Abstract
AIM
Adolescents with physical disabilities may have co-occurring chronic pain, but the prevalence and specific associated factors are unknown. The aims of this study were to determine (1) the prevalence of chronic pain in adolescents with physical disabilities and (2) whether known correlates of chronic pain in the general population are also present in young people both with physical disability and with chronic pain relative to peers.
METHOD
We conducted a secondary analysis of cross-sectional nationally representative data from the National Longitudinal Study of Adolescent to Adult Health. Multivariate linear regression analysis was used to identify demographic and psychosocial factors associated with chronic pain.
RESULTS
A total of 989 (4.3%) adolescents reported physical disabilities. They had a significantly higher rate of pain (27.2%) compared with able-bodied peers (15.6%, χ2=86.3550, p<0.001). There was no significant interaction between physical disability status and chronic pain in relation to depressive symptoms, anxiety, or insomnia.
INTERPRETATION
Adolescents with physical disabilities experience chronic pain at a significantly higher rate than able-bodied peers, but the comorbidity of physical disability and chronic pain is not related to depression, anxiety, or insomnia. Evaluation of chronic pain and tailored pain interventions need to be developed for this population.
It is estimated that 5.8% of children and adolescents in the USA have physical disabilities.1 As a subpopulation, they have been identified as a global health priority by UNICEF.2 Disability can conceptually be defined as ‘difficulty or dependency in carrying out activities essential to independent living’.3 The physical characteristics of these disabilities may comprise difficulty with gross-motor skills such as walking; difficulty with fine-motor skills such as writing or eating; or altered muscle tone, paralysis, loss of, or inability to use, one or more limbs.
Limited available literature shows that children with physical disabilities are known to have worse physical and psychological health outcomes and poorer social support than able-bodied comparison groups.4 A common symptom experienced by young people with physical disabilities is pain. Although chronic pain is well documented as having significant physical, psychological, and social impact among non-disabled young people, little research has been conducted to understand the prevalence and impact of chronic pain in young people with physical disabilities.5 The limited evidence suggests that young people with physical disabilities may be at greater risk of having chronic pain6; and, given the nature of physical disabilities, these young people commonly report pain in more than one bodily site.7 However, previous studies are limited by small sample sizes, and inclusion of only one specific physical disability (e.g. cerebral palsy8 or neuromuscular disease),9 make any conclusions about pain in this population very preliminary or disability-specific. This has hindered the development of interventions to manage pain in the broader population of adolescents with physical disabilities. Epidemiological research is necessary to better characterize the prevalence of pain and associated factors in adolescents with physical disabilities in order to guide future assessment and intervention efforts in this at-risk population.
In addition to general prevalence estimates, identifying the demographic and psychosocial factors that may be associated with chronic pain in this specific population of young people with physical disabilities is important for developing preventive interventions targeted to those at risk for co-occurring chronic pain. Such interventions are needed to help alleviate the impact of the co-occurrence of chronic pain and physical disabilities, decrease impaired functioning,6 and reduce the economic, emotional, and social burden that is well known to this population during adulthood.
A range of demographic and psychosocial factors have been found to be associated with chronic pain in able-bodied populations in several pain conditions (e.g. musculoskeletal pain,10 low back pain,11 widespread pain,12 and postsurgical pain).13 Specifically, certain demographic characteristics (like female sex and older age)14 and clinical factors (higher rates of insomnia,15 increased levels of anxiety,16 and more depressive symptoms)17 have been found to be associated with pain and functional disability in young people.
Because young people with disabilities have unique characteristics and needs, it is unknown whether similar demographic and psychosocial factors would be associated with chronic pain in this population. For example, neurological impairments may disrupt sleep, muscular stiffness can be increased because of the disease or the use of a wheelchair, and depression and anxiety symptoms may be increased owing to poorer social relationships and stigma. All of these factors may in turn influence the experience of chronic pain.
To characterize rates and correlates of chronic pain in young people with physical disabilities, we used cross-sectional data from the National Longitudinal Study of Adolescent to Adult Health (Add Health)18 for secondary data analysis on a broad, population-level scale. This is the first nationally representative study to examine chronic pain in adolescents with physical disabilities. Our primary aim was to determine prevalence rates of chronic pain and its associated factors, including socio-demographic factors (age, sex, ethnic group, and income), perceived general health, and psychosocial factors (anxiety, depressive symptoms, insomnia) among adolescents with physical disabilities compared with adolescents without physical disabilities in the USA. Our secondary aim was to determine whether known correlates of chronic pain in the general population are also important correlates of chronic pain among adolescents with physical disabilities. Specifically, on the basis of available literature in pediatric chronic pain, we tentatively hypothesized that young people both with physical disabilities and with chronic pain would have significantly higher depressive symptoms, anxiety symptoms, and insomnia, compared with young people with physical disabilities without chronic pain or able-bodied young people.
METHOD
Procedures
We used data from the National Longitudinal Study of Adolescent to Adult Heath (Add Health). Add Health is a nationally representative sample of adolescents, living and attending school in the USA.18 Add Health uses a complex, multistage sample design to provide data that is nationally representative of the adolescent population in the USA. Further information on Add Health is publicly available online (http://www.cpc.unc.edu/projects/addhealth). Our current study uses data from Add Health’s Wave I, which was collected through in-home interviews, from 1994 to 1995. Data collection and procedures were approved by the Institutional Review Board of the University of North Carolina. Written informed consent was obtained before the interviews. The present secondary analysis was also reviewed and approved by the Institutional Review Board at Seattle Children’s Hospital.
Add Health is unique in gathering extensive information about participants’ socio-demographic characteristics and health, including physical disabilities, chronic pain, insomnia, and mental health symptoms. Thus, Add Health provides a rich environment to study factors associated with physical disabilities in participants. So far, two studies on physical disabilities have been published using the Add Health database: Cheng and Udry19 reported on sexual behaviors, while Queirós et al.20 reported on socio-economic outcomes of adolescents with physical disabilities. However, no study on chronic pain among adolescents with physical disabilities in the Add Health database has yet been reported.
Measures
Sample characteristics and demographics
We extracted parent-reported data on socio-demographic variables and other sample characteristics including sex, age, ethnic group (white, non-Hispanic, black, non-Hispanic, Hispanic, or other), parental income (US dollars), and physical aids used (i.e. braces, artificial limbs, canes, crutches or walkers, prescription shoes, and wheelchairs).
Physical disabilities
Adolescents with physical disabilities are identified in Add Health by four self-reported screening questions: (1) ‘do you have any difficulty using your hands, arms, legs, or feet because of a permanent physical condition?’; (2) ‘do you use a cane, crutches, walker, medically prescribed shoes, wheelchair, or scooter to get around because of a permanent physical condition?’; (3) ‘do you use a brace for your hand, arm, leg, or foot because of a permanent physical condition?’; and (4) ‘do you use an artificial hand, arm, leg, or foot?’. In total, 898 participants responded ‘yes’ to any of these questions and were identified as having a physical disability.
Chronic pain
Chronic pain was identified by asking participants to self-rate the frequency of each of the following types of pain occurring over the previous 12 months: (1) headache, (2) stomach ache, and (3) aches, pain, or soreness in muscles or joints. These are the most common types of chronic pain in children and adolescents. The response options included ‘never’, ‘just a few times’, ‘about once a week’, ‘almost every day’, ‘every day’, and ‘refused’. We classified chronic pain as pain occurring ‘almost every day’ or ‘every day.’ This conservative way of coding chronic pain has been used in previous studies with the Add Health sample.21
Anxiety
Anxiety symptoms were measured by asking participants whether they had each of the following physiological symptoms of anxiety in the previous year: (1) felt hot all over suddenly, for no reason, (2) cold sweats, (3) chest pains, (4) fearfulness, and (5) trouble relaxing. Responses to each symptom were measured on a 0 to 4 Likert scale ranging from ‘never’ to ‘every day.’ Scores were summed to provide a range of 0 to 20, with higher scores indicating higher levels of anxiety. This measure of anxiety has been used in previous studies with the Add Health sample.21
Depressive symptoms
Depressive symptoms were measured using the 20-item Center for Epidemiological Studies-Depression Scale22 completed by participants. Responses to each of the 20 items were recorded on a Likert scale ranging from ‘never/rarely’ to ‘most/all of the time’ about symptoms experienced during the previous week. Likert scores were summed to provide a range of 0 to 60 with higher scores indicating more depressive symptoms.
Insomnia
Insomnia was assessed by asking participants whether they had trouble falling asleep or staying sleep. Those that reported ‘every day’ or ‘almost every day’ during the previous year were classified as having insomnia symptoms, similar to other studies.23
Statistical analyses
Data analyses were conducted using the survey package contained in Stata version 12.1 (StataCorp College Station, TX, USA). As recommended, we used sampling weights, regional stratification, and primary sampling unit information to provide nationally representative estimates from the Add Health database. Consequently, descriptive statistics are presented as weighted percentages, means, and linearized standard errors. To address our primary aim, we first conducted bivariate analyses to compare rates of chronic pain between adolescents with and without physical disabilities using survey-adjusted Pearson χ2 tests for categorical variables and Wald tests for continuous variables. To address the secondary aim, we conducted three linear regression analyses to test whether the presence of both a physical disability and chronic pain in young people was associated with significantly higher depressive symptoms, anxiety symptoms, and rates of insomnia after controlling for the effects of sex, age, ethnic group, and income.
RESULTS
Socio-demographic and clinical characteristics
Age, sex, ethnic group, and income
The total sample consisted of 18 924 adolescents (mean age 16y 0 mo) who were representative of the US adolescent population in 1995 to 1996, with 9288 (50.9%) identified as male and 9644 (64.9%) identified as white, non-Hispanic. The sample contained 898 participants with physical disabilities (4.3%). Participants with physical disabilities had socio-demographic characteristics similar to able-bodied adolescents (see Table I).
Table I.
Socio-demographic and clinical characteristics of the adolescents
| Full sample (n=18 924) | Physical disabilities (n=898) | No physical disabilities (n=18 026) | p | |
|---|---|---|---|---|
| Estimated US population | 22 213 733 | 958 609 | 21 255 124 | |
| Weighted % (SEM) | – | 4.3 (0.5) | 95.7 (0.5) | |
| Mean age, y:mo (SEM) | 16:0 (0:1) | 16:5 (0:1) | 16:0 (0:1) | 0.005 |
| Female sex, % (SEM) | 49.1 (0.6) | 48.8 (3.5) | 49.1 (0.5) | 0.930 |
| Ethnic group, % (SEM) | 0.320 | |||
| White, non-Hispanic | 64.9 (2.9) | 64.7 (5.3) | 64.9 (2.9) | |
| Black, non-Hispanic | 15.5 (2.0) | 11.2 (2.1) | 15.7 (2.1) | |
| Hispanic | 12.1 (1.7) | 16.0 (5.2) | 11.9 (1.7) | |
| Other | 7.5 (0.8) | 8.1 (1.3) | 7.5 (0.8) | |
| Mean parental income, US$ (SEM) | 45 189 (1704) | 44 647 (3300) | 45 213 (1727) | 0.860 |
| Mean anxiety symptoms, (SEM) | 2.3 (0) | 2.9 (0.2) | 2.3 (0) | 0.001 |
| Mean depressive symptoms (SEM) | 11.6 (0.1) | 13.2 (0.5) | 11.6 (0.1) | 0.0008 |
| Insomnia, % (SEM) | 10.3 (0.3) | 14.5 (1.8) | 10.1 (0.3) | 0.007 |
| Chronic pain, % (SEM) | 15.6 (0.5) | 27.2 (2.9) | 15.1 (0.5) | <0.0001 |
| Brace use | 2.5 (0.2) | 28.5 (3.6) | 1.3 (0.1) | <0.0001 |
| Artificial limb use | 0.2 (0.1) | 2.0 (0.7) | 0.1 (0.0) | <0.0001 |
Source: National Longitudinal Study of Adolescent to Adult Health. SEM, linearized standard error of the mean.
Types of pain and assistive devices used
Regarding the type of chronic pain, the most common locations were pain in muscles and joints (16.5%), headaches (12.2%), and stomach aches (6.4%). Concerning the assistive devices used by the participants with physical disabilities, we found that 28.5% used braces, 3.6% used prescription shoes, 3.4% used crutches or a walker, 3.1% used a wheelchair, 2% had an artificial limb, and 0.5% needed a cane. Use rates were similar between those with and without chronic pain for all the devices except for braces (chronic pain 36.0%, no chronic pain 25.7%; p=0.029) and prescription shoes (chronic pain 6.6%, no chronic pain 2.5%; p=0.023).
Aim 1: prevalence of chronic pain
In unadjusted bivariate analysis, young people with physical disabilities had a significantly higher rate of chronic pain compared with able-bodied young people (27.2% versus 15.1%; χ2=86.355, p<0.0001). Furthermore, young people with physical disabilities also had higher rates of depressive symptoms (mean score 13.2 vs 11.6; F=11.8, p=0.0008), anxiety symptoms (mean score 2.9 vs 2.3; F=10.71, p=0.001), insomnia (14.5% vs 10.1%; χ2=16.48, p=0.007), and were more likely to rate their general health as poor (11.3% vs 6.8%; χ2=23.56, p=0.001) compared with able-bodied young people (see Table I).
Aim 2: correlates associated with chronic pain and physical disabilities
In the regression analyses, we found main effects of having chronic pain on increased rates of depression, insomnia, and anxiety symptoms, controlling for demographics. However, contrary to hypotheses, there was not a main effect for having a physical disability on depressive, insomnia, and anxiety symptoms, nor was there an interaction effect between physical disabilities and chronic pain. This suggests that young people with both problems did not report greater depression, anxiety, or insomnia relative to young people with physical disabilities without chronic pain or able-bodied young people.
DISCUSSION
In the present study, we sought to describe the prevalence of chronic pain and its associated correlates in a nationally representative sample of adolescents with physical disabilities. Consistent with our primary hypothesis, the prevalence of chronic pain in adolescents with physical disabilities was almost double that of able-bodied adolescents (27.2% vs 15.1%). Rates of chronic pain found in able-bodied adolescents were consistent with estimates found broadly in the pediatric pain literature (11–38%)24 and rates of chronic pain found in the sample with disabilities were also consistent with a study that found that 27% of a sample of young people with cerebral palsy (n=248) had pain problems.8 Furthermore, we also determined that adolescents with physical disabilities had higher rates of anxiety, depression, insomnia, and poorer general health compared with able-bodied adolescents (aim 1). These results provide both novel and important epidemiological data on these vulnerable young people, as previous studies were limited by small sample sizes.
Our secondary aim examined known correlates of chronic pain in the whole sample of adolescents with and without physical disabilities to detect whether young people with both physical disabilities and chronic pain were at risk for more psychosocial symptoms. After controlling for other demographic factors, having chronic pain was associated with higher symptoms of depression and anxiety and higher rates of insomnia. However, we failed to detect a main effect for having a physical disability or a significant interaction between chronic pain and physical disability. Thus, our hypothesis that young people with physical disabilities and chronic pain would be at risk for greater associated psychosocial symptoms was not supported. Further research is needed to understand why minorities differ from white participants and what is the role of economic income.
Taken together, the pattern of findings detected in this study provides preliminary evidence that chronic pain is a common consequence of having a physical disability. This lends support for future research on extending multidisciplinary, evidence-based pediatric pain interventions to young people with physical disabilities. However, although as a group young people with physical disabilities had higher rates of psychosocial symptoms than able-bodied young people, the co-occurrence of chronic pain did not place them at particular increased risk compared with young people with physical disabilities without co-occurring chronic pain. It will be important in future research to also assess other relevant areas not measured in this study such as fatigue, eating and drinking issues, neurocognitive impairment, and communication, which may also increase risk for psychosocial symptoms.
On the other hand, some findings of the association between insomnia and pain have been reported in a previous smaller study (n=505), which found that pain was the strongest predictor for sleep problems in a sample of children and adolescents with physical disabilities (e.g. cerebral palsy, spina bifida, muscular dystrophy), as reported by their parents.25 A comprehensive assessment of sleep problems including both physiological sleep disorders (e.g. sleep-disordered breathing) and behavioral sleep disorders (e.g. insomnia) is warranted in young people with physical disabilities and chronic pain.
The present study has certain limitations that should be considered when interpreting the results. First, we used cross-sectional data, so no inferences on cause and effect relationships could be made. Second, some information that would have allowed us to make more precise conclusions was not available. For example, there was limited information about pain within this large data set, and it did not include assessments of pain intensity, the duration of pain, or pain extent (the number of bodily areas with pain reported on a body map). There was also limited information about the physical disability such as diagnoses, the adolescent’s current treatments, or a functioning index. However, as a proxy for functioning, we do present the information we have available (e.g. knowledge that all the participants were able to attend school, and specific assistive devices used). Without these key data, it is impossible to determine the degree to which pain affects the daily life of young people with physical disabilities, which is critical for determining the extent of pain-specific treatment needed for the population of adolescents with physical disabilities. It also must be acknowledged that the sample is representative of the US population, but generalizability beyond that is unknown. Furthermore, the age of the data warrants comment, as Wave I data in Add Health were collected in 1994 to 1995. However, given the lack of research on pain in young people with physical disabilities, it is important to use available, if older, data sources. Finally, the conservative approach used to classify pain as chronic may have led to lower rates of chronic pain and missed associations between the variables. Future longitudinal research considering pain intensity and location in young people with physical disabilities and specific diagnoses is warranted.
These results suggest that young people with disabilities are at risk for chronic pain and that they may have different needs for pain assessment and management. Of greatest importance, findings show that adolescents with physical disabilities experience chronic pain at higher rates than the general adolescent population. Thus, chronic pain assessment should be a routine aspect of clinical care of adolescents with physical disabilities and referral to multidisciplinary pediatric pain clinics should be considered for pain management. Findings from this study also have implications for tailoring interventions towards young people with physical disabilities. It would be crucial to determine the most effective techniques to use. For example, a study with adolescents with spina bifida and neuromuscular disease (n=70) found that psychological functioning (anxiety, depression, and positive affect) was related to social support from family members but not from friends.4 Thus, the nuances of these conditions should be well-studied before assuming that the techniques (or treatment goals) that work well for other clinical populations are going to work in the same way for adolescents with physical disabilities.
In conclusion, chronic pain and its correlates are important problems for adolescents with physical disabilities, as they are at higher risk of having chronic pain than other young people. The unique characteristics of this population call for further studies of the specific risk factors and correlates of chronic pain in adolescents with physical disabilities, which in turn could direct the development and testing of new treatments targeting their specific needs.
Table II.
Multivariate associations of pain and physical disability with depressive symptoms
| Variable | Coefficient (β) | Standard error | t | P>|t| | 95% CI |
|---|---|---|---|---|---|
| Pain | 4.43 | 0.30 | 14.65 | <0.001 | 3.83–5.03 |
| Disability | 0.77 | 0.50 | 1.55 | 0.123 | −0.21 to 1.76 |
| Age | 0.46 | 0.05 | 9.10 | <0.001 | 0.36–0.56 |
| Sex | 1.62 | 0.19 | 8.38 | <0.001 | 1.24–2.01 |
| Ethnic group | |||||
| Black | 1.40 | 0.29 | 4.83 | <0.001 | 0.83–1.98 |
| Hispanic | 1.90 | 0.35 | 5.43 | <0.001 | 1.21–2.59 |
| Other | 1.65 | 0.41 | 4.00 | <0.001 | 0.83–2.47 |
| Income | −0.013 | 0.002 | −5.95 | <0.001 | −0.02 to −0.01 |
| Constant | 2.68 | 0.80 | 3.37 | 0.001 | 1.10–4.25 |
The reference category for sex is female and for ethnic group is white. No interaction effects between having chronic pain and a physical disability were found.
Table III.
Multivariate associations of pain and physical disability with insomnia symptoms
| Variable | Coefficient (β) | Standard error | t | P>|t| | [95% CI] |
|---|---|---|---|---|---|
| Pain | 0.16 | 0.02 | 10.75 | <0.001 | 0.13–0.19 |
| Disability | 0.01 | 0.02 | 0.66 | 0.510 | −0.02 to 0.04 |
| Age | <−0.01 | <0.01 | −0.66 | 0.511 | −0.00 to 0.00 |
| Sex | 0.01 | 0.01 | 1.14 | 0.257 | −0.01 to 0.02 |
| Ethnic group | |||||
| Black | −0.01 | 0.01 | −1.50 | 0.137 | −0.03 to 0.00 |
| Hispanic | <−0.01 | 0.01 | −0.38 | 0.704 | −0.02 to 0.02 |
| Other | −0.01 | 0.01 | −0.80 | 0.424 | −0.04 to 0.02 |
| Income | <−0.01 | <0.01 | −4.07 | <0.001 | −0.00 to −0.00 |
| Constant | 0.10 | 0.03 | 3.44 | 0.001 | 0.04–0.16 |
The reference category for sex is female and for ethnic group is white. No interaction effects between having chronic pain and a physical disability were found.
Table IV.
Multivariate associations of pain and physical disability with anxiety symptoms
| Variable | Coefficient (β) | Standard error | t | P>|t| | [95% CI] |
|---|---|---|---|---|---|
| Pain | 1.59 | 0.09 | 17.45 | <0.001 | 1.41–1.77 |
| Disability | 0.12 | 0.12 | 0.94 | 0.348 | −0.13 to 0.36 |
| Age | −0.01 | 0.02 | −0.82 | 0.412 | −0.04 to 0.02 |
| Sex | 0.39 | 0.05 | 7.61 | <0.001 | 0.29–0.49 |
| Ethnic group | |||||
| Black | −0.08 | 0.08 | −1.01 | 0.313 | −0.24 to 0.08 |
| Hispanic | 0.04 | 0.08 | 0.56 | 0.577 | −0.11 to 0.20 |
| Other | 0.25 | 0.09 | 2.84 | 0.005 | 0.08–0.43 |
| Income | <−0.01 | <0.01 | −2.56 | 0.012 | −0.00 to −0.00 |
| Constant | 2.05 | 0.25 | 8.32 | <0.001 | 1.56–2.54 |
The reference category for sex is female and for ethnic group is white. No interaction effects between having chronic pain and a physical disability were found.
What this paper adds.
Chronic pain and its correlates are important problems for adolescents with physical disabilities.
These adolescents present with higher rates of chronic pain than other young people.
Chronic pain is associated with increased levels of depressive symptoms, anxiety, and insomnia regardless of disability status.
Acknowledgments
This research uses data from Add Health, a program project directed by Kathleen Mullan Harris and designed by J Richard Udry, Peter S Bearman, and Kathleen Mullan Harris at the University of North Carolina at Chapel Hill, and funded by grant P01-HD31921 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, with cooperative funding from 23 other federal agencies and foundations. Special acknowledgment is due to Ronald R Rindfuss and Barbara Entwisle for assistance in the original design. Information on how to obtain the Add Health data files is available on the Add Health website (http://www.cpc.unc.edu/addhealth). No direct support was received from grant P01-HD31921 for this analysis. The work of RdlV work is supported by a Beatriu de Pinós Postdoctoral Fellowship (2014 BP-A 00009) granted by the Agency for Administration of University and Research Grants (AGAUR). TMP was partly supported by National Institutes of Health 2K24HD060068. The authors have stated that they had no interests that might be perceived as posing a conflict or bias.
ABBREVIATIONS
- Add Health
National Longitudinal Study of Adolescent to Adult Health
References
- 1.Merrick J, Carmeli E. A review on the prevalence of disabilities in children. Internet J Pediatr Neonatol. 2003;4:1–8. [Google Scholar]
- 2.Gottlieb CA, Maenner MJ, Cappa C, Durkin MS. Child disability screening, nutrition, and early learning in 18 countries with low and middle incomes: data from the third round of UNICEF’s Multiple Indicator Cluster Survey (2005–06) Lancet. 2009;374:1831–9. doi: 10.1016/S0140-6736(09)61871-7. [DOI] [PubMed] [Google Scholar]
- 3.Pope AM, Tarlov AR, editors. Disability in America: Toward a National Agenda for Prevention. Washington, DC: National Academy Press; 1991. [Google Scholar]
- 4.Wilson S, Washington LA, Engel JM, Ciol MA, Jensen MP. Perceived social support, psychological adjustment, and functional ability in youths with physical disabilities. Rehabil Psychol. 2006;51:322–30. [Google Scholar]
- 5.Miró J, Castarlenas E, de la Vega R, et al. Validity of three rating scales for measuring pain intensity in youths with physical disabilities. Eur J Pain. 2016;20:130–7. doi: 10.1002/ejp.704. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Ehde DM, Jensen MP, Engel JM, Turner JA, Hoffman AJ, Cardenas DD. Chronic pain secondary to disability: a review. Clin J Pain. 2003;19:3–17. doi: 10.1097/00002508-200301000-00002. [DOI] [PubMed] [Google Scholar]
- 7.Miró J, de la Vega R, Tomé-Pires C, et al. Pain extent and function in youth with physical disabilities. J Pain Res. 2017;10:113–20. doi: 10.2147/JPR.S121590. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Findlay B, Switzer L, Narayanan U, Chen S, Fehlings D. Investigating the impact of pain, age, Gross Motor Function Classification System, and sex on health-related quality of life in children with cerebral palsy. Dev Med Child Neurol. 2016;58:292–7. doi: 10.1111/dmcn.12936. [DOI] [PubMed] [Google Scholar]
- 9.Engel JM, Kartin D, Carter GT, Jensen MP, Jaffe KM. Pain in youths with neuromuscular disease. Am J Hosp Palliat Care. 2009;26:405–12. doi: 10.1177/1049909109346165. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Huguet A, Tougas ME, Hayden J, McGrath PJ, Stinson JN, Chambers CT. Systematic review with meta-analysis of childhood and adolescent risk and prognostic factors for musculoskeletal pain. Pain. 2016;157:2640–56. doi: 10.1097/j.pain.0000000000000685. [DOI] [PubMed] [Google Scholar]
- 11.Akdag B, Cavlak U, Cimbiz A, Camdeviren H. Determination of pain intensity risk factors among school children with nonspecific low back pain. Med Sci Monit. 2011;17:PH12–5. doi: 10.12659/MSM.881378. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Mikkelsson M, El-Metwally A, Kautiainen H, Auvinen A, Macfarlane GJ, Salminen JJ. Onset, prognosis and risk factors for widespread pain in schoolchildren: a prospective 4-year follow-up study. Pain. 2008;138:681–7. doi: 10.1016/j.pain.2008.06.005. [DOI] [PubMed] [Google Scholar]
- 13.Pagé MG, Stinson J, Campbell F, Isaac L, Katz J. Identification of pain-related psychological risk factors for the development and maintenance of pediatric chronic postsurgical pain. J Pain Res. 2013;6:167–80. doi: 10.2147/JPR.S40846. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Martin AL, McGrath PA, Brown SC, Katz J. Children with chronic pain: impact of sex and age on long-term outcomes. Pain. 2007;128:13–9. doi: 10.1016/j.pain.2006.08.027. [DOI] [PubMed] [Google Scholar]
- 15.Finan PH, Goodin BR, Smith MT. The association of sleep and pain: an update and a path forward. J Pain. 2013;14:1539–52. doi: 10.1016/j.jpain.2013.08.007. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Simons LE, Sieberg CB, Claar RL. Anxiety and impairment in a large sample of children and adolescents with chronic pain. Pain Res Manag. 2012;17:93–7. doi: 10.1155/2012/420676. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Kashikar-Zuck S, Goldschneider KR, Powers SW, Vaught MH, Hershey AD. Depression and functional disability in chronic pediatric pain. Clin J Pain. 2001;17:341–9. doi: 10.1097/00002508-200112000-00009. [DOI] [PubMed] [Google Scholar]
- 18.Harris KM, Halpern CT, Whitsel E, et al. The National Longitudinal Study of Adolescent to Adult Health: research design [Internet] Chapel Hill, NC: Add Health; 2009. [accessed 9 February 2017]. Available at: http://www.cpc.unc.edu/projects/addhealth/design. [Google Scholar]
- 19.Cheng MM, Udry JR. Sexual behaviors of physically disabled adolescents in the United States. J Adolesc Health. 2002;31:48–58. doi: 10.1016/s1054-139x(01)00400-1. [DOI] [PubMed] [Google Scholar]
- 20.Queirós FC, Wehby GL, Halpern CT. Developmental disabilities and socioeconomic outcomes in young adulthood. Public Health Rep. 2015;130:213–21. doi: 10.1177/003335491513000308. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Noel M, Groenewald CB, Beals-Erickson SE, Gebert JT, Palermo TM. Chronic pain in adolescence and internalizing mental health disorders: a nationally representative study. Pain. 2016;157:1333–8. doi: 10.1097/j.pain.0000000000000522. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Radloff LS. The CES-D Scale: a self-report depression scale for research in the general population. Appl Psychol Meas. 1977;1:385–401. [Google Scholar]
- 23.Roane BM, Taylor DJ. Adolescent insomnia as a risk factor for early adult depression and substance abuse. Sleep. 2008;31:1351–6. [PMC free article] [PubMed] [Google Scholar]
- 24.King S, Chambers CT, Huguet A, et al. The epidemiology of chronic pain in children and adolescents revisited: a systematic review. Pain. 2011;152:2729–38. doi: 10.1016/j.pain.2011.07.016. [DOI] [PubMed] [Google Scholar]
- 25.Hemmingsson H, Stenhammar AM, Paulsson K. Sleep problems and the need for parental night-time attention in children with physical disabilities. Child Care Health Dev. 2009;35:89–95. doi: 10.1111/j.1365-2214.2008.00907.x. [DOI] [PubMed] [Google Scholar]