Correction of leg-length discrepancy among meat cutters with low back pain: a randomized controlled trial.

BACKGROUND: The etiology of non-specific low back pain (LBP) is complex and not well understood. LBP is common and causes a remarkable health burden worldwide. Leg-length discrepancy (LLD) is potentially a risk factor for development of LBP, although this relationship has been questioned. Yet only one randomized controlled study (RCT) has been performed. The objective of our study was to evaluate the effect of insoles with leg-length discrepancy (LLD) correction compared to insoles without LLD correction among meat cutters in a RCT-design. METHODS: The study population consisted 387 meat cutters who were over 35 years old and had been working 10 years or more. The LLD measurement was done by a laser ultrasound technique. All workers with an LLD of at least 5 mm and an LBP intensity of at least 2 on a 10-cm Visual Analog Scale were eligible. The LLD of all the participants in the intervention group was corrected 70%, which means that if the LLD was for example 10 mm the correction was 7 mm. The insoles were used at work for eight hours per day. The control group had insoles without LLD correction. The primary outcome was between-group difference in LBP intensity. Secondary outcomes included sciatic pain intensity, disability (Roland Morris), RAND-36, the Oswestry Disability Index, physician visits and days on sick leave over the first year. We used a repeated measures regression analysis with adjustments for age, gender and BMI. The hurdle model was used for days on sick leave. RESULTS: In all, 169 workers were invited and 114 (67%) responded. Of them, 42 were eligible and were randomized to the intervention (n = 20) or control group (n = 22). The workers in the intervention group had a higher improvement in LBP intensity (- 2.6; 95% confidence intervals - 3.7 - - 1.4), intensity of sciatic pain (- 2.3; - 3.4 - - 1.07) and RAND-36 physical functioning (9.6; 1.6-17.6) and a lesser likelihood of sick leaves (OR -3.7; - 7.2 - -0.2). CONCLUSIONS: Correction of LLD with insoles was an effective intervention among workers with LBP and a standing job. TRIAL REGISTRATION: ISRCTN11898558 . Registration date 11. Feb 2011. BioMed Central Ltd.

Leg-length discrepancy is associated with low back pain among those who must stand while working.

BACKGROUND: Some studies suggest that leg length discrepancy (LLD) is associated with low back pain (LBP) but many have not found such an association leading to conflicting evidence on the role of LLD in LBP. METHODS: The study population consisted of meat cutters with a standing job and customer service workers with a sedentary job from Atria Suomi Ltd (Nurmo, Finland) who were at least 35 years old and had been working in their jobs for at least 10 years. Leg length of each participant was measured with a laser range meter fixed in a rod, which was holding the scanning head of the ultrasound apparatus. Association of the intensity of LBP (10-cm Visual Analog Scale) with LLD was analysed by linear regression model, while the hurdle model was used in analysing the association of number of days with LBP and days on sick leave during the past year. Associations were adjusted by gender, age, BMI, smoking, depressive feelings and type of work (standing or sedentary job). RESULTS: The final study population consisted of 114 meat cutters (26 females and 88 males) and 34 customer service workers (30 females and four males). Forty-nine percent of the meat cutters and 44% of the customer service workers had LLD of at least 6 mm, while 16% and 15%, respectively, had LLD of at least 11 mm. In the whole study population, LLD of 6 mm or more was associated with higher intensity of LBP and number of days with LBP. In the stratified analysis, both intensity of LBP and number of days of LBP were associated with LLD among meat cutters but not among customer service workers. The sick leaves during past year were slightly longer among those with LLD 10 mm or more, but the differences were not statistically significant. CONCLUSIONS: LLD, measured with a laser range meter, was associated with intensity of LBP and self-reported days with LBP during the past year among meat cutters engaged in standing work. TRIAL REGISTRATION: ISRCTN11898558--The role of leg length discrepancy in low back pain.

A replication study on proposed candidate genes in Ménière's disease, and a review of the current status of genetic studies.

OBJECTIVE: Multiple candidate genes have been presented for Ménière's disease (MD), but to date no positive replications have been reported. We review here all the previously proposed candidate genes for MD and report our results on the analysis of six such genes, AQP2, KCNE1, KCNE3, HCFC1, COCH, and ADD1. STUDY SAMPLE: A well-defined sample set of 38 sporadic and 21 familial Finnish MD patients. DESIGN: Mutation analysis, case-control study, and review of literature. RESULTS: A polymorphism rs1805127 in the potassium channel gene, KCNE1, was associated with MD in sporadic (p = 0.011), but not familial patients (p = 0.62). In addition, we identified four novel unique variations in the KCNE1 gene. PolyPhen and Mutation Taster analyses indicated that at least one of the variations c.259T > C; p.Trp87Arg is probably damaging to the coded protein. CONCLUSIONS: Our review of the reported candidate genes shows that the current understanding of the genetic factors contributing to the development of MD is limited, and that the study of its etiology would benefit greatly from more comprehensive genetic knowledge.

Sports, smoking, and overweight during adolescence as predictors of sciatica in adulthood: a 28-year follow-up study of a birth cohort.

Lifestyle factors such as smoking, obesity, and level of physical activity predict low back pain (LBP) and sciatica. The authors investigated whether participating in sports, smoking, and being overweight or obese at 14 years of age predicted hospitalizations due to LBP or sciatica in adulthood. In 1980, at the age of 14 years, a total of 11,399 members of the 1966 Northern Finland Birth Cohort returned the postal questionnaire. Patients from the 1966 Northern Finland Birth Cohort who were hospitalized because of LBP or sciatica were followed to the end of 2008 through the Finnish Hospital Discharge Register. Data were analyzed using Cox's proportional hazards multistate model with the Markov clock forward time scale. During follow-up, 119 females (2.7%) and 254 males (5.6%) had been hospitalized at least once because of LBP or sciatica. Among females, overweight was associated with an increased risk of second-time hospitalization for surgical treatment for sciatica (hazard ratio = 7.1, 95% confidence interval: 1.5, 34.4). Among males, smoking was associated with an increased risk of first-time nonsurgical hospitalization (hazard ratio = 1.8, 95% confidence interval: 1.2, 2.7) and second-time surgical hospitalization (hazard ratio = 3.2, 95% confidence interval: 1.2, 8.2). The authors found potentially modifiable risk factors in adolescence that predicted hospital treatments for low back disorders during adolescence and young adulthood.

Genetic susceptibility of intervertebral disc degeneration among young Finnish adults.

BACKGROUND: Disc degeneration (DD) is a common condition that progresses with aging. Although the events leading to DD are not well understood, a significant genetic influence has been found. This study was undertaken to assess the association between relevant candidate gene polymorphisms and moderate DD in a well-defined and characterized cohort of young adults. Focusing on young age can be valuable in determining genetic predisposition to DD. METHODS: We investigated the associations of existing candidate genes for DD among 538 young adults with a mean age of 19 belonging to the 1986 Northern Finland Birth Cohort. Nineteen single nucleotide polymorphisms (SNP) in 16 genes were genotyped. We evaluated lumbar DD using the modified Pfirrmann classification and a 1.5-T magnetic resonance scanner for imaging. RESULTS: Of the 538 individuals studied, 46% had no degeneration, while 54% had DD and 51% of these had moderate DD. The risk of DD was significantly higher in subjects with an allele G of IL6 SNPs rs1800795 (OR 1.45, 95% CI 1.07-1.96) and rs1800797 (OR 1.37, 95% CI 1.02-1.85) in the additive inheritance model. The role of IL6 was further supported by the haplotype analysis, which resulted in an association between the GGG haplotype (SNPs rs1800797, rs1800796 and rs1800795) and DD with an OR of 1.51 (95% CI 1.11-2.04). In addition, we observed an association between DD and two other polymorphisms, SKT rs16924573 (OR 0.27 95% CI 0.07-0.96) and CILP rs2073711 in women (OR 2.04, 95% CI 1.07-3.89). CONCLUSION: Our results indicate that IL6, SKT and CILP are involved in the etiology of DD among young adults.

Work Disability among Employees with Diabetes: Latent Class Analysis of Risk Factors in Three Prospective Cohort Studies.

BACKGROUND: Studies of work disability in diabetes have examined diabetes as a homogeneous disease. We sought to identify subgroups among persons with diabetes based on potential risk factors for work disability. METHODS: Participants were 2,445 employees with diabetes from three prospective cohorts (the Finnish Public Sector study, the GAZEL study, and the Whitehall II study). Work disability was ascertained via linkage to registers of sickness absence and disability pensions during a follow-up of 4 years. Study-specific latent class analysis was used to identify subgroups according to prevalent comorbid disease and health-risk behaviours. Study-specific associations with work disability at follow-up were pooled using fixed-effects meta-analysis. RESULTS: Separate latent class analyses for men and women in each cohort supported a two-class solution with one subgroup (total n = 1,086; 44.4%) having high prevalence of chronic somatic diseases, psychological symptoms, obesity, physical inactivity and abstinence from alcohol and the other subgroup (total n = 1,359; 55.6%) low prevalence of these factors. In the adjusted meta-analyses, participants in the 'high-risk' group had more work disability days (pooled rate ratio = 1.66, 95% CI 1.38-1.99) and more work disability episodes (pooled rate ratio = 1.33, 95% CI 1.21-1.46). These associations were similar in men and women, younger and older participants, and across occupational groups. CONCLUSIONS: Diabetes is not a homogeneous disease in terms of work disability risk. Approximately half of people with diabetes are assigned to a subgroup characterised by clustering of comorbid health conditions, obesity, physical inactivity, abstinence of alcohol, and associated high risk of work disability; the other half to a subgroup characterised by a more favourable risk profile.

Role of environmental factors and history of low back pain in sciatica symptoms among Finnish adolescents.

STUDY DESIGN: Cross-sectional study in a subcohort of the 1986 Northern Finland Birth Cohort (n = 1987). OBJECTIVE: To investigate the role of environmental factors and LBP history in sciatica symptoms among Finnish young adults. SUMMARY OF BACKGROUND DATA: History of low back pain (LBP), smoking, and male sex are associated with sciatica in adult populations. The role of the environmental determinants of sciatica has not been evaluated in populations consisting of only adolescents. METHODS: Sciatic symptoms and environmental exposures were elicited by a mailed questionnaire and the associations were analyzed using multinomial logistic regression. RESULTS: Female sex was associated with severe sciatica at 18 years (OR, 3.9; 95% confidence interval (CI), 1.6-9.3). Both reported LBP at 16 years and LBP requiring consultation of a health care professional were associated with mild sciatica at 18 years (OR, 2.5; 95% CI, 1.3-4.9; and OR, 3.8; 95% CI, 1.2-11.9). In addition, LBP at 16 years requiring consultation of a health care professional was associated with severe sciatica at 18 years (OR, 5.0; 95% CI, 1.7-15.3). Smoking, obesity, physical workload, and level of physical activity were not associated with sciatica. CONCLUSION: Females reported sciatic pain more often than males. LBP at 16 years predicted sciatica at 18 years. LEVEL OF EVIDENCE: 2.

Gender difference in genetic association between IL1A variant and early lumbar disc degeneration: a three-year follow-up.

OBJECTIVE: The purpose of the present study was to analyze the associations between specific genetic markers and early disc degeneration (DD) or early disc degeneration progression (DDP) defined by magnetic resonance imaging (MRI). METHODS: We selected eleven of the most promising single nucleotide polymorphisms (SNP) and compared the distributions of these genetic markers between groups defined by MRI in a Danish adolescent population (N=166) over a three-year follow-up period. RESULTS: We observed a ten-fold higher annual incidence of endplate changes than previously reported in adults. The gender difference in IL1A rs1800587 association with DD remained significant and another association with DDP emerged in follow-up assessment. Among girls, the rs1800587 T-allele was associated both with DD (OR 2.82 [95% CI 1.29-6.16]) and with DDP (OR 2.45 [95% CI 1.03-5.82]). Among boys, the IL6 rs1800795 genotype G/C was protective in both DD (OR 0.26 [95% CI 0.09-0.72]) and DDP (OR 0.32 [95% CI 0.12-0.88]) with the IL6 rs1800797 genotype G/A was associated with a decreased likelihood of DD (OR 0.27 [95% CI 0.10-0.77]). Gender-genotype interactions were significant for polymorphisms in both IL1A and IL6. Correction for multiple testing weakened the associations for IL6 polymorphisms. CONCLUSION: We conclude that gender specific effects in lumbar disc degeneration and its progression are possible. However, further evaluations in larger populations are needed. Our results provide some support to the hypothesis that early disc degeneration is an especially important phase in the cascade of degenerative disc disease.

Genetic risk factors of disc degeneration among 12-14-year-old Danish children: a population study.

The objective of the present study was to examine the associations between eleven putative predisposing single nucleotide polymorphisms (COL9A3, COL11A2, IL1A, IL1B, IL6 and VDR) and early disc degeneration (DD). The population consisted of 12 to 14-year-old Danish children (N=352). DD was evaluated from magnetic resonance images (MRI). We analysed the association between DD and single nucleotide polymorphisms or haplotypes using logistic regression analyses. Of the 352 children studied, 73 boys and 81 girls had no MRI changes, while 30 boys and 36 girls had lumbar DD. Among girls, IL1A rs1800587 in CT/TT compared to CC resulted in OR 2.85 [1.19-6.83]. In IL6 promoter polymorphism rs1800796, the C-allele was more frequent among the subjects with DD, OR 6.71 [1.71-26.3]. Of the IL6 haplotypes, GCG was associated with DD, OR 6.46 [1.61 - 26.0]. No associations were observed among boys. Our results suggest possible roles for IL1A and IL6 in early DD among girls.