Genetic and environmental influences on non-specific low back pain in children: a twin study

Prevalence of spine pain among Tunisian children and adolescents and related factors

BACKGROUND

The prevalence of back and neck pain is common in children and adolescents, and in some series the numbers are alarming. Various risk factors have been identified, although some are controversial.

OBJECTIVE

To determine the prevalence of neck and back pain in children and adolescents and to investigate the potential association with various risk factors identified in the literature.

METHODS

We established a questionnaire targeting parents of children and adolescents aged between 6 and 18 years old in Tunisia. The recruitment of participants was done online using the Google Forms application. The questionnaire was divided into 2 parts: Part one collected the sociodemographics characteristics of the participants : age, gender, body mass index (BMI), exposure to passive smoking, the practice of a physical activity, puberty status and age at puberty if applicable, type and weight of the schoolbag, mean daily time spent on electronic devices, type of school the child attends (private/public), mode of transport from home to school, parental history of neck and/or back pain (mid or low back pain (LBP)), posture of the sitting position of the child, and finally whether the child reports neck/ back pain. The second part was aimed at parents whose child reported neck and/or back pain. We asked about the weekly frequency of neck/back pain, school absenteeism due to neck/back pain, whether it prevented the child from practicing physical activity and, finally, whether the child had ever seen a doctor/chiropractor/physiotherapist for their neck/back pain.

RESULTS

Eighty-eight children (45 females, 43 males) were enrolled. Mean age was 11.9 ± 3.8 years [6-18]. Mean BMI was 18.8 ± 4.2 [15.8-35.5]. Thirty-four (38.6%) were pubescent. Twenty-five (28.4%) children were exposed to passive smoking. Parental history of spine pain was found in 58% of cases. A poor sitting position was noted in n = 49 (55.7%). Mean daily screen time was 88.3 ± 75.56 min [0-360]. Prevalence of spine pain was 44% (n = 39) distributed as follows: neck pain (n = 21, 23.8%), mid back pain (n = 15, 17%), LBP (n = 26, 29.5%), neck, mid back and low back pain (n = 4, 4.5%) Professional help seeking for spine pain in children was reported by 15 participants (25.3%). Among them, 20.3% visited a physician and 5% consulted a chiropractor or physiotherapist. A significant correlation was found between spine pain and age (p = 0.006) and BMI (p = 0.006). A significant association was found between LBP and exposure to passive smoking, puberty status, type of school bag and poor posture. A positive parental history of spine pain was significantly associated with the presence of spine pain in their children with p = 0.053 (neck pain), p = 0.013 (back pain) and p < 0.00 (LBP) respectively. A significant association was found between the presence of spine pain and school absenteeism, participation in sports, consultation with a doctor or physiotherapist/chiropractor (p < 0.0001 respectively).

CONCLUSION

The prevalence of spinal pain was frequent in our series. A positive parental history of spinal pain, a bad posture while sitting, passive smoking, use of backpack, higher age and higher BMI were potential associated factors.

Non-Specific Low Back Pain: An Inductive Exploratory Analysis through Factor Analysis and Deep Learning for Better Clustering

Non-specific low back pain (NSLBP) is a significant and pervasive public health issue in contemporary society. Despite the widespread prevalence of NSLBP, our understanding of its underlying causes, as well as our capacity to provide effective treatments, remains limited due to the high diversity in the population that does not respond to generic treatments. Clustering the NSLBP population based on shared characteristics offers a potential solution for developing personalized interventions. However, the complexity of NSLBP and the reliance on subjective categorical data in previous attempts present challenges in achieving reliable and clinically meaningful clusters. This study aims to explore the influence and importance of objective, continuous variables related to NSLBP and how to use these variables effectively to facilitate the clustering of NSLBP patients into meaningful subgroups. Data were acquired from 46 subjects who performed six simple movement tasks (back extension, back flexion, lateral trunk flexion right, lateral trunk flexion left, trunk rotation right, and trunk rotation left) at two different speeds (maximum and preferred). High-density electromyography (HD EMG) data from the lower back region were acquired, jointly with motion capture data, using passive reflective markers on the subject's body and clusters of markers on the subject's spine. An exploratory analysis was conducted using a deep neural network and factor analysis. Based on selected variables, various models were trained to classify individuals as healthy or having NSLBP in order to assess the importance of different variables. The models were trained using different subsets of data, including all variables, only anthropometric data (e.g., age, BMI, height, weight, and sex), only biomechanical data (e.g., shoulder and lower back movement), only neuromuscular data (e.g., HD EMG activity), or only balance-related data. The models achieved high accuracy in categorizing individuals as healthy or having NSLBP (full model: 93.30%, anthropometric model: 94.40%, biomechanical model: 84.47%, neuromuscular model: 88.07%, and balance model: 74.73%). Factor analysis revealed that individuals with NSLBP exhibited different movement patterns to healthy individuals, characterized by slower and more rigid movements. Anthropometric variables (age, sex, and BMI) were significantly correlated with NSLBP components. In conclusion, different data types, such as body measurements, movement patterns, and neuromuscular activity, can provide valuable information for identifying individuals with NSLBP. To gain a comprehensive understanding of NSLBP, it is crucial to investigate the main domains influencing its prognosis as a cohesive unit rather than studying them in isolation. Simplifying the conditions for acquiring dynamic data is recommended to reduce data complexity, and using back flexion and trunk rotation as effective options should be further explored.

Associations Between Adolescent Pain and Psychopathology in the Adolescent Brain Cognitive Development (ABCD) Study

Pain and psychopathology co-occur in adolescence, but the directionality and etiology of these associations are unclear. Using the pain questionnaire and the Child Behavior Checklist from the Adolescent Brain Cognitive Development study (n = 10,414 children [770 twin pairs] aged 12-13), we estimated longitudinal, co-twin control, and twin models to evaluate the nature of these associations. In two-wave cross-lag panel models, there were small cross-lag effects that suggested bidirectional associations. However, the co-twin control models suggested that most associations were familial. Pain at age 12 and 13 was mostly environmental (A = 0-12%, C = 15-30%, E = 70-73%) and the twin models suggested that associations with psychopathology were primarily due to shared environmental correlations. The exception was externalizing, which had a phenotypic prospective effect on pain, a significant within-family component, and a non-shared environmental correlation at age 12. Environmental risk factors may play a role in pain-psychopathology co-occurrence. Future studies can examine risk factors such as stressful life events.

Back Pain without Disease or Substantial Injury in Children and Adolescents: A Twin Family Study Investigating Genetic Influence and Associations

This twin family study first aimed to investigate the evidence for genetic factors predicting the risk of lifetime prevalence of non-specific low back pain of at least three months duration (LBP (life)) and one-month current prevalence of thoracolumbar back pain (TLBP (current)) using a study of children, adolescents, and their first-degree relatives. Secondly, the study aimed to identify associations between pain in the back with pain in other regions and also with other conditions of interest. Randomly selected families (n = 2479) with child or adolescent twin pairs and their biological parents and first siblings were approached by Twins Research Australia. There were 651 complete twin pairs aged 6-20 years (response 26%). Casewise concordance, correlation, and odds ratios were compared for monozygous (MZ) and dizygous (DZ) pairs to enable inference about the potential existence of genetic vulnerability. Multivariable random effects logistic regression was used to estimate associations between LBP (life) or TLBP (current) as an outcome with the potentially relevant condition as predictors. The MZ pairs were more similar than the DZ pairs for each of the back pain conditions (all p values < 0.02). Both back pain conditions were associated with pain in multiple sites and with primary pain and other conditions using the combined twin and sibling sample (n = 1382). Data were consistent with the existence of genetic influences on the pain measures under the equal environments assumption of the classic twin model and associations with both categories of back pain were consistent with primary pain conditions and syndromes of childhood and adolescence which has research and clinical implications.

Back Problems: Pros and Cons of Core Strengthening Exercises as a Part of Athlete Training

While competitive training is usually associated with the prevalence of back pain and injuries in athletes, little attention is being paid to the positive effects of sport-specific exercises on core musculature in the prevention of back problems. This scoping review aims (i) to map the literature that addresses the effects on reduction of back problems following athlete training with differing demands on the core musculature and (ii) to identify gaps in the existing literature and propose future research on this topic. The main literature search was conducted on the MEDLINE, PubMed, Web of Science, Scopus, and Cochrane Library databases and was completed on Elsevier, SpringerLink, and Google Scholar. A total of 21 research articles met the inclusion criteria. The findings of 17 studies identified that core strengthening and core stabilization exercises, alone or in combination with athlete training, contribute to the reduction of back pain in athletes, whereas only four studies revealed no significant association of core muscle strength and/or endurance with back problems. Nevertheless, more research is warranted to elucidate the pros and cons of purely sport-specific training with differing demands on the core musculature on back health in athletes. This could help us to design prevention strategies specifically tailored to individual athletes.

Familial and Genetic Influences on the Common Pediatric Primary Pain Disorders: A Twin Family Study

The primary pain disorders of childhood are highly prevalent but have infrequently been studied collectively. Genetic influences have been suggested to be causally implicated. Surveys were sent to 3909 Australian twin families, assessing the lifetime prevalence of growing pains, migraine, headache, recurrent abdominal pain, low back pain, and persistent pain (not otherwise specified) in pediatric twins and their immediate family members. Comparisons between monozygous (MZ) and dizygous (DZ) twin pair correlations, concordances and odds ratios were performed to assess the contribution of additive genetic influences. Random-effects logistic regression modelling was used to evaluate relationships between twin individuals and their co-twins, mothers, fathers and oldest siblings with the subject conditions. Twin analyses of responses from 1016 families revealed significant influence of additive genetic effects on the presence of growing pains, migraine, and recurrent abdominal pain. The analyses for headache, low back pain, and persistent pain overall did not conclusively demonstrate that genetic influences were implicated more than shared environmental factors. Regression analyses demonstrated varying levels of significance in relationships between family members and twin individuals for the tested conditions, with strongest support for genetic influences in growing pains and migraine. These data, together with previously published association analyses, suggest common causal influences including genes.

Family history of pain and risk of musculoskeletal pain in children and adolescents: a systematic review and meta-analysis

Emerging evidence suggests that musculoskeletal (MSK) pain should be viewed from a biopsychosocial perspective and consider the influence of family factors. We conducted a review with meta-analysis to provide summary estimates of effect of family history of pain on childhood MSK pain and explore whether specific family pain factors influence the strength of the association (PROSPERO CRD42018090130). Included studies reported associations between family history of pain and nonspecific MSK pain in children (age <19 years). The outcome of interest was MSK pain in children. We assessed the methodological quality using a modified version of the Quality in Prognosis Studies instrument and quality of evidence for the main analyses using the GRADE criteria. After screening of 7281 titles, 6 longitudinal and 23 cross-sectional studies were included. Moderate quality evidence from 5 longitudinal studies (n = 42,131) showed that children with a family history of MSK pain had 58% increased odds of experiencing MSK pain themselves (odds ratio [OR] 1.58, 95% confidence interval 1.20-2.09). Moderate quality evidence from 18 cross-sectional studies (n = 17,274) supported this finding (OR 2.02, 95% 1.69-2.42). Subgroup analyses showed that the relationship was robust regardless of whether a child's mother, father, or sibling experienced pain. Odds were higher when both parents reported pain compared with one ([mother OR = 1.61; father OR = 1.59]; both parents OR = 2.0). Our findings show moderate quality evidence that children with a family history of pain are at higher risk of experiencing MSK pain. Understanding the mechanism by which this occurs would inform prevention and treatment efforts.

Baseline musculoskeletal pain and impaired sleep related to school pressure influence the development of musculoskeletal pain in N = 107 adolescents in a 5-year longitudinal study

PURPOSE

This longitudinal study followed 10- to 13-year-old adolescents for 5 years to investigate the effects of juvenile musculoskeletal (MSK) pain and psychosocial risk factors on future pain. We further predicted that increased MSK pain at follow-up would be positively related to current school pressure at follow-up and negatively related to current sleep quality. Sleep quality was tested as a potential mediator of the link between school pressure and MSK pain at follow-up after controlling for baseline MSK pain.

METHODS

The baseline sample comprised 189 adolescents, and 5-year follow-up resulted in 107 15- to 18-year-old adolescents who had completed mandatory education. Adolescents responded to an online questionnaire about psychosocial stressors, MSK pain, school achievement and leisure activities. A longitudinal hierarchic linear regression including all significant baseline predictors was run to assess their impact on MSK pain 5 years later. Mediation analysis was used to investigate sleep quality as a potential mediator of the relationship between school pressure and MSK pain at follow-up.

RESULTS

Baseline MSK pain predicted MSK pain over a time lag of 5 years (ß = .26, p = .02). The relationship between follow-up school pressure and current MSK pain was mediated by sleep quality at follow-up (B = .17, SE_B = .07, 95% CI .06-.34) when baseline MSK pain was controlled.

CONCLUSIONS

Juvenile MSK pain predicts MSK pain in adolescence. A psychosocial mediation model including school pressure and sleep impairments has the potential to explain MSK pain mechanisms in adolescents. These slides can be retrieved under Electronic Supplementary Material.

Back pain and its risk factors in Brazilian adolescents: a longitudinal study

Owing to the lack of longitudinal studies in Latin American countries, we aimed to evaluate back pain and its risk factors in a 3-year longitudinal study of Brazilian adolescents. We analysed data of 525 adolescents (aged 11-16 years) attending primary school (fifth to eighth grade) in Brazil. The students were administered the self-reported Back Pain and Body Posture Evaluation Instrument (BackPEI) questionnaire in 2011 and at a follow-up evaluation that was conducted 3 years later (2014). Back pain was the outcome variable; the exposure variables included exercise, behavioural, hereditary and postural factors. Generalized estimating equations were used to perform a Poisson regression model with robust variance to evaluate the risk factors for back pain. The prevalence of back pain at baseline was 56% (n = 294); this increased significantly at the 3-year follow-up evaluation to 65.9% (n = 346). The frequency of experiencing back pain also significantly increased after 3 years in both boys (p = 0.002) and girls (p = 0.001). The prevalence of back pain increased significantly in adolescents up to the age of 13 years, stabilized in those aged 14 years and older and was higher among girls. A family history of back pain (in the parents), watching television for lengthy periods and carrying a backpack asymmetrically were predictors for back pain.

Sports participation and low back pain in schoolchildren

BACKGROUND

Low back pain (LBP) is one of the biggest health problems worldwide.

OBJECTIVES

The purpose of this study was to investigate the association between sports participation (duration and type) and LBP related outcomes in childhood.

METHODS

This cross-sectional study involved 5th and 6th grade primary school students. The final sample included 2,032 children aged 10-12 years old. Children completed a questionnaire about the prevalence of LBP and some LBP-related outcomes. In addition, the participants were surveyed about the type of sport they did and the duration.

RESULTS

There appears to be no relation between sports participation and severity of LBP-related outcomes studied, independently of their duration. Participating in football ⩾ 4 hours per week was associated with a decrease of six LBP-related outcomes (OR ranging from 0.54 to 0.66). Basketball participation does not seem to affect the development of back problems amongst children.

CONCLUSIONS

It can be suggested with caution that doing sport is not dangerous for LBP problems in children aged 10-12 years old. Nevertheless, this suggestion should be tested with further longitudinal and intervention studies to confirm the results.

Epidemiology of spinal pain in children: a study within the Danish National Birth Cohort

This study aims to describe the prevalence of spinal pain among Danish children, explore the differential nature of spinal pain, and investigate socio-demographic factors predisposing spinal pain. A descriptive study of 46,726 11-14-year-olds participating in the Danish National Birth Cohort was conducted. Self-reported spinal pain (neck, middle back, and low back pain) was registered and classified according to severity. Socioeconomic data on children and their parents were identified in Statistics Denmark registers. Associations between socio-demographic factors and aspects of spinal pain were estimated using multinomial logistic regression models. To account for sample selection, inverse probability weighting (IPW) was applied. Almost 10% boys and 14% girls reported severe spinal pain, whereas around 30% of all children reported moderate pain. Effect estimates indicated the risk to increase with increasing age. Further, children without biological full siblings, not living with both of their parents, or children living in less-educated or lower-income families were more likely to experience spinal pain. The study conclusions were essentially unaffected by IPW.Conclusion: A considerable number of children suffer from spinal pain, and it is more common among children in more disadvantaged families. Etiology of spinal pain needs to be explored further with the aim of informing efficient and targeted prevention. What is Known: • Childhood spinal pain may cause marked discomfort and impairment in children's everyday life, and is suggested as important predictor of later-in-life spinal pain. • Methodological heterogeneity in previous studies and complexity of measuring pain make inferences at a broader level inadequate. What is New: • Prevalence of severe spinal pain in 11-14-year-olds was estimated to almost 10% for boys and 14% for girls, and children in more disadvantaged families were more likely to experience spinal pain. • The results seemed unaffected by sample selection.

Contributions of birthweight, annualised weight gain and BMI to back pain in adults: a population-based co-twin control study of 2754 Australian twins

PURPOSE

To investigate associations between anthropometric measures (birthweight, weight gain and current BMI) and back pain; and to determine whether these associations differ between those born with low or full birthweight.

METHODS

The cross-sectional associations between the lifetime prevalence of back pain and anthropometric measures (birthweight, weight gain and current BMI) among 2754 adult twins were investigated in three stages: total sample; within-pair case-control for monozygotic and dizygotic twins together; and within-pair case-control analysis separated by dizygotic and monozygotic. Results were expressed as odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Birthweight was not associated with back pain (OR 0.99; 95% CI 0.99-1.00), but a weak association was found between weight gain (OR 1.01; CI 1.00-1.01) or current BMI (OR 1.02; 95% CI 1.00-1.05) and back pain in the total sample analysis. These associations did not remain significant after adjusting for genetics. The associations did not differ between those whose were born with low or full birthweight.

CONCLUSION

Birthweight was not associated with prevalence of back pain in adulthood. Weight gain and current BMI were weakly associated with back pain prevalence in the total sample analysis but did not differ between those born with low or full birthweight. However, the small-magnitude association only just achieved significance and appeared to be confounded by genetics and the early shared environment. Our results suggest that a direct link between these predictors and back pain in adults is unlikely. These slides can be retrieved under Electronic Supplementary Material.

Low back pain

Low back pain affects individuals of all ages and is a leading contributor to disease burden worldwide. Despite advancements in assessment and treatment methods, the management of low back pain remains a challenge for researchers and clinicians alike. One reason for the limited success in identifying effective treatments is the large variation in the manifestations, possible causes, precipitating and maintaining factors, course, prognosis and consequences in terms of activity interference and quality of life. However, despite these challenges, steady progress has been achieved in the understanding of back pain, and important steps in the understanding of the psychological and social risk factors, genetics and brain mechanisms of low back pain have been made. These new findings have given impetus to the development of new diagnostic procedures, evidence-based screening methods and more targeted interventions, which underscore the need for a multidisciplinary approach to the management of low back pain that integrates biological, psychological and social aspects.

Relationship between pubertal timing and chronic nonspecific pain in adolescent girls: the Young-HUNT3 study (2006-2008)

The aim of this study was to examine a possible relationship between early puberty and chronic nonspecific pain in 13- to 18-year-old girls. All adolescents in Nord-Trøndelag County, Norway, were invited to participate in the Young-HUNT3 study (2006-2008). Of the invited girls, 81% answered the questionnaire and of these 3982 were 13 to 18 years of age. Menarche and perceived physical maturation were used as exposure measures. Early menarche was defined as <12 years, normal menarche as ≥12 and <14 years, and late menarche as ≥14 years. Perceived physical maturation was divided into maturing earlier, the same or later than others of their own age. The main outcome measure was chronic nonspecific pain, defined as pain in at least one location not related to any known disease or injury, for at least once a week during the last 3 months. The median age at menarche was 13.2 years. Chronic nonspecific pain was more prevalent among girls with early menarche (68%, 95% CI: 64%-72%) compared to girls with either normal (55%, 95% CI: 53%-57%), late (50%, 95% CI: 46%-54%), or no menarche (35%, 95% CI: 29%-40%). The association persisted after adjusting for age, body mass index, socioeconomic factors, and anxiety and depression. A similar association was found between girls that perceived themselves as earlier physically matured than their peers and chronic nonspecific pain. Headache/migraine was the most common type of chronic nonspecific pain regardless of menarcheal age. In all reported locations, pain was more prevalent in the group with early menarche compared to normal or late menarche.

Genetic and Environmental Contributions to Sleep Quality and Low Back Pain: A Population-Based Twin Study

OBJECTIVE

The aim of the study was to estimate the extent to which the co-occurrence of poor sleep quality and low back pain is due to the same genetic and/or environmental risk factors or due to a causal association.

METHODS

Cross-sectional data on sleep quality (Pittsburgh Sleep Quality index) and low back pain were collected in a population-based sample of adult twins (N = 2134) registered with the Murcia Twin Registry. Bivariate analysis and structural equation modeling were used.

RESULTS

The phenotypic correlation between sleep quality and low back pain was 0.23 (95% confidence interval [CI] = 0.17-0.28). The best-fitting bivariate model included additive genetic and unique environmental factors. Genetic factors accounted for 26% (95% CI = 10-40) and 34% (95% CI = 25-43) of the variability of low back pain and sleep quality, respectively. The correlation between the genetic factors underlying each trait was rG of 0.33 (95% CI = 0.03-0.66), and this overlap of genetic factors explained 42.5% of the phenotypic correlation. On the other hand, nonshared environmental factors of each variable were only fairly correlated rE of 0.19 (95% CI = 0.06-0.31), although this overlap explained 57.5% of the phenotypic correlation. In addition, twins in monozygotic pairs with poorer sleep quality presented more often with low back pain than their co-twins (ρ^ = 0.25, p < .0001).

CONCLUSIONS

The data are compatible with a causal effect of sleep quality on low back pain (or the reverse effect), because the correlations between the genetic and unique environmental factors for each trait were significant and there was a significant correlation between the monozygotic twins' difference scores. Apart from environmental factors that affect both characteristics, there are many individual-specific events that influence low back pain but differ from those influencing sleep quality.

Genetic and environmental influences to low back pain and symptoms of depression and anxiety: A population-based twin study

BACKGROUND

People suffering from chronic pain are more likely to experience symptoms of depression and anxiety. However, the mechanisms underlying this relationship remain largely unknown. In light of the moderate to large effects of genetic factors on chronic pain and depression and anxiety, we aimed to estimate the relative contribution of genetic and environmental factors to the relationship between these traits.

METHODS

Using data from 2139 participants in the Murcia Twin Registry, we employed a bivariate analysis and structural equation modeling to estimate the relative influences of genetics and the environment on the covariation between low back pain and symptoms of depression and anxiety.

RESULTS

We have obtained heritability estimates of 0.26 (95% Confidence Interval (CI) 0.11, 0.41) for chronic low back pain and 0.45 (95% CI 0.29, 0.50) for symptoms of depression and anxiety. The phenotypic, genetic, and unique environment correlations in the bivariate analytical model were, respectively, r_ph=0.26 (95% CI 0.19, 0.33); r_G=0.47 (95% CI 0.42, 0.70); r_E=0.14 (95% CI -0.04, 0.25). The percentage of covariance between low back pain and symptoms of depression and anxiety attributable to additive genetic factors was 63.6%, and to unique environment 36.4%.

CONCLUSIONS

Our findings confirm the relationship between low back pain and symptoms of depression and anxiety in a non-clinical sample. Shared genetic factors affect significantly the covariation between these conditions, supporting the role of common biological and physiological pathways.

A scoping review on the study of siblings in pediatric pain

Background: Sibling relationships are longstanding across an individual’s life and are influential in children’s development. The study of siblings in pediatric pain is, although in early stages, a growing field.

Aims: This scoping review sought to summarize and map the type of research available examining siblings and pediatric pain to identify gaps and directions for future research.

Methods: Studies were identified based on a search of PubMed, CINAHL, PsycInfo, Embase, and Web of Science (up to November 2016). We extracted data about study methods, the sample, outcome assessment, and the influence/relationships investigated.

Results: Thirty-five studies were included. Most studies used quantitative methods (n = 28), and participants typically included children (i.e., aged 6–12; n = 24) and adolescents (i.e., aged 13–18; n = 18). The majority of studies examined siblings in the context of chronic and disease-related pain (n = 30). Though quantitative studies primarily focused on the genetic influence of pain conditions (n = 18), qualitative and mixed-methods studies typically focused on exploring the impact of siblings with and without pain on one another (n = 2) and the impact of pain on the broader dyadic relationship/functioning (n = 4).

Conclusions: Sibling research in pediatric pain has been primarily focused on the biological/physical components of pain, using quantitative approaches. Conducting more studies using qualitative or mixed-methods designs, incorporating multiple assessment measures (e.g., observational, self-report) and multiple perspectives (e.g., siblings, health professionals), may provide an opportunity to gain richer and more comprehensive information regarding the experience of siblings.

Understanding Adolescent Low Back Pain From a Multidimensional Perspective: Implications for Management

Synopsis Low back pain (LBP) is the leading cause of disability worldwide. It often begins in adolescence, setting a course for later in life. We have tracked the course of LBP in the Raine Study cohort from the age of 14 years into early adulthood. Our work has found that LBP is already prevalent in individuals at 14 years of age and increases throughout adolescence and into early adulthood. It is often comorbid with other musculoskeletal pain. For some adolescents, LBP has little impact; for others, its impact includes care seeking, taking medication, taking time off from school and work, as well as modifying physical and functional activity. Of concern is the increasing prevalence of LBP with impact across adolescence, reaching adult rates by 22 years of age. The predictors of disabling LBP in adolescence are multidimensional. They include female sex, negative back pain beliefs, poor mental health status, somatic complaints, involvement in sports, and altered stress responses. Genetics also plays a role. Ironically, the factors that we have historically thought to be important predictors of LBP, such as "poor" spinal posture, scoliosis, carrying school bags, joint hypermobility, and poor back muscle endurance, are not strong predictors. This challenges our clinical beliefs and highlights that adolescent LBP needs a flexible and targeted multidimensional approach to assessment and management. In most cases, we recommend a cognitive functional approach that challenges negative LBP beliefs, educates adolescents regarding factors associated with their LBP, restores functional capacity where it is impaired, and encourages healthy lifestyle habits. J Orthop Sports Phys Ther 2017;47(10):741-751. Epub 12 Sep 2017. doi:10.2519/jospt.2017.7376.

Does Familial Aggregation of Chronic Low Back Pain Affect Recovery?: A Population-Based Twin Study

STUDY DESIGN

Longitudinal twin-cohort study.

OBJECTIVE

To investigate the effect familial aggregation of chronic low back pain (LBP) has on the recovery from chronic LBP.

SUMMARY OF BACKGROUND DATA

LBP is a worldwide problem, with pain and disability often becoming chronic. Genetics and familial behaviors could significantly affect the recovery from chronic LBP but have not been extensively investigated.

METHODS

A total of 624 Spanish twins from the Murcia Twin Registry reported experiencing chronic LBP within the past 2 years during the 2009/11 data collection wave and were followed up in 2013. Familial aggregation of chronic LBP was determined by the co-twin experiencing chronic LBP within the past 2 years at baseline. Twins reporting LBP "within the past 4 weeks" at follow-up were considered to have not recovered.

RESULTS

There were 455 twins with available data on LBP at follow-up and available data on LBP from their co-twin at baseline. Twins with an affected co-twin at baseline were significantly more likely to have not recovered from chronic LBP at follow-up (odds ratio [OR] = 1.6, 95% confidence interval [CI]: 1.0-2.4, P = 0.046). This relationship was stronger for monozygotic twins (OR = 2.5, 95% CI: 1.3-4.8, P = 0.006) (n = 172) but disappeared when considering only dizygotic twins (OR = 1.1, 95% CI: 0.6-2.0, P = 0.668) (n = 283). Sibling-relative recurrence risk (λ s) was 1.2 for the total sample, 1.5 for monozygotic twins, and 1.1 for dizygotic twins.

CONCLUSION

Having a sibling with chronic LBP at baseline increased the likelihood of LBP at follow-up by 20%, with this likelihood increasing to 50% if the sibling was an identical twin. These results are novel and highlight the important influence genetics have on people's recovery from chronic LBP. Information regarding the presence of chronic LBP within a family is easy to obtain and has the potential to inform clinicians on which patients are less likely to recover when treatment implementation is not considered.

LEVEL OF EVIDENCE

3.

Multivariable modeling of factors associated with spinal pain in young adolescence

PURPOSE

To investigate the factors related to the 1-month period prevalence of low back pain (LBP), neck pain (NP) and thoracic spine pain (TSP) in young adolescents, thereby considering potential correlates from the physical, sociodemographic, lifestyle, psychosocial and comorbid pain domains.

METHODS

In this cross-sectional baseline study, 69 factors potentially associated with spinal pain were assessed among 842 healthy adolescents before pubertal peak growth. With consideration for possible sex differences in associations, multivariable analysis was used to simultaneously evaluate contributions of all variables collected in the five domains.

RESULTS

A significantly higher odds of LBP was shown for having high levels of psychosomatic complaints (odds ratio: 4.4; 95 % confidence interval: 1.6-11.9), a high lumbar lordotic apex, retroversed pelvis, introverted personality, and high levels of negative over positive affect. Associations with a higher prevalence and odds of NP were found for psychosomatic complaints (7.8; 2.5-23.9), TSP in the last month (4.9; 2.2-10.8), backward trunk lean, high levels of negative over positive affect and depressed mood. Having experienced LBP (2.7; 1.3-5.7) or NP (5.5; 2.6-11.8) in the preceding month was associated with a higher odds of TSP, as were low self-esteem, excessive physical activity, sedentarism and not achieving the Fit-norm.

CONCLUSIONS

Psychosomatic symptoms and pain comorbidities had the strongest association with 1-month period prevalence of spinal pain in young adolescents, followed by factors from the physical and psychosocial domains. The role that "physical factors" play in non-adult spinal pain may have been underestimated by previous studies.

Back Pain Prevalence and Its Associated Factors in Brazilian Athletes from Public High Schools: A Cross-Sectional Study

Most studies on the prevalence of back pain have evaluated it in developed countries (Human Development Index--HDI > 0.808), and their conclusions may not hold for developing countries. The aim of this study was to identify the prevalence of back pain in representative Brazilian athletes from public high schools. This cross-sectional study was performed during the state phase of the 2015 Jogos dos Institutos Federais (JIF), or Federal Institutes Games, in Brazil (HDI = 0.744), and it enrolled 251 athletes, 173 males and 78 females (14-20 years old). The dependent variable was back pain, and the independent variables were demographic, socioeconomic, psychosocial, hereditary, exercise-level, anthropometric, strength, behavioral, and postural factors. The prevalence ratio (PR) was calculated using multivariable analysis according to the Poisson regression model (α = 0.05). The prevalence of back pain in the three months prior to the study was 43.7% (n = 104), and 26% of the athletes reported feeling back pain only once. Multivariable analysis showed that back pain was associated with demographic (sex), psychosocial (loneliness and loss of sleep in the previous year), hereditary (ethnicity, parental back pain), strength (lumbar and hand forces), anthropometric (body mass index), behavioral (sleeping time per night, reading and studying in bed, smoking habits in the previous month), and postural (sitting posture while writing, while on a bench, and while using a computer) variables. Participants who recorded higher levels of lumbar and manual forces reported a lower prevalence of back pain (PR < 0.79), whereas feeling lonely in the previous year, obesity, and ethnicity exhibited the highest prevalence ratio (PR > 1.30). In conclusion, there is no association between exercise levels and back pain but there is an association between back pain and non-exercise related variables.

An exploration of familial associations of two movement pattern-derived subgroups of chronic disabling low back pain; a cross-sectional cohort study

BACKGROUND

Altered movement patterns with pain have been demonstrated in children, adolescents and adults with chronic disabling low back pain (CDLBP). A previously developed classification system has identified different subgroups including active extension and multidirectional patterns in patients with CDLBP. While familial associations have been identified for certain spinal postures in standing, it is unknown whether a familial relationship might exist between movement pattern-derived subgroups in families with CDLBP.

OBJECTIVES

This study explored whether familial associations in movement pattern-derived subgroups within and between members of families with CDLBP existed.

DESIGN

Cross-sectional cohort study.

METHOD

33 parents and 28 children with CDLBP were classified into two subgroups based on clinical analysis of video footage of postures and functional movements, combined with aggravating factors obtained from Oswestry Disability Questionnaire. Prevalence of subgroups within family members was determined, associations between parent and child's subgroup membership was evaluated using Fisher's exact test, and spearman's correlation coefficient was used to determine the strength of association between familial dyads.

RESULTS

The majority of parents were classified as active extenders, sons predominately multidirectional and daughters were evenly distributed between the two subgroups. No significant association was found when comparing subgroups in nine parent-child relationships.

CONCLUSIONS

The exploration of a small cohort of family dyads in this study demonstrated that children's movement pattern-derived subgroups could not be explained by their parents' subgroup membership. These results cannot be generalised to the CLBP population due to this study's small sample. Larger sample studies are needed to further elucidate this issue.

Risk factors for low back pain: insights from a novel case-control twin study

BACKGROUND CONTEXT

Previous research has failed to identify strong consistent risk factors for low back pain (LBP). A plausible solution is to conduct hypothesis-generating studies, such as twin case-control surveys.

PURPOSE

To investigate twins' perceptions of the factors responsible for within-pair differences in LBP.

STUDY DESIGN

A case-control twin survey.

PATIENT SAMPLE

Twenty-four twin pairs that were generally and broadly discordant for LBP history.

OUTCOME MEASURES

The participants' perceptions of the factors that could explain within-pair differences in LBP history.

METHODS

Twins were asked to identify the factors responsible for within-pair differences in LBP. Closed questioning collected information on the known risk factors and open-ended questioning was used to reveal novel factors. The frequency of risk factors was presented to investigate the individual's perception of the contribution of factors in the development of their own and/or their twin's experience of LBP.

RESULTS

The most frequent factors reported in the closed questioning related to the physical workload of the lumbar spine, specifically, the engagement in different types of work (n=23/24 pairs, 96%). Types of work included those involving heavy loads, lifting, manual tasks, awkward postures, and gardening. Single trauma or injury and vigorous physical activity participation were perceived as the contributors by 79% (n=19/24 pairs) and 88% (n=21/24 pairs) of the pairs, respectively. Open-ended questioning did not reveal new risk factors for LBP.

CONCLUSIONS

Twins attributed the differences in LBP history to risk factors related to physical workload. Future studies investigating the risk factors for LBP should include valid and comprehensive assessments of these factors.

Repeated primary care consultations for non-specific physical symptoms in children in UK: a cohort study

BACKGROUND

Non-specific physical symptoms (NSPS), such as headache and abdominal pain, are common reasons for children to consult primary care. NSPS represent a significant burden not only on society, but also on health care services, through frequent physician consultations and referrals to secondary care. Research evidence suggests a positive relationship between health and consulting behavior of parents and their children, but research on whether repeated physician consultations for NSPS in children is influenced by parental consultations for NSPS is lacking. The aim was to measure the frequency of repeated physician consultations for NSPS in children, and investigate whether this is influenced by maternal consultations for NSPS.

METHODS

A cohort study of children registered with primary care practices contributing to the Consultation in Primary Care Archive database. Participants were child-mother pairs registered between January 2007 and December 2010. The cohort comprised all children (n = 1437) aged 2 to 16 years who consulted a physician for NSPS in 2009. Mothers' consultations for NSPS were measured between 2007 and 2008. Main outcome measures were repetition and frequency of consultations for NSPS in children (consultations for NSPS in both 2009 and 2010).

RESULTS

Overall, 27% of children had repeated consultations for NSPS. The three most common repeated consultations were for back pain, constipation and abdominal pain. Exposure to maternal consultation for NSPS was associated with 21% increase in consultation frequency for NSPS (adjusted incidence rate ratio 1.21; 95% CI 1.12, 1.31). After adjusting for child age and maternal age, maternal consultation for NSPS was associated with an increased risk of repeated consultations for NSPS in children (relative risk 1.41; 95% CI 1.16, 1.73). This association was also significant for specific NSPS groups including painful, gastrointestinal, and neurologic symptoms.

CONCLUSIONS

Repeated consultation for NSPS is common among children. It is important for primary care physicians and secondary care clinicians, managing children referred from primary care for NSPS, to be aware that consultation for NSPS in mothers is a risk factor for repeated consultations for NSPS among children. More research is needed to uncover exactly how parental health influences health and consulting behavior of children.

Non-specific low back pain in adolescents from the south of Portugal: prevalence and associated factors

BACKGROUND

Low back pain (LBP) is a common condition in children and adolescents, and the prevalence has been increasing over the years. Most cases of LBP are due to non-specific causes; however, the role of these risk factors is still controversial. This study determined the prevalence of LBP in Portuguese adolescents and characterized the associated factors.

METHODS

The design of this study was observational, analytical and cross-sectional. The sample included 966 adolescents from southern Portugal, aged between 10 and 16 years. The assessments included a questionnaire to characterize the presence of LBP, postural habits, body mass index (BMI) and backpack weights and to use a scoliometer to evaluate the presence of scoliosis.

RESULTS

One hundred fifty-two (15.7 %) students had LPB at the present time, 456 (47.2 %) had experienced it in the last year, and 600 (62.1 %) had lifetime prevalence of LBP. Girls have 2.05 more probability of presenting LBP than boys (95 % CI 1.58-2.65; p < 0.001), and older students have a 1.54 greater probability (95 % CI 1.19-1.99; p = 0.001). Students who sit with the spine incorrectly positioned presented 2.49 greater probability of having LBP (95 % CI 1.91-3.2; p < 0.001), students using improper positions for watching TV or playing games have 2.01 greater probabilities (95 % CI 1.55-2.61; p < 0.001), and those who adopt an incorrect standing posture have a 3.39 greater chance of experiencing LBP (95 % CI 2.19-5.23; p < 0.001).

CONCLUSIONS

This study found a high prevalence of LBP in adolescents, with higher values in older students, female students and those who adopted incorrect positions when sitting or standing.

The association between GP consultations for non-specific physical symptoms in children and parents: a case-control study

BACKGROUND

Non-specific physical symptoms (NSPS) such as abdominal pain, headache and musculoskeletal pain are widespread in the community, and are common reasons for visiting a general practitioner (GP). Causes of NSPS are multifactorial, but may include parental influences.

OBJECTIVE

To investigate associations between GP consultations for NSPS in parents and their children.

METHODS

Matched case-control study using GP consultation data from 12 GP practices in the United Kingdom. Participants were 1328 children who consulted a GP for NSPS in 2009 (cases), 3980 controls who consulted a GP in 2009 but not for NSPS, plus parents of cases and controls (n = 8354).

PRIMARY OUTCOME MEASURE

child consultation status for NSPS.

RESULTS

Maternal consultation for NSPS was associated with significantly increased odds of their child consulting for NSPS (odds ratio (OR) 1.51, 95% confidence intervals (CI) 1.33, 1.73); there was no significant association with paternal consultations (OR 0.87, 95% CI 0.71, 1.08). Each additional maternal consultation for NSPS was associated with an increase in the rate ratio for number of consultations for NSPS in the child by 1.03 (95% CI 1.01, 1.05). This overall association was clearest in maternal-child consultations for painful NSPS and for specific bodily systems including gastrointestinal, musculoskeletal and neurologic symptoms.

CONCLUSIONS

Maternal GP consultation for NSPS is associated with increased odds of GP consultations for NSPS in children. This study included a large sample of children and parents and used medical records data which is not subject to recall bias. However, analysis was based on medical records, thus the presence of NSPS not leading to consultations is unknown. Medical practitioners managing children with NSPS need to be aware of this association.

Time trends in single versus concomitant neck and back pain in Finnish adolescents: results from national cross-sectional surveys from 1991 to 2011

Background

Previous studies, in late 20th century, suggest an increase in the prevalence of neck pain and low back pain among children and adolescents, when neck and low back pain were studied separately. This study investigated time trends in adolescent spinal pain between 1991 and 2011 by classifying pain into the following three classes: neck pain alone, low back pain alone, and concomitant neck and low back pain.

Methods

Representative samples of 12 to 18-year-old Finns were sent a questionnaire in 1991, 1999, 2001, 2003, 2005, 2007, 2009 and 2011. Information was gathered about the frequency of neck and low back pain with a six-month recall period. Statistical methods used included descriptive analysis, and generalized linear models.

Results

The total number of respondents in these eight comparable cross-sectional surveys was 51 044 with a response proportion of 64%. The prevalence of concomitant neck and low back pain showed a steady increase from 1991 to 2009/2011; the prevalence almost quadrupled among 12-14-year-olds girls (from 2% to 7.5%), and more than doubled among 12-14-year-old boys (from 1.6% to 3.8%), and among 16-18-year old boys (from 4.2 to 9.9%) and girls (6.9% to 15.9%). The prevalence of neck pain alone only increased in the 1990s (e.g. among 16-18-year-old girls 22.9% in 1991, 29.2% in 1999, and 29.5% in 2011), while the prevalence of low back pain alone remained relatively constant during the last two decades (e.g. among 16-18-year-old girls 4% in 1991, 3.1% in 1999, and 3.7% in 2011).

Conclusions

Concomitant neck and low back pain has constantly increased in the last two decades among adolescents, while single neck pain has only increased in the 1990s. Single low back pain has remained relatively constant. Thus, earlier detected increase in low back pain in the 1990s was explained by the increase in concomitant neck and low back pain. Differences in the time trends in the three pain conditions might suggest, at least partly, different risk factors and aetiology for single- and multisite spinal pain among adolescents. This hypothesis needs further investigations.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2474-15-296) contains supplementary material, which is available to authorized users.

[Nonspecific low back pain in young adults: associated risk factors]

OBJECTIVE

The aim of the study was to evaluate potential risk factors related to low back pain in the daily routines of two sets of youths: individuals complaining of chronic low back pain and a control group.

METHODS

The sample consisted of 198 university-age students (male and female) aged between 18 and 29. In accordance with back pain diagnoses, they were separated into two groups: with or without nonspecific chronic low back pain. Both groups were evaluated by a "blinded" observer with no knowledge to the presence or otherwise of lower back pain. Questionnaires concerning clinical-demographic characteristics, life style, quality of life (SF-36 questionnaire), pain visual analogical scales (VAS), and physical examination were applied.

RESULTS

A univariate analysis showed a statistically significant association (P<0.05) with the presence of low back pain and some factors. There was a negative association between low back pain and the following variables: BMI, health self-assessment, VAS and some SF-36 domains (physical functioning, body pain, general health, vitality, social functioning). There was a positive correlation with the following variables: global pain by VAS, presence of diffuse pain and number of tender points. However, the multivariate analysis showed statistically significant correlations (P<0.05) between low back pain and few variables: global pain VAS and number of tender points.

CONCLUSION

Some variables related to chronic diffuse pain and lower quality of life might be associated to chronic low back pain in young adults. However, longitudinal studies are necessary.

Genetic and environmental influences on non-specific neck pain in early adolescence: a classical twin study

BACKGROUND

Prevalence of neck pain has increased among adolescents. The origins of adult chronic neck pain may lie in late childhood, but for early prevention, more information is needed about its aetiology. We investigated the relative roles of genetic and environmental factors in early adolescent neck pain with a classic twin study.

METHODS

Frequency of neck pain was assessed with a validated pain questionnaire in a population-based sample of nearly 1800 pairs of 11-12-year-old Finnish twins. Twin pair similarity for neck pain was quantified by polychoric correlations, and variance components were estimated with biometric structural equation modelling.

RESULTS

Prevalence of neck pain reported at least once monthly was 38% and at least once weekly 16%, with no significant differences between gender and zygosity. A greater polychoric correlation in liability to neck pain was found in monozygotic (0.67) than for dizygotic pairs (0.38), suggesting strong genetic influences. Model fitting indicated that 68% (95% confidence interval 62-74) of the variation in liability to neck pain could be attributed to genetic effects, with the remainder attributed to unshared environmental effects. No evidence for sex-specific genetic effects or for sex differences in the magnitude of genetic effects was found.

CONCLUSIONS

Genetic and unique environmental factors seem to play the most important roles in liability to neck pain in early adolescence. Future research should be directed to identifying pathways for genetic influences on neck pain and in exploring effectiveness of interventions that target already identified environmental risk factors.

Prevalence of low back pain in children and adolescents: a meta-analysis

BACKGROUND

Low back pain (LBP) is common in children and adolescents, and it is becoming a public health concern. In recent years there has been a considerable increase in research studies that examine the prevalence of LBP in this population, but studies exhibit great variability in the prevalence rates reported. The purpose of this research was to examine, by means of a meta-analytic investigation, the prevalence rates of LBP in children and adolescents.

METHODS

Studies were located from computerized databases (ISI Web of Knowledge, MedLine, PEDro, IME, LILACS, and CINAHL) and other sources. The search period extended to April 2011. To be included in the meta-analysis, studies had to report a prevalence rate (whether point, period or lifetime prevalence) of LBP in children and/or adolescents (≤ 18 years old). Two independent researchers coded the moderator variables of the studies, and extracted the prevalence rates. Separate meta-analyses were carried out for the different types of prevalence in order to avoid dependence problems. In each meta-analysis, a random-effects model was assumed to carry out the statistical analyses.

RESULTS

A total of 59 articles fulfilled the selection criteria. The mean point prevalence obtained from 10 studies was 0.120 (95% CI: 0.09 and 0.159). The mean period prevalence at 12 months obtained from 13 studies was 0.336 (95% CI: 0.269 and 0.410), whereas the mean period prevalence at one week obtained from six studies was 0.177 (95% CI: 0.124 and 0.247). The mean lifetime prevalence obtained from 30 studies was 0.399 (95% CI: 0.342 and 0.459). Lifetime prevalence exhibited a positive, statistically significant relationship with the mean age of the participants in the samples and with the publication year of the studies.

CONCLUSIONS

The most recent studies showed higher prevalence rates than the oldest ones, and studies with a better methodology exhibited higher lifetime prevalence rates than studies that were methodologically poor. Future studies should report more information regarding the definition of LBP and there is a need to improve the methodological quality of studies.

Nature or nurture in low back pain? Results of a systematic review of studies based on twin samples

Twin studies are becoming popular to investigate risk factors for low back pain (LBP) because they consider the genetic factor and allow for more precise estimates of risks. We aimed to identify and summarize the results of studies based on twin samples investigating risk factors for LBP. The MEDLINE, CINAHL, LILACS, Web of Science and EMBASE databases were searched. Prospective and cross-sectional observational studies of LBP involving twins were included. The exposure factors could be genetics (heritability) or environmental such as smoking, alcohol consumption, body mass index and medical history. Pooling was attempted using an inverse variance weighting and fixed effects model. Twenty-seven studies were included. Estimates of heritability effects ranged from 21% to 67%. The genetic component was higher for more chronic and disabling LBP than acute and less disabling LBP. Smoking was significantly associated with LBP [pooled odds ratio (OR) = 3.0; 95% confidence interval (CI) 2.8-3.3] with a longitudinal and a cross-sectional study also identifying a dose-response relationship in people with chronic LBP. Obesity was associated with LBP (pooled OR = 1.9; 95% CI 1.6-2.2) with a cross-sectional study identifying a dose-response relationship. No association between alcohol consumption and LBP was identified. Co-morbidities such as asthma, diabetes and osteoarthritis were associated with LBP (pooled OR ranging from 1.6 to 4.2). The contribution of genetics to LBP appears to be dependent on the severity of the condition. Twin studies could be better used to explore possible causation paths between lifestyle factors, co-morbidities and LBP.

Back pain and body posture evaluation instrument (BackPEI): development, content validation and reproducibility

OBJECTIVES

Following a search conducted in several databases, no instrument was found that jointly evaluates the prevalence of back pain and its associated demographic, social-economic, hereditary, behavioral and postural risk factors. Thus, the present study aims to develop the Back Pain and Body Posture Evaluation Instrument (BackPEI) for school-age children and verify its validity and reproducibility.

METHODS

Twenty-one questions were elaborated to compose the BackPEI instrument, eight experts checked the content validity, and its reproducibility was tested by applying the questionnaire to 260 primary schoolchildren, at two different times with a 7-day interval.

RESULTS

The reproducibility data for the first 20 questions, analyzed using the kappa (k) coefficient, were classified as "very good" (k > 0.8) or "good" (0.6 < k ≤ 0.8). The reproducibility data for the pain intensity question, analyzed using the Wilcoxon test and the intraclass correlation coefficients (ICC), demonstrated that there was no difference between the averages (p = 0.251) and the responses were highly correlated (ICC = 0.937) for these two tests.

CONCLUSIONS

The BackPEI constitutes a valid and reproducible instrument which is relevant for the evaluation of back pain and its associated risk factors.

Twin studies of pain

Twin studies provide a method for estimating the heritability of phenotypes and for examining genetic and environmental relationships between phenotypes. We conducted a systematic review of twin studies of pain, including both clinical and experimental pain phenotypes. Fifty-six papers were included, whereof 52 addressed clinical phenotypes. Of the most comprehensively studied phenotypes, available data indicates heritability around 50% for migraine, tension-type headache and chronic widespread pain, around 35% for back and neck pain, and around 25% for irritable bowel syndrome. However, differences in phenotype definitions make these results somewhat uncertain. All clinical studies relied on dichotomous outcomes and none used pain intensity as continuous phenotype. This is a major weakness of the reviewed studies and gives reason to question their validity with respect to pain mechanisms. Experimental pain studies indicate large differences in heritability across pain modalities. Whereas there is evidence for substantial common genetic risk across many clinical pain conditions, different experimental pain phenotypes appear to be associated with different genetic factors. Recommendations for future research include inclusion of pain intensity scaling and number of pain sites in phenotyping. Furthermore, studies examining the genetic relationships between pain phenotypes, in particular between clinical and experimental phenotypes, should be prioritized.

Pain genetics: past, present and future

Chronic pain is a classic example of gene × environment interaction: inflammatory and/or nerve injuries are known or suspected to be the etiology of most chronic pain syndromes, but only a small minority of those subjected to such injuries actually develop chronic pain. Once chronic pain has developed, pain severity and analgesic response are also highly variable among individuals. Although animal genetics studies have been ongoing for over two decades, only recently have comprehensive human twin studies and large-scale association studies been performed. Here, I review recent and accelerating progress in, and continuing challenges to, the identification of genes contributing to such variability. Success in this endeavor will hopefully lead to both better management of pain using currently available therapies and the development and/or prioritizing of new ones.

Recent advances in the understanding of genetic susceptibility to chronic pain and somatic symptoms

Regional (e.g., low back) and widespread chronic pain disorders are common in the general population and are known to be heritable. Recent research suggests that genetic factors increase the risk of developing chronic pain independent of the site of pain. Candidate gene studies have been conducted on key pathways to elucidate susceptibility genes that are likely to be involved in both the sensory and affective components of pain. Findings have been largely equivocal, predominantly due to small sample size, but larger studies of pain in general population samples are being conducted. Interesting candidate genes from animal models and monogenic pain disorders are beginning to emerge. Recent advances in genetics research have yet to make an impact in the pain field but provide considerable scope for future research efforts.

Management of degenerative disk disease and chronic low back pain

Degenerative disk disease is a strong etiologic risk factor of chronic low back pain (LBP). A multidisciplinary approach to treatment is often warranted. Patient education, medication, and cognitive behavioral therapies are essential in the treatment of chronic LBP sufferers. Surgical intervention with a rehabilitation regime is sometimes advocated. Prognostic factors related to the outcome of different treatments include maladaptive pain coping and genetics. The identification of pain genes may assist in determining individuals susceptible to pain and in patient selection for appropriate therapy. Biologic therapies show promise, but clinical trials are needed before advocating their use in humans.

Long-term effectiveness of a back education programme in elementary schoolchildren: an 8-year follow-up study

The purpose of this study was to investigate the long-term effectiveness of a spine care education programme conducted in 9- to 11-year-old schoolchildren. The study sample included 96 intervention subjects and 98 controls (9- to 11-year-olds at baseline). Intervention consisted of a 6-week school-based back education programme (predominantly biomechanically oriented) and was implemented by a physical therapist. Self-reported outcomes on back care knowledge, spinal care behaviour, self-efficacy towards favourable back care behaviour, prevalence of back and neck pain during the week and fear-avoidance beliefs were evaluated by the use of questionnaires. Post-tests were performed within 1 week after programme completion, after 1 year and after 8 years. Whereas the educational back care programme resulted in increased back care knowledge up to adulthood (P < 0.001), intervention did not change spinal care behaviour or self-efficacy. Pain prevalence figures increased less in the experimental group compared to the controls over the 8-year time span, yet statistical significance was not reached. Dropout analysis revealed spinal pain prevalence rates to be different in both groups throughout the study, including at baseline. Back education at young age did not reinforce fear-avoidance beliefs up to adulthood. Predominantly biomechanical oriented back education in elementary schoolchildren is effective in improving the cognitive aspect of back care up to adulthood, yet not in changing actual behaviour or self-efficacy. The current study does not provide evidence that educational back care programmes have any impact on spinal pain in adulthood. The true long-term impact of school-based spinal health interventions on clinically relevant outcome measures merits further attention.

Lumbar disc degeneration and genetic factors are the main risk factors for low back pain in women: the UK Twin Spine Study

Objective

Low back pain (LBP) is a common musculoskeletal disorder, but it is still unclear which individuals develop it. The authors examined the contribution of genetic factors, lumbar disc degeneration (LDD) and other risk factors in a female sample of the general population.

Material and Methods

A cross-sectional study was conducted among 2256 women (371 and 698 monozygotic and dizygotic twin pairs and 29 sibling pairs and 60 singletons) with a mean age of 50 years (18–84). A self-reported validated questionnaire was used to collect back pain data. Risk factors including body weight, smoking, occupation, physical exercise and MRI assessed LDD were measured. Data analysis included logistic regression and variance decomposition.

Results

The major factors associated with LBP included genetic background, with OR approximately 6 if the monozygotic co-twin had LBP, or 2.2 if she was a dizygotic co-twin. In addition, LDD and overweight were highly significantly (p<0.001) associated with non-specific LBP. The single most important risk factor was the amount of LDD. After adjustment for other risk factors, the individuals who exhibited advanced LDD (90% vs 10%) had 3.2 higher odds of manifesting LBP. The data also showed a significant (p<0.001) genetic correlation between the LBP and LDD measurements, suggesting that approximately 11–13% of the genetic effects are shared by LDD and LBP.

Conclusions

The main risk factors for reported episodes of severe and disabling LBP in UK women include the degree of LDD as assessed by MRI, being overweight and genetic heritability.

Risk factors for the first episode of low back pain in children are infrequently validated across samples and conditions: a systematic review

QUESTION

What risk factors have been identified for the first episode of low back pain in children and adolescents? Have these risk factors been validated?

DESIGN

Systematic review of prospective studies designed to identify possible modifiable and non-modifiable risk factors for the onset of low back pain in children and adolescents.

PARTICIPANTS

School children aged up to 18 years without low back pain at enrolment.

RESULTS

Five studies were included in the review. The included studies varied considerably in methods used to gather data, definitions of low back pain, and recall periods for an episode of low back pain. Forty-seven possible risk factors had been assessed for association with a first episode of low back pain in children. Of these, 13 were significantly associated with a first episode of low back pain. No risk factor was found to be associated with future low back pain in children in more than one study.

CONCLUSION

Inconsistency in definitions of low back pain, pre-defined recall periods, and methods used to collect and analyse data limit conclusions that can be drawn about factors that identify children at risk of developing low back pain. As no risk factor has been validated in independent investigation, we have no certainty that any factor places children at risk of developing low back pain.

Nonspecific low back pain during childhood: a retrospective epidemiological study of risk factors

OBJECTIVES

In contrast to what was believed in the past, nonspecific low back pain is a fairly frequent condition in children, whose pathophysiology remains unclear as yet. Although many factors have been implicated in its development, results are often contradictory.

METHODS

Our study aims to examine most of the reasons investigated in the international literature, as well as the previously unexamined impact of passive smoking in its clinical appearance. It is a retrospective study that investigates the symptom of nonspecific low back pain during a 12-month period before the visit of children to our department. The research included 692 children aged 7.5 to 14 years. The data were collected using a semi-structured questionnaire, which included a mix of open and closed questions, followed by physical examination during their visit.

RESULTS

A total of 153 children were considered to present nonspecific low back pain during the previous year. The determinant factors appear to be greater age, the male sex, larger height, increased weight, dissatisfaction with school chairs, the clinical presentation of back pain in at least 1 parent, and coexisting anatomic orthopedic conditions. On the contrary, the weight of the school bag, the way in which it was carried and participation in sports, as well as the time spent by children in front of the TV or PC playing video or play station games, did not appear to have a statistically significant correlation with its appearance. In general, passive smoking does not appear to be a risk factor (P[r] = 0.341), and does not seem to play a leading role in the etiology of the condition. Furthermore, even the heaviness of parental smoking (over 20 cigarettes a day) does not seem to alter the appearance of the disease. The effect of nonspecific low back pain in children's activities was measured using Hannover Functional Ability and Rolland Morris questionnaires, appropriately modified to childhood, where he found a moderate or severe restriction of activity in 23.52% (score >5) and 19.61% (score >6), respectively.

CONCLUSIONS

The data analysis shows that nonspecific low back pain in children is a benign disorder with an unknown pathophysiological mechanism. Many anthropometric characteristics and environmental factors are implicated, but to a different degree each time. Passive smoking as well as the heaviness thereof does not appeal to play in important role in its clinical presentation. Further investigation is deemed necessary to determine the existence of other risk factors, as well as the level of their participation in the condition's pathophysiology.

What is adolescent low back pain? Current definitions used to define the adolescent with low back pain

Adolescent low back pain (ALBP) is a common form of adolescent morbidity which remains poorly understood. When attempting a meta-analysis of observational studies into ALBP, in an effort to better understand associated risk factors, it is important that the studies involved are homogenic, particularly in terms of the dependent and independent variables. Our preliminary reading highlighted the potential for lack of homogeneity in descriptors used for ALBP. This review identified 39 studies of ALBP prevalence which fulfilled the inclusion criteria, ie, English language, involving adolescents (aged 10 to 19 years), pain localized to lumbar region, and not involving specific subgroups such as athletes and dancers. Descriptions for ALBP used in the literature were categorized into three categories: general ALBP, chronic/recurrent ALBP, and severe/disabling ALBP. Whilst the comparison of period prevalence rates for each category suggest that the three represent different forms of ALBP, it remains unclear whether they represented different stages on a continuum, or represent separate entities. The optimal period prevalence for ALBP recollection depends on the category of ALBP. For general ALBP the optimal period prevalence appears to be up to 12 months, with average lifetime prevalence rates similar to 1-year prevalence rates, suggesting an influence of memory decay on pain recall.

The association between isoinertial trunk muscle performance and low back pain in male adolescents

The literature reports inconsistent findings regarding the association between low back pain (LBP) and trunk muscle function, in both adults and children. The strength of the relationship appears to be influenced by how LBP is qualified and the means by which muscle function is measured. The aim of this study was to examine the association between isoinertial trunk muscle performance and consequential (non-trivial) low back pain (LBP) in male adolescents. Healthy male adolescents underwent anthropometric measurements, clinical evaluation, and tests of trunk range of motion (ROM), maximum isometric strength (STRENGTH) and peak movement velocity (VEL), using an isoinertial device. They provided information about their regular sporting activities, history and family history of LBP. Predictors of "relevant/consequential LBP" were examined using multivariable logistic regression. LBP status was reassessed after 2 years and the change from baseline was categorised. At baseline, 33/95 (35%) subjects reported having experienced consequential LBP. BMI, a family history of LBP, and regularly playing sport were each significantly associated with a history of consequential LBP (p < 0.05). 85/95 (89%) boys participated in the follow-up: 51 (60%) reported no LBP at either baseline or follow-up (never LBP); 5 (6%) no LBP at baseline, but LBP at follow-up (new LBP); 19 (22%) LBP at baseline, but none at follow-up; and 10 (12%) LBP at both time-points (recurrent/persistent LBP). The only distinguishing features of group membership in these small groups were: fewer sport-active in the "never LBP" group); worse trunk mobility, in the "persistent LBP" group, lower baseline sagittal ROM in the "never LBP" and "new LBP" (p < 0.05). Regular involvement in sport was a consistent predictor of LBP. Isoinertial trunk performance was not associated with LBP in adolescents.

Bone health and back pain: what do we know and where should we go?

Bone health is generally not considered in patients who present with chronic back pain. Nonetheless, bone health and back pain share common genetic and environmental correlates suggesting a co-dependence. Evidence exists for a relationship between back pain and impaired bone health. Here we present the evidence, theoretic framework and clinical relevance. Bone health and back pain are important determinants of musculoskeletal health. Back pain experienced in youth is a risk factor for future back pain, while suboptimal bone health during development increases the risk of skeletal fragility in later life. Generally, bone health is not considered in patients with chronic back pain who do not demonstrate other well-recognised bone health risk factors or associated conditions. Nonetheless, evidence suggests that back pain and impaired bone health share common environmental and genetic correlates, indicating that bone health ought to be considered in the context of back pain in otherwise healthy individuals. This review describes the likely mechanisms explaining the relationship between back pain and impaired bone health, evidence concerning the relationship and suggestions for future research. A narrative literature search was conducted using CINAHL, Medline, PubMed and Web of Science electronic databases. A history of back pain is associated with decreased bone mineral density in adults, yet this tends to be site-specific. No studies were identified examining this association in youth, yet the negative effects of childhood skeletal trauma and obesity on bone and spinal health provide indirect evidence for an association. Further research is required to clarify the impact of back pain on bone health at different lifespan stages using prospective cohort designs.