskeletal pain in the pediatric population and the importance of integrated approaches aimed at health promotion and early prevention.

Funding Statement

Funding This study received financial support from the Coordination for the Improvement of Higher Education Personnel (CAPES), Brazil, grant number 88887.826254/2023-00.

Data availability statement

The dataset that supported the findings of this study is available from the corresponding author upon reasonable request.