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.

Characteristics of neck pain associated with adolescent headache.

The objective of the study was to find out what kind of neck pain (NP) is associated with headache (HA) and with various headache variables: frequency, type, intensity, disturbance, and relief with analgesics. A population-based sample of 12-year-olds with and without HA (n = 304) was followed for 4 years. At the age of 16 years, NP was evaluated on the basis of self-reported symptoms and a thorough physical examination of the neck region. Both self-reported and measured NP were associated with HA variables. Co-occurrent NP was found in adolescents with migraine as often as in those with tension-type HA. Especially, muscle pain and intensive, frequent NP were associated with disturbing HA unresponsive to analgesics. The study indicates that concomitant NP should be considered in adolescent HA sufferers, and a thorough cervical and muscle evaluation is recommended when planning the treatment of HA.

Outcome of headache frequency in adolescence.

Only a few studies have been published of the outcome of adolescent headache (HA). The aim of this study was to examine the predictors of the outcome of headache frequency. A population-based sample of 13-year-olds with or without HA (N=228) was followed to the age of 16 years. HA was classified on the basis of a face-to-face interview and clinical examination. The outcomes of monthly HA (>1/month) and non-frequent HA (0-1/month) were studied. Frequent use of analgesics, female gender and multiple non-headache pain predicted the persistence of monthly HA (>1/month). Significant predictors for worsening non-frequent HA (from 0 to 1/month to >1/month) were female gender, consistent migraine and high basic educational level of one parent. Adolescents frequently using analgesics constitute a risk group for a poor outcome of HA. Especially girls meeting this criterion should be considered a target group in the planning and implementing of preventive measures.

Widespread pain among 11-year-old Finnish twin pairs.

OBJECTIVE: To examine the prevalence of widespread musculoskeletal pain (WSP) symptoms in 11-year-old Finnish twins and to determine the relative role of genetic and environmental factors in the etiology of WSP. METHODS: Data on current pain items were collected from 1995 to 1998 from a national sample of Finnish families with 11-year-old twins born between 1984 and 1987. The presence of WSP was determined using a validated questionnaire method. Pairwise similarity was computed for 583 monozygotic (MZ) pairs, 588 same-sex dizygotic (DZ) pairs, and 618 opposite-sex DZ twin pairs. Variance components for genetic and environmental factors were estimated using biometric structural equation modeling techniques. RESULTS: The prevalence of WSP was 9.9%, with no sex difference. The majority of twin pairs with WSP were discordant. The tetrachoric correlations for male MZ (r = 0.38), male DZ (r = 0.37), female MZ (r = 0.59), female DZ (r = 0.54), and opposite-sex pairs (r = 0.43) showed little difference by zygosity. Female pairs were more concordant than male pairs among both MZ and DZ twins. Biometric model-fitting indicated that genetic factors did not account for the pattern of twin similarity. Among boys 35%, and among girls 56%, of the variation in liability to WSP could be attributed to shared familial environmental effects. The remainder was attributed to unshared environmental effects. CONCLUSION: Genetic factors seem to play at most a minor role in WSP in 11-year-old twins, and environmental factors shared by family members account for a substantial proportion of the variability in WSP.

Neck or shoulder pain and low back pain in Finnish adolescents.

The aim of this study was to investigate the prevalence and determinants of self-reported neck or shoulder pain (NSP) and low back pain (LBP) among 12-18-year-olds. A questionnaire was mailed to a nationally representative sample of 11,276 12-, 14-, 16- and 18-year-olds in 1991. The response rate was 77%. NSP was perceived at least once a week by 15% of 12-18-year-olds and LBP by 8%. Both symptoms were more prevalent among girls than among boys, and the prevalence increased with age. Among the determinants investigated, the number of perceived psychosomatic symptoms had the strongest association with NSP and LBP. Our study confirmed the co-morbidity of NSP and LBP, and indicated that NSP is more frequent than believed among 16-18-year-old girls. The strong association of psychosomatic symptoms with NSP and LBP suggests that the latter two pain states could be more psychosomatic than nociceptive in character.

Widespread pain and neck pain in schoolchildren. A prospective one-year follow-up study.

The aims of this study were to prospectively follow up population-based cohorts of children with widespread pain, children with neck pain and pain-free children, in order to evaluate 1-y changes in pain symptoms and to evaluate predictors for persistent widespread pain and for the change of neck pain to widespread pain. A structured pain questionnaire, the Children's Depression Inventory, and a sleep questionnaire were completed by the pre-adolescent cohorts, and clinical evaluation with tender point palpation and pain threshold measurements was carried out in both years. The Child Behavior Checklist, the Teacher's Report Form and a sociodemographic questionnaire were completed at baseline. More children in the 2 pain cohorts reported pain at follow-up than did controls (p < 0.0001). Children with persistent widespread pain had lower pain thresholds compared with those whose pain classification changed. In the neck pain group, 19 (20.4%) reported widespread pain at follow-up. Although depressive symptoms and sleep problems were associated with the change of neck pain to widespread pain, neither they nor other measured factors showed independent explanatory power in multiple logistic regression analysis. In conclusion, fluctuation of pain symptoms occurred mainly among pain cohorts. Depressive and sleep problems may have an effect on the spreading of regional neck pain to widespread pain. Pain threshold measurement and evaluation of depressive and sleep problems may be useful tools for secondary prevention of musculoskeletal pain in pre-adolescents.

Recurrent low back pain and early disc degeneration in the young.

STUDY DESIGN: A prospective 9-year follow-up study involving randomized matched subgroups of 15-year-old schoolchildren with or without low back pain at baseline. OBJECTIVES: To evaluate the long-term persistence of initially reported recurrent low back pain, and to examine the significance of abnormalities found in magnetic resonance imaging of lumbar discs in individuals 15 and 18 years of age as possible contributors to persistently recurrent low back pain. SUMMARY OF BACKGROUND DATA: In surveys among children and teenagers during the past few years, as many as half of all children in a community report a history of low back pain. The current results, in accordance with previous findings, indicate that there is a subgroup of adolescents with more chronic symptoms which, in the authors' opinion, deserves more attention. Disc disease accompanying low back pain is a key issue both in research and clinical practice. The significance of early degenerative findings in the lumbar discs is not known. METHODS: In the survey of 14-year-olds (n = 1503), a subgroup (7.8%) with recurrent low back pain was found. A random sample of individuals with recurrent low back pain (n = 40) and an equal number of completely asymptomatic control subjects were selected for a comparative study. The selected groups were examined by magnetic resonance imaging at 15 and 18 years of age. The participation rate of youth at 14, 18, and 23 years of age for all three questionnaires was 82% (29 boys and 33 girls). Imaging data were interpreted by two blinded radiologists experienced in low-field-strength magnetic resonance imaging. In calculations of relative risks, the participants reporting recurrent low back pain in all phases of the study were compared with participants who had no persistently recurrent pain. RESULTS: Eleven participants (35%) in the original group with low back pain persistently reported recurrent pain. In 15-year-old participants with disc degeneration, the relative risk of reporting recurrent low back pain up to the age of 23 years was 16 (95% confidence interval 2.2-118) compared with those having no disc degeneration. In addition, disc protrusion and Scheuermann-type changes at 15 years contributed to the risk of persistently recurrent low back pain. CONCLUSIONS: The authors' earlier findings already favored the hypothesis of a causal relation between the early evolution of a degenerative process of lower lumbar discs and recurrent low back pain in the near future. The current results further strengthen this hypothesis, indicating that individuals with disc degeneration soon after the phase of rapid physical growth not only have an increased risk of recurrent low back pain at this age, but also a long-term risk of recurrent pain up to early adulthood.

Non-specific low back pain in children and adolescents: risk factors.

Low back pain (LBP) among children and adolescents has become the subject of an increasing amount of literature over the last 15 years. This topic, which was considered almost insignificant less than two decades ago, was the focus of a recent international meeting organised in Grenoble (France) in March 1999. This review paper is the result of an literature update search performed by members of three groups which have been active in this field for many years. Current epidemiological data on LBP is summarized as well as the role of the major risk factors according to studies published in the principal peer reviewed journals interested in the topic.

Back extensor and psoas muscle cross-sectional area, prior physical training, and trunk muscle strength--a longitudinal study in adolescent girls.

The association between physical training, low back extensor (erector spinae plus multifidus muscles) and psoas muscle cross-sectional areas (CSA) and strength characteristics of trunk extension and flexion were studied in adolescent girls. A group of athletes (n = 49) (age range 13.7-16.3 years) consisting of gymnasts, figure skaters and ballet dancers was age-matched with non-athletes (n = 17) who acted as a sedentary control group. The CSA of psoas muscles and multifidus plus erector spinae muscles were measured from lumbar axial images by magnetic resonance imaging. Maximal trunk extension and flexion forces were measured in a standing position using a dynamometer and trunk musculature endurance was evaluated using static holding tests. When CSA were adjusted with body mass, the athletes showed significantly greater CSA in both muscles studied (psoas P < 0.001; erector spinae plus multifidus P < 0.05) than the non-athletes. The athletes also had a greater absolute psoas muscle CSA (P < 0.01) and trunk flexion force (P < 0.01) compared to the controls. When the forces were expressed relative to body mass, the athletes were superior both in trunk flexion (P < 0.001) and extension (P < 0.001). There was a significant correlation between muscle CSA and strength parameters, but the force per muscle CSA did not differ significantly between the athletes and the non-athletes. In addition, the athletes showed a better body mass adjusted muscle endurance in trunk flexion (P < 0.05) than the non-athletes. Our study indicated that regular physical training enhances trunk musculature hypertrophy, force and endurance in adolescent girls, and that there is an association between muscle CSA and strength parameters.

Non-specific musculoskeletal pain in preadolescents. Prevalence and 1-year persistence.

A 1-year follow-up study of 1756 third- and fifth-grade schoolchildren was conducted with a structured pain questionnaire to assess the prevalence and persistence of self-reported musculoskeletal pain symptoms and disability caused by pain. At follow-up, 1626 (92.7%) children participated in the study. Pain at least once a week persisted in 270 (52.4%) of the 564 children who reported musculoskeletal pain at least once a week in at least one part of the body at baseline. Of the regional pain symptoms, neck pain had highest persistence and, in girls, significantly more than in boys. Persistence of pain was not related to school grade. Widespread pain, determined as in the criteria for fibromyalgia, was found in 132 children (7.5%) and persisted in 35 children (29.7%, 95% CI 21.9-38.4) at follow-up. Disability was more severe in children with pain symptoms in more than one area. This study showed that about half of the preadolescents complaining of musculoskeletal pain at least once a week at baseline had persistent pain symptoms at follow-up. The prognosis of widespread pain in preadolescents was almost the same as the previous findings in adults.

Psychiatric symptoms in preadolescents with musculoskeletal pain and fibromyalgia.

OBJECTIVES: To study the association of musculoskeletal pain with emotional and behavioral problems, especially depressive symptoms in Finnish preadolescents. STUDY DESIGN: A structured pain questionnaire was completed by 1756 third- and fifth-grade schoolchildren for identifying children with widespread pain (WSP), children with neck pain (NP), and pain-free controls for the comparative study. There were 124 children with WSP (mean age, 10.7 years), 108 children with NP (mean age, 11.1 years), and 131 controls (mean age, 10.7 years) who completed the Children's Depression Inventory (CDI) and a sleep questionnaire. A blinded clinical examination was done to detect fibromyalgia. For parental evaluation, the Child Behavior Checklist and a sociodemographic questionnaire were used. For teacher evaluation the Teacher Report Form was used. RESULTS: Children with WSP had significantly higher total emotional and behavioral scores than controls, according to child and parent evaluation. A significant difference in the mean total CDI scores was also found between the WSP and NP groups. Children with fibromyalgia had significantly higher CDI scores than the other children with WSP. CONCLUSIONS: Musculoskeletal pain, especially fibromyalgia, and depressive symptoms had high comorbidity. Pain and depressive symptoms should be recognized to prevent a chronic pain problem.

The prevalence of low back pain among children and adolescents. A nationwide, cohort-based questionnaire survey in Finland.

STUDY DESIGN: A nationwide, cohort-based cross-sectional questionnaire survey as a part of a population study. OBJECTIVES: To evaluate the prevalence of low back pain among Finnish children and adolescents. SUMMARY OF BACKGROUND DATA: Low back pain is common already in adolescence, but the results concerning sex differences and peak age of the prevalence have been partly controversial. Also, previous studies have been limited to smaller geographic areas. METHODS: The subjects were 594 girls and 577 boys, a total of 1171 children and adolescents. They were pupils of 45 different public schools. Various areas of Finland were included in the sampling process to represent different parts of the country and different living conditions. The subjects completed a validated questionnaire by themselves or with the help of a parent or guardian. The questionnaire was checked by a supervisor when entering the field study. The questionnaire included items that investigated the subjects' past and current low back pain. Low back pain was classified on the basis of timing, duration, and location. Subjects reporting pain in the low back area that interfered with school work or leisure activities during the previous 12 months were defined as having low back pain. RESULTS: The prevalence of back pain was low (1%) among the 7-year-old and 10-year-old (6%) schoolchildren, but increased with age, being 18% both among 14- and 16-year-old adolescents. No gender difference was found. Recurrent or chronic pain was reported by 26% of the boys and 33% of the girls who reported low back pain, and the proportion of recurrent and chronic pains of all low back pain incidents increased with age. CONCLUSIONS: Low back pain is a relatively common complaint at adolescence. In addition, a significant part of the pains are recurrent or chronic already with 14-year-old adolescents.

Lumbar mobility and low back pain during adolescence. A longitudinal three-year follow-up study in athletes and controls.

In this 3-year longitudinal study, we studied lumbar mobility and the occurrence of low back pain among 98 adolescents who were free of previous severe low back pain: 33 nonathletes (16 boys, 17 girls), 34 boy athletes (ice hockey and soccer players) and 31 girl athletes (figure skaters and gymnasts). During the followup, low back pain lasting longer than 1 week was reported by 29 athletes (15 boys and 14 girls) and by 6 nonathletes (3 boys and 3 girls). In multivariate analyses, participation in sports and low maximal lumbar flexion at the baseline predicted low back pain during the followup among boys; however, these factors accounted for only 16% of the variability between the groups with and without low back pain. Among girls, decreased range of motion in the lower lumbar segments, low maximal lumbar extension, and high body weight at the baseline were predictive of low back pain during the followup, accounting for 31% of the variability between the groups. The girls in the lowest tertile of maximal lumbar extension at baseline had a relative risk of 3.4 to have future low back pain compared with those in the highest tertile. We conclude that the low individual physiologic maximum of lower segment lumbar extension mobility may cause overloading of the low back among athletes involved in sports with frequent maximal lumbar extension and that it predicts future low back pain.

Training does not increase maximal lumbar extension in healthy adolescents.

OBJECTIVE: To investigate if there is training reserve in the maximal lumbar extension. DESIGN: Three-year longitudinal study. BACKGROUND: Among adults there is variation in the normal range of sagittal motion of the lumbar spine, but reduced spinal flexibility does not predict future occupational back pain. In various sports and in ballet, maximal extension of lumbar spine is a common manoeuvre, and low-back pain is also common. It is not known whether training increases maximal extension of healthy back. Forceful training of maximal extension may injure the anatomical structures limiting the extension range. METHODS: We compared lumbar sagittal flexibility to hip flexor and hamstring flexibility in a 3-year longitudinal study on female ballet dancers (n = 18), athletes (n = 31), and controls (n = 17) before and after their adolescent growth spurt. RESULTS: Ballet dancers had more flexible hamstrings and hip flexors than controls, but there were no group differences regarding the maximal lumbar flexion or extension. These results persisted throughout follow-up. CONCLUSIONS: The maximal physiological extension of the lumbar spine cannot be increased by training in healthy adolescents. RELEVANCE: An attempt to exceed the physiological maximum extension may only cause overly hard strain on specific anatomical structures of the lumbar spine. This knowledge should be considered when the rules of sports and choreography of dance performances are considered.

Joint hypermobility is not a contributing factor to musculoskeletal pain in pre-adolescents.

OBJECTIVE: To study the prevalence of joint hypermobility and the association of hypermobility with musculoskeletal pain in pre-adolescents. METHODS: Finnish school children in the 3rd and 5th grade, n = 1637, mean ages 9.8 and 11.8 years, were studied by Beighton criteria for joint hypermobility, with total score > or = 6 as a cutoff point for hypermobility, pretested questionnaire for musculoskeletal pain, and classification to different pain groups on the basis of painful body area and frequency of pain. RESULTS: The mean Beighton scores were 2.7 and 2.4 for the 3rd and 5th grade children, respectively. Total score was > or = 6 in 7.8% of the children. No association of hypermobility with musculoskeletal pain was found. Of the hypermobile children, 29.9% (95% CI 22.3 to 38.8), and of the nonhypermobile children, 32.3% (95% CI 29.9 to 34.7) had musculoskeletal pain at least once a week. Children with hypermobility did not have more pain due to injuries. Disability caused by musculoskeletal pain did not correlate with Beighton total score. CONCLUSION: Both joint hypermobility and musculoskeletal pain are common in pre-adolescents. Hypermobility appears not to be a contributing factor to musculoskeletal pain in pre-adolescents.

A video-based method for evaluation of low-back load in long-cycle jobs.

A method for evaluation of the physical load on the lumbar spine in industrial work is presented. It is suitable for identification of high spinal loads and their time duration. The method is based on biomechanical analysis of video-recordings. It takes into account the posture of the body as such, as well as the possible occurrence of external load and support. Compression of the L5-S1 intervertebral disc and strain on the lumbodorsal fascia is determined at 5-s intervals in each work task.

Low-back pain in adolescent athletes.

In this 3-yr longitudinal study we investigated the occurrence of low-back pain and anatomic changes in the low back in relation to loading and injuries among 98 adolescents: 33 nonathletes (16 boys, 17 girls), 34 boy athletes (17 ice hockey, 17 soccer players), and 31 girl athletes (17 figure skaters, 14 gymnasts). During the 3-yr follow-up, low-back pain lasting longer than 1 wk was reported by 29 (45%; 95% CI, 32%-57%) athletes and by 6 (18%; 95% CI, 7%-35%) nonathletes (P = 0.0099). Acute back injury was reported by 17 of 19 subjects who also reported low-back pain (89%; 95% CI, 67%-99%) and by 2 of 63 of those without prolonged low-back pain (3%; 95% CI, 0%-11%) (P < 0.0001). Among 43 girls participating in baseline and follow-up MRI examinations of the lumbar spine, new MRI abnormalities were found in 6 of 8 reporting acute back injury (75%; 95% CI, 35%-97%) and in 8 of the remaining 35 girls (23%; 95% CI 10% to 40%) (P = 0.018). In conclusion, excessive loading that involves a risk for acute low-back injuries during the growth spurt is harmful to the lower back.

Low back pain in the young. A prospective three-year follow-up study of subjects with and without low back pain.

STUDY DESIGN: This was a prospective 3-year follow-up study of randomized matched subgroups of 15-year-old school children with or without low back pain initially. OBJECTIVE: In addition to low back pain and leisure time physical activity, spinal mobility, trunk muscle strength, and early degenerative findings of the lumbar spine were evaluated. SUMMARY OF BACKGROUND DATA: Reliable epidemiologic studies on the prevalence of low back pain and development of early degenerative changes of the lumbar spine in young persons have been sparse. Along with several other characteristics, the relationship of these changes to frequent low back pain in young persons is not known. METHODS: After a questionnaire-based survey was administered, subjects with or without low back pain were examined initially and at follow-up with special reference to leisure time physical activity, anthropometry, spinal mobility, trunk muscle strength, and magnetic resonance imaging findings of the lumbar spine. RESULTS: At baseline and at follow-up, those subjects with initial low back pain were characterized by a low frequency of physical activity and decreased spinal function. During follow-up, the occurrence of disc degeneration increased significantly more in the original group with low back pain than among asymptomatic subjects. Furthermore, disc degeneration at baseline significantly predicted future frequent low back pain. Initial disc protrusion also predicted future frequent low back pain. CONCLUSION: After the rapid physical growth period, there seemed to be a causal relationship between the early evolution of the degenerative processes of the lower lumbar discs and frequent low back pain in several subjects.

Development of degenerative changes in the lumbar intervertebral disk: results of a prospective MR imaging study in adolescents with and without low-back pain.

PURPOSE: To investigate the frequency, pattern, and sequence of early degenerative changes in the lumbar spine. MATERIALS AND METHODS: On the basis of a survey of 1,503 14-year-old schoolchildren, a randomized sample of 40 subjects with low-back pain (LBP) and 40 asymptomatic subjects were invited to undergo magnetic resonance (MR) imaging of the lumbar spine at 15 and at 18 years of age. Altogether, 62 subjects participated in both studies. RESULTS: The frequency of disk degeneration at follow-up was greater in the patients with LBP (increased from 42% to 58%) than among the asymptomatic subjects (from 19% to 26%) (P = .01). No such difference was found with disk protrusion, although disk protrusion was seen only in subjects with LBP at baseline examination (19%). CONCLUSION: Degenerative changes emerge rapidly after the adolescent growth spurt. The MR imaging appearance of the degenerative processes is similar regardless of symptoms, although these processes are more common in symptomatic adolescents and develop at an earlier age. There appears to be a positive correlation between degenerative lumbar disk disease and LBP in adolescence.