Serum lipids in relation to sciatica among Finns

Modic Changes in the Lumbar Spine: Exploring Their Association with Abdominal Aortic Calcification as a Potential Indicator of Systemic Atherosclerosis

BACKGROUND

This was a cross-sectional study on the correlation between abdominal aortic calcification (AAC) and Modic changes (MC). Little is known regarding the etiology of MC in the lumbar spine. Currently, insufficient vascularization of the endplate has been proposed to contribute to the appearance of MC. Our objective was to investigate whether AAC, a marker for a poor vascular status, is associated with MC in patients suffering from degenerative disc disease.

METHODS

Radiologic images of patients (n = 130) suffering from degenerative lumbar disc disease were reviewed. Type and severity of MC were assessed using magnetic resonance images, and severity of AAC was evaluated using computed tomography images or fluoroscopy. Both items were dichotomized into minimal and relevant grades. The correlation between them was studied using Spearman's correlation test, with age as a covariate.

RESULTS

Of the patients, 113 (87%) demonstrated MC (31% type I, 63% type II, and 6% type III) (55% relevant grade), and 68% had AAC (44% relevant grade). Spearman statistical analysis revealed that AAC was correlated with age (P < 0.001), whereas MC were not (P = 0.142). AAC severity was significantly correlated with MC, remaining so after age adjustment (P < 0.05). While MC type I lacked correlation with AAC, MC type II were significantly correlated with AAC (0.288, P = 0.015); however, this association lost significance after adjusting for age (P = 0.057).

CONCLUSIONS

AAC and MC (mainly MC type II) are associated, indicating that reduced blood supply or even a poor systemic vascularization status due to atherosclerotic disease may play a role in the formation of MC. Future studies focusing on the etiology of MC should pay more attention to patients' vascular status and determinants of abdominal aorta calcification.

Causal associations between modifiable risk factors and intervertebral disc degeneration

BACKGROUND

Intervertebral disc degeneration (IVDD) is a common degenerative condition, which is thought to be a major cause of lower back pain (LBP). However, the etiology and pathophysiology of IVDD are not yet completely clear.

PURPOSE

To examine potential causal effects of modifiable risk factors on IVDD.

STUDY DESIGN

Bidirectional Mendelian randomization (MR) study.

PATIENT SAMPLE

Genome-wide association studies (GWAS) with sample sizes between 54,358 and 766,345 participants.

OUTCOME MEASURES

Outcomes included (1) modifiable risk factors associated with IVDD use in the forward MR; and (2) modifiable risk factors that were determined to have a causal association with IVDD in the reverse MR, including smoking, alcohol intake, standing height, education level, household income, sleeplessness, hypertension, hip osteoarthritis, HDL, triglycerides, apolipoprotein A-I, type 2 diabetes, fasting glucose, HbA1c, BMI and obesity trait.

METHODS

We obtained genetic variants associated with 33 exposure factors from genome-wide association studies. Summary statistics for IVDD were obtained from the FinnGen consortium. The risk factors of IVDD were analyzed by inverse variance weighting method, MR-Egger method, weighted median method, MR-PRESSO method and multivariate MR Method. Reverse Mendelian randomization analysis was performed on risk factors found to be caustically associated with IVDD in the forward Mendelian randomization analysis. The heterogeneity of instrumental variables was quantified using Cochran's Q statistic.

RESULTS

Genetic predisposition to smoking (OR=1.221, 95% CI: 1.068-1.396), alcohol intake (OR=1.208, 95% CI: 1.056-1.328) and standing height (OR=1.149, 95% CI: 1.072-1.231) were associated with increased risk of IVDD. In addition, education level (OR=0.573, 95%CI: 0.502-0.654)and household income (OR=0.614, 95%CI: 0.445-0.847) had a protective effect on IVDD. Sleeplessness (OR=1.799, 95%CI: 1.162-2.783), hypertension (OR=2.113, 95%CI: 1.132-3.944) and type 2 diabetes (OR=1.069, 95%CI: 1.024-1.115) are three important risk factors causally associated with the IVDD. In addition, we demonstrated that increased levels of triglycerides (OR=1.080, 95%CI:1.013-1.151), fasting glucose (OR=1.189, 95%CI:1.007-1.405), and HbA1c (OR=1.308, 95%CI:1.017-1.683) could significantly increase the odds of IVDD. Hip osteoarthritis, HDL, apolipoprotein A-I, BMI and obesity trait factors showed bidirectional causal associations with IVDD, therefore we considered the causal associations between these risk factors and IVDD to be uncertain.

CONCLUSIONS

This MR study provides evidence of complex causal associations between modifiable risk factors and IVDD. It is noteworthy that metabolic disturbances appear to have a more significant effect on IVDD than biomechanical alterations, as individuals with type 2 diabetes, elevated triglycerides, fasting glucose, and elevated HbA1c are at higher risk for IVDD, and the causal association of obesity-related characteristics with IVDD incidence is unclear. These findings provide new insights into potential therapeutic and prevention strategies. Further research is needed to clarify the mechanisms of these risk factors on IVDD.

Genetically predicted triglycerides mediate the relationship between type 2 diabetes Mellitus and intervertebral disc degeneration

BACKGROUND

To validate the causal relationship between type 2 diabetes mellitus (T2DM) and intervertebral disc degeneration (IVDD) and to identify and quantify the role of triglycerides (TGs) as potential mediators.

METHODS

A two-sample Mendelian randomization (MR) analyses of T2DM (61,714 cases and 1178 controls) and IVDD (20,001 cases and 164,682 controls) was performed using genome-wide association studies (GWAS). Moreover, two-step MR was employed to quantify the proportionate impact of TG-mediated T2DM on IVDD.

RESULTS

MR analysis showed that T2DM increased IVDD risk (OR: 1.0466, 95% CI 1.0049-1.0899, P = 0.0278). Reverse MR analyses demonstrated that IVDD does not affect T2DM risk (P = 0.1393). The proportion of T2DM mediated through TG was 11.4% (95% CI 5.5%-17.4%).

CONCLUSION

This work further validates the causality between T2DM and IVDD, with a part of the effect mediated by TG, but the greatest impacts of T2DM on IVDD remain unknown. Further studies are needed to identify other potential mediators.

Objective Evaluation of Chronic Low-Back Pain Using Serum Lipids: The Role of the Doctor-Patient Relationship

Statistical data show that pain intensity in patients with low back pain is associated with a higher BMI, total serum cholesterol, and triacylglycerol levels. The objective of our study was to evaluate how these associations are dependent on the nature of the patient-doctor relationship. Eighty-nine patients hospitalized with chronic low-back pain (50 women, 39 men; average age: 64.5 ± 12.7 years) were assessed over a 3-year period. A serum lipid analysis was conducted (LDL-C, HDL-C, and total cholesterols) at admission in parallel with a subjective evaluation of pain intensity, which was assessed using a numeric rating scale. The participating physician assigned, based on their personal interaction with the patient, an attribute of affinity (positive, neutral, and negative) towards them. Current serum lipid levels and pain intensity were correlated relative to these attributes. Pain intensity did not differ between the groups assigned positive or negative attributes of affinity. In patients belonging to the “positive” group, pain intensity correlated positively with total cholesterol ( $p=0.01$ ) and LDL cholesterol ( $p=0.007$ ). No correlations were found in the “negative” group or when the patient-doctor relationship was ignored. We found a significant association between subjectively assessed low back pain intensity and serum levels of total and LDL cholesterol in patients with whom the physician had a positive affinity. A positive affinity with the patients having chronic pain and the patient’s trust in their physicians may ultimately mean that the patient’s statement about pain is more credible, which may retroactively affect the outcome of therapy.

Impact of chronic hyperlipidemia on perioperative complications in patients undergoing lumbar fusion: a propensity score matching analysis

PURPOSE

Lumbar fusion is widely used to treat degenerative and traumatic conditions of the spine, with various perioperative complications. This study compared lumbar fusion complications in patients with and without chronic hyperlipidemia.

METHODS

Using the MSpine division of the PearlDiver database, patients with or without chronic hyperlipidemia who underwent lumbar fusions were identified. The appropriate Current Procedural Terminology (CPT) codes identified patients with single- or multi-level lumbar spinal fusion surgeries. International Classification of Diseases (ICD-9 and ICD-10) codes identified patients with chronic hyperlipidemia. The surgical and medical complications were obtained utilizing the appropriate ICD-9, ICD-10, and CPT codes. Propensity score matching analysis was used to control for confounding factors. Chi-square test was applied to compare the incidence of complications among different groups.

RESULTS

In single-level fusion group, patients with hyperlipidemia had a higher incidence of wound complications (P < 0.001), surgical site infection (P < 0.001), failed back syndrome (P < 0.001), hardware removal (P < 0.001), deep venous thrombosis/pulmonary embolism (P = 0.031), myocardial infarction (P < 0.001) cerebrovascular accident (P < 0.001), renal failure (P < 0.001), sepsis (P < 0.001), and urinary tract infection/incontinence (P < 0.001). In multi-level fusion group, patients with hyperlipidemia had a higher incidence of nerve root injury (P = 0.034), wound complications (P < 0.001), surgical site infection (P < 0.001), failed back syndrome (P < 0.001), hardware removal (P < 0.001), revision (P = 0.002), myocardial infarction (P < 0.001), renal failure (P < 0.001), and urinary tract infection/incontinence (P < 0.001).

CONCLUSION

Following lumbar fusion, patients with chronic hyperlipidemia have an increased risk of perioperative complications, including wound complications, surgical site infection, failed back surgery syndrome, hardware removal, myocardial infarction, renal failure, and urinary tract infection/incontinence.

Impact of dyslipidemia on the severity of symptomatic lumbar spine degeneration: A retrospective clinical study

BACKGROUND

Lumbar intervertebral disc degeneration (IVDD) is an important cause of low back pain or sciatica, and metabolic factors play an important role. However, little is known about the relationship of dyslipidemia to the risk of intervertebral disc degeneration (IVDD). This study aimed to assess the impact of serum lipid levels on the severity of lumbar disc degeneration and to investigate its association with endplate inflammation.

METHODS

We conducted a case retrospective study in which a total of 302 hospitalized Chinese patients were recruited, of whom 188 (112 males and 76 females; mean age: 51.66 years) were without underlying disease, while the remaining 114 patients (51 males and 63 females; mean age: 62.75 years) had underlying diseases. We examined fasting serum lipid levels for total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). Magnetic resonance imaging (MRI) was used to determine endplate inflammation. Pfirrmann grading and Weishaupt grading were used to evaluate the severity of intervertebral disc degeneration and facet joint degeneration, respectively.

RESULTS

There was no difference in age, gender, and general BMI between the two groups (P > 0.05), but there were significantly high levels in TC, LDL-C, and LDL-C/HDL-C (P = 0.04, P = 0.013, P = 0.01, respectively). TG and HDL-C showed no significant difference (P = 0.064, P = 0.336, respectively). The multivariate logistic regression model showed that age was a risk factor for the occurrence of endplate inflammation. In the group without underlying diseases, age, but not other indicators, was a risk factor for the occurrence of endplate inflammation (P < 0.01), In the group with underlying diseases, none of the patient indicators was directly related to the occurrence of endplate inflammation (P > 0.05). A nonlinear machine learning model was used to measure the contribution of each factor to the disease outcome and to analyze the effect between the top three contributing factors and the outcome variables. In patients without underlying diseases, the top three factors contributing to the severity grading of intervertebral disc degeneration were age (32.9%), high-density lipoproteins (20.7%), and triglycerides (11.8%). For the severity grading of facet joint degeneration, the top three contributing factors were age (27.7%), high-density lipoproteins (19.4%), and triglycerides (14.6%). For patients with underlying diseases, the top three factors contributing to intervertebral disc degeneration were age (25.4%), BMI (15.3%), and low-density lipoprotein/high-density lipoprotein ratio (13.9%). In terms of degree classification for facet joint degeneration, the top three contributing factors were age (17.5%), BMI (17.2%), and total cholesterol (16.7%).

CONCLUSION

This study shows that age, high-density lipoprotein, and triglycerides affect the degree of degeneration in patients with symptomatic lumbar degeneration without underlying diseases. Age and BMI are two major factors affecting the severity of degeneration in patients with underlying diseases, and dyslipidemia is a secondary factor. However, there is no clear association between dyslipidemia and the occurrence of endplate inflammation in either group.

Serum apolipoprotein B/apolipoprotein A1 ratio in relation to intervertebral disk herniation: a cross-sectional frequency-matched case-control study

Study design

This was a cross-sectional frequency-matched case–control study.

Background and aim

The serum lipid profile of lipoprotein(a) [Lp(a)] level and apolipoprotein B/apolipoprotein A1 ratio (Apo B/Apo A1) ratio were found to be more representative for serum lipid level and were recognized as the independent risk factors for various diseases. Although the blood levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were found to be associated with symptomatic intervertebral disk herniation (IDH), no studies to date have evaluated the association of Apo AI, Apo B, Lp(a), and Apo B/Apo AI levels with symptomatic IDH. This study aimed to assess the link between blood lipid levels and symptomatic IDH.

Method

The study included 1839 Chinese patients. Of these, 918 patients were diagnosed with IDH and enrolled in the experimental group. A control group of 921 patients underwent a physical examination during the same period. The serum lipid levels of TC, TG, LDL-C, HDL-C, Lp(a), Apo B, and Apo B/Apo AI were examined and analyzed. The control group comprised randomly selected patients who met the baseline levels of the aforementioned lipid molecules.

Results

Patients with IDH exhibited significantly higher TC, TG, LDL, Apo B, and Lp(a) levels than controls. The percentage of high TC, high TG, high LDL, high Apo B, and high Lp(a) were obviously higher in the IDH group than in the control group. However, hyperlipidemia had no relationship with the degenerated segment of the IDH (P = 0.201). The odds ratio (OR) for the incidence of IDH with elevated levels of LDL-C, TC, TG, Lp(a), Apo B, and Apo B/Apo AI was 1.583, 1.74, 1.62, 1.58, 1.49, and 1.39, respectively. The correlation analysis revealed the correlation between elevated LDL-C, TC, TG, Apo B, Lp(a), and incidence of IDH was significant (R²_LDL = 0.017; R²_TC = 0.004; R²_TG = 0.015; R²_{Apo B} = 0.004; R²_Lp(a) = 0.021) (P < 0.05).

Conclusion

This study suggested that elevated levels of serum TC, TG, LDL, Apo B, Lp(a), and Apo B/Apo AI were associated with a higher risk of IDH. This study provided useful information to identify a population that might be at risk of developing IDH based on elevated lipid levels.

Drp1-mediated mitochondrial fission is involved in oxidized low-density lipoprotein-induced AF cella poptosis

This study aimed to assess the negative effect of oxidized low-density lipoprotein (oxLDL) on annulus fibrosus (AF) cells and decipher the mechanism of action of the process. After treating AF cells with various concentrations (0, 25, 50, 100, and 200 μg/mL) of oxLDL for 24 and 48 hours, their viability was evaluated using cell counting kit-8 and live/dead staining. The percentage of AF cell death was determined with Annexin V/propidium iodide apoptosis staining. The expression of proteins related to the mitochondrial apoptosis pathway was determined using Western blot. Additionally, mitochondrial membrane potential (MMP) and intracellular reactive oxygen species (ROS) were assessed with JC-1 staining and dichlorodihydrofluorescein diacetate ormitoSOX probes, respectively. Mitochondrial morphology was observed with a transmission electron microscope. After treatment with oxLDL, AF cell viability decreased, pro-apoptosis proteins (such as Bax, cleaved caspase-9, and cleaved caspase-3) increased, and anti-apoptosis proteins (Bcl-2) declined. Excessive ROS and diminished MMP were also detected during this process, as were enhanced mitochondrial fission and augmented Drp1 expression. Furthermore, knocking down the expression of Drp1 rescued oxLDL-induced AF cell death. Collectively, these results suggest that oxLDL induces AF cell death through a mitochondria-related pathway. Enhanced mitochondrial fission was involved in oxLDL-induced AF cell death. Targeting Drp1, a target for regulating the process of mitochondrial fission, may be a feasible strategy for preventing intervertebral disc degeneration in hyperlipidemia.

A Simple Scale for Screening Lower-Extremity Arterial Disease as a Possible Cause of Low Back Pain: a Cross-sectional Study Among 542 Subjects

BACKGROUND

Epidemiological, imaging, and anatomical studies suggest an association between proximal arterial atherosclerosis and development of low back pain (LBP).

OBJECTIVES

We aimed to define (1) the frequency and (2) factors associated with exercise-induced proximal ischemia (EIPI) in individuals with LBP and (3) develop a clinical screening scale.

DESIGN

Monocentric cross-sectional study.

PARTICIPANTS

All patients with history of ongoing LBP referred to our exercise investigation laboratory for exercise transcutaneous oximetry (ex-tcPO₂) between January 2011 and December 2017 (n = 542; mean age, 65.4 ± 10.9; 83.9% men).

MAIN MEASURES

EIPI was defined as a decrease from rest of oxygen pressure (DROP) below - 15 mmHg on the lumbar and/or buttock probes. Ex-tcPO₂ is a reliable validated tool for diagnosing EIPI in comparison with arteriography and computed tomography angiography. Ex-tcPO₂ was performed on a treadmill until symptom manifestation or exhaustion. Clinical data were collected using interview questionnaires, medical file review, and clinical examination.

KEY RESULTS

EIPI was diagnosed in 282 patients (52%). Age ≤ 70 years (OR, 2.22; 95% CI, 1.35-3.57; p = 0.002), a history of proximal revascularization (OR, 2.64; 95% CI, 1.50-4.65; p = 0.001), use of antiplatelet medication (OR, 1.71; 95% CI, 0.96-3.06; p = 0.069), a relationship between exercise and LBP (OR, 2.61; 95% CI, 1.49-4.57; p = 0.001), and an abnormal ankle to brachial index (OR, 2.87; 95% CI, 1.77-4.66; p < 0.0001) were identified as EIPI predictors. Using these items, we developed a screening scale that showed an area under the receiver operating characteristics curve of .756. At a score of ≥ 3, the sensitivity, specificity, and accuracy for EIPI were 84%, 55%, and 71%, respectively.

CONCLUSIONS

EIPI was common among our patients with LBP undergoing ex-TcPO₂. Our screening scale could help better select the patients who require angiography.

The impact and distinction of 'lipid healthy but obese' and 'lipid abnormal but not obese' phenotypes on lumbar disc degeneration in Chinese

Background

Lipid abnormality and obesity have been proposed to be associated with lumbar disc degeneration, but little is known about the effect of ‘lipid healthy but obese’ (LH-O) and ‘lipid abnormal but not obese’ (LA-NO) phenotypes on lumbar disc degeneration in Chinese. The study aims to determine the impact and distinction of LH-O and LA-NO phenotypes on lumbar disc degeneration in Chinese, and to identify the association of related factors with risk of lumbar disc degeneration.

Methods

A total of 678 individuals were included with lumbar magnetic resonance imaging, serum lipid levels and anthropometric measurements. Obesity was defined on the basis of body mass index or waist to hip ratio (WHR). Pfirrmann score and Weishaupt’s scale were utilized to assess the degree of disc degeneration and facet joint degeneration.

Results

The incidence of the LH-O and LA-NO phenotypes were 11.4% and 18.1%, respectively. LA-NO phenotype demonstrates a high incidence for disc degeneration (P < 0.05), while LH-O phenotype confers a severe disc degeneration grade (P < 0.05). No statistical difference in the percentage of severe facet joint degeneration grade in each group (P > 0.05). Elevated triglycerides and greater WHR may be the risk factors for lumbar disc degeneration in Chinese.

Conclusion

LH-O and LA-NO phenotypes are common with different status of disc degeneration in Chinese. Elevated triglycerides and abdominal obesity appear to play crucial roles in the development of lumbar disc degeneration.

APOE-knockout in rabbits causes loss of cells in nucleus pulposus and enhances the levels of inflammatory catabolic cytokines damaging the intervertebral disc matrix

Rabbits with naturally high levels of cholesterol ester transfer protein (CETP), unlike rodents, have become an interesting animal model for the study of lipid metabolism and atherosclerosis, as they have similarities to humans in lipid metabolism, cardiovascular physiology and susceptibility to develop atherosclerosis. Rodents, such as mice, are not prone to atherosclerosis as they lack the mass and activity of CETP, as a key player in lipoprotein metabolism. Recently, APOE-knockout in rabbits has been shown to promote atherosclerosis and associated premature IVD degeneration that mimic the symptoms of atherosclerosis and structural changes of IVDs in humans. Here we examined whether APOE-knockout promoted IVD degeneration in rabbits is associated with imbalanced inflammatory catabolic activities, as the underlying problem of biological deterioration that mimic the symptoms of advanced IVD degeneration in humans. We analysed in lumbar nucleus pulposus (NP) of APOE-knockout rabbits the cell viabilities and the intracellular levels of inflammatory, catabolic, anti-catabolic and anabolic proteins derogating IVD matrix. Grades of IVD degeneration were evaluated by magnetic resonance imaging. NP cells were isolated from homozygous APOE-knockout and wild-type New Zealand White rabbits of similar age. Three-dimensional cell culture with low-glucose was completed in alginate hydrogel. Cell proliferation and intracellular levels of target proteins were examined by MTT and ELISA assays. Alike human NP cells of different disc degeneration grades, NP cells of APOE-knockout and wild-type rabbits showed significantly different in vivo cell population densities (p<0.0001) and similar in vitro proliferation rates. Furthermore, they showed differences in overexpression of selective inflammatory and catabolic proteins (p<0.0001) similar to those found in human NP cells of different disc degeneration grades, such as IL-1β, TNF-α, ADAMTS-4, ADAMTS-5 and MMP-3. This study showed that premature IVD degeneration in APOE-knockout rabbits was promoted by the accumulation of selective inflammatory catabolic factors that enhanced imbalances between catabolic and anabolic factors mimicking the symptoms of advanced IVD degeneration in humans. Thus, APOE-knockout rabbits could be used as a promising model for therapeutic approaches of degenerative disc disorders.

Obese Patients Benefit, but do not Fare as Well as Nonobese Patients, Following Lumbar Spondylolisthesis Surgery: An Analysis of the Quality Outcomes Database

BACKGROUND

Given recent differing findings following 2 randomized clinical trials on degenerative lumbar spondylolisthesis (DLS) surgery, there is a need to better define how subsets of patients fare following surgery.

OBJECTIVE

To investigate the impact of obesity on patient-reported outcomes (PROs) following DLS surgery.

METHODS

A total of 12 high-enrolling sites were queried, and we found 797 patients undergoing surgery for grade 1 DLS. For univariate comparisons, patients were stratified by BMI ≥ 30 kg/m2 (obese) and &lt; 30 kg/m2 (nonobese). Baseline, 3-mo, and 12-mo follow-up parameters were collected. PROs included the North American Spine Society satisfaction questionnaire, numeric rating scale (NRS) back pain, NRS leg pain, Oswestry Disability Index (ODI), and EuroQoL-5D (EQ-5D) Questionnaire.

RESULTS

We identified 382 obese (47.9%) and 415 nonobese patients (52.1%). At baseline, obese patients had worse NRS back pain, NRS leg pain, ODI, and EQ-5D scores (P &lt; .001, P = .01, P &lt; .001, and P = .02, respectively). Both cohorts improved significantly for back and leg pain, ODI, and EQ-5D at 12 mo (P &lt; .001). At 12 mo, similar proportions of obese and nonobese patients responded that surgery met their expectations (62.6% vs 67.4%, P = .24). In multivariate analyses, BMI was independently associated with worse NRS leg pain and EQ-5D at 12 mo (P = .01 and P &lt; .01, respectively) despite adjusting for baseline differences.

CONCLUSION

Obesity is associated with inferior leg pain and quality of life—but similar back pain, disability, and satisfaction—12 mo postoperatively. However, obese patients achieve significant improvements in all PRO metrics at 12 mo.

Trans-Ethnic Polygenic Analysis Supports Genetic Overlaps of Lumbar Disc Degeneration With Height, Body Mass Index, and Bone Mineral Density

Lumbar disc degeneration (LDD) is age-related break-down in the fibrocartilaginous joints between lumbar vertebrae. It is a major cause of low back pain and is conventionally assessed by magnetic resonance imaging (MRI). Like most other complex traits, LDD is likely polygenic and influenced by both genetic and environmental factors. However, genome-wide association studies (GWASs) of LDD have uncovered few susceptibility loci due to the limited sample size. Previous epidemiology studies of LDD also reported multiple heritable risk factors, including height, body mass index (BMI), bone mineral density (BMD), lipid levels, etc. Genetics can help elucidate causality between traits and suggest loci with pleiotropic effects. One such approach is polygenic score (PGS) which summarizes the effect of multiple variants by the summation of alleles weighted by estimated effects from GWAS. To investigate genetic overlaps of LDD and related heritable risk factors, we calculated the PGS of height, BMI, BMD and lipid levels in a Chinese population-based cohort with spine MRI examination and a Japanese case-control cohort of lumbar disc herniation (LDH) requiring surgery. Because most large-scale GWASs were done in European populations, PGS of corresponding traits were created using weights from European GWASs. We calibrated their prediction performance in independent Chinese samples, then tested associations with MRI-derived LDD scores and LDH affection status. The PGS of height, BMI, BMD and lipid levels were strongly associated with respective phenotypes in Chinese, but phenotype variances explained were lower than in Europeans which would reduce the power to detect genetic overlaps. Despite of this, the PGS of BMI and lumbar spine BMD were significantly associated with LDD scores; and the PGS of height was associated with the increased the liability of LDH. Furthermore, linkage disequilibrium score regression suggested that, osteoarthritis, another degenerative disorder that shares common features with LDD, also showed genetic correlations with height, BMI and BMD. The findings suggest a common key contribution of biomechanical stress to the pathogenesis of LDD and will direct the future search for pleiotropic genes.

Exposure to whole-body vibration and hospitalization due to lumbar disc herniation

Objective

The aim was to examine if exposure to whole-body vibration (WBV) increases the risk for hospitalization due to lumbar disc herniation.

Methods

The study basis is a cohort of 288,926 Swedish construction workers who participated in a national occupational health surveillance programme from 1971 until 1992. Job title, smoking habits, body weight, height and age were registered at the examinations. Assessment of WBV were made for each of the constituent occupations by constructing a job-exposure matrix (JEM). Exposure to WBV was graded on a scale from 0 to 5. In addition, the occurrence of hospitalization due to lumbar disc herniation from January 1st 1987 until December 31st 2010 was collected from a linkage with the Swedish Hospital Discharge Register. Poisson regressions were used to estimate relative risk with 95 percent confidence intervals (95% CI), adjusting for age, height, weight and smoking, using white-collar workers and foremen as a reference group.

Results

There was an increased risk for hospitalization due to lumbar disc herniation for workers in the construction industry exposed to medium to high WBV compared to white-collar workers and foremen 1.35 (1.12–1.63). When restricting the analyses to include workers 30–49 years of age at the time of the hospital admission the risk was 1.69 (95% CI 1.29–2.21).

Conclusion

This study further supports that occupational exposure to whole-body vibration increases the risk for hospitalization due to lumbar disc herniation.

Electronic supplementary material

The online version of this article (10.1007/s00420-018-1316-5) contains supplementary material, which is available to authorized users.

Lifestyle Risk Factors Increase the Risk of Hospitalization for Sciatica: Findings of Four Prospective Cohort Studies

BACKGROUND

The purpose of this study is to assess the effects of lifestyle risk factors on the risk of hospitalization for sciatica and to determine whether overweight or obesity modifies the effect of leisure-time physical activity on hospitalization for sciatica.

METHODS

We included 4 Finnish prospective cohort studies (Health 2000 Survey, Mobile Clinic Survey, Helsinki Health Study, and Young Finns Study) consisting of 34,589 participants and 1259 hospitalizations for sciatica during 12 to 30 years of follow-up. Sciatica was based on hospital discharge register data. We conducted a random-effects individual participant data meta-analysis.

RESULTS

After adjustment for confounding factors, current smoking at baseline increased the risk of subsequent hospitalization for sciatica by 33% (95% confidence interval [CI], 13%-56%), whereas past smokers were no longer at increased risk. Obesity defined by body mass index increased the risk of hospitalization for sciatica by 36% (95% CI 7%-74%), and abdominal obesity defined by waist circumference increased the risk by 41% (95% CI 3%-93%). Walking or cycling to work reduced the risk of hospitalization for sciatica by 33% (95% CI 4%-53%), and the effect was independent of body weight and other leisure activities, while other types of leisure activities did not have a statistically significant effect.

CONCLUSIONS

Smoking and obesity increase the risk of hospitalization for sciatica, whereas walking or cycling to work protects against hospitalization for sciatica. Walking and cycling can be recommended for the prevention of sciatica in the general population.

Knockout of Apolipoprotein E in rabbit promotes premature intervertebral disc degeneration: A new in vivo model for therapeutic approaches of spinal disc disorders

Intervertebral disc (IVD) degeneration that accelerates the loss of disc structural and functional integrities is recognized as one of the major factors of chronic back pain. Cardiovascular risk factors, such as deficits of apolipoproteins that elevate the levels of cholesterol and triglycerides, are considered critical for the progress of atherosclerosis; notably in the abdominal aorta and its lumbar branching arteries that supply lumbar vertebrae and IVDs. Obstruction of the lumbar arteries by atherosclerosis is presumed to promote lumbar disc degeneration and low back pain. APOE-knockout rabbits have recently been shown to generate hyperlipidemia with increased levels of cholesterol and triglycerides that mimic the symptoms of atherosclerosis in humans. Here, we analysed IVD degeneration in the lumbar spines of ten homozygous APOE-knockout and four wild-type New Zealand White rabbits of matching age to prove accelerated IVD degeneration in APOE-knockout rabbits, since APOE-knockout rabbits could be a beneficial model for therapeutic approaches of degenerative IVD disorders. Experiments were performed using T1/T2-weighted magnetic resonance imaging, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, glucose-oxidase assay, enzyme-linked immunosorbent assay, quantitative reverse transcription PCR and western blot. APOE-knockout lumbar spines showed more advanced IVD degeneration, obstructed lumbar arteries and lower enhancement of contrast agent in IVDs. Moreover, lower concentration of glucose, lower number of viable cells and lower concentrations of aggrecan, collagen II and higher concentration of collagen I were detected in APOE-knockout IVDs (p < 0.0001). APOE-knockout in rabbits could induce structurally deteriorating premature IVD degeneration that mimics the symptoms of accelerated IVD degeneration in humans. APOE-knockout rabbits could be used as beneficial model, as they can bypass the standard surgical interventions that are commonly applied in research animals for the induction of enhanced IVD degeneration. Their parallel use in therapeutic approaches of IVD disorders and atherosclerosis could reduce the number of research animals to be used and contribute to the principles of 3Rs (Replacement, Reduction and Refinement).

Is there a relationship between blood lipids and lumbar disc herniation in young Turkish adults?

INTRODUCTION

Atherosclerosis might diminish the nutrient supply to intervertebral discs (IVD), leading to disc herniation. Therefore, there is interest in determining the possible association between the blood lipid profile and lumbar disc herniation (LDH). We aimed to evaluate the association between blood lipids and LDH in a homogeneous group of patients, controlling for age- and sex-specific effects.

MATERIAL AND METHODS

This is a case-control study which consisted of 100 individuals (mean age: 41.25 ±9.09; 50 men and 50 women), classified into two groups, as follows. Group I (G-I) consisted of 50 patients who underwent surgery for symptomatic LDH, while group II (G-II) consisted of 50 patients with nonspecific complaints of a headache, but with no previous history of back and/or leg pain, recruited among patients admitted to the outpatient clinic at the time of the study, and whose age and sex were matched to the study group. Total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), fasting blood glucose, and hemoglobin A_1c levels were measured. The TC/HDL-C ratio was calculated. Blood pressure, waist circumference, body mass index, and the history of smoking were included in the analysis.

RESULTS

The mean values of the TC, TG, LDL-C, HDL-C levels and TC/HDL-C ratio were 198.38, 132.76, 131.9, 40.38 mg/dl and 5.09, respectively. No statistically significant relationship between the blood lipid profile and LDH was identified in this population.

CONCLUSIONS

Blood lipid levels in this young adult Turkish population did not predict LDH, and may not be a leading cause of IVD ischemia and IVD degeneration.

The Association Between Atherosclerosis and Low Back Pain: A Systematic Review

OBJECTIVE

To assess the evidence of association between atherosclerosis and low back pain (LBP). TYPE: Focused systematic review.

LITERATURE SURVEY

PubMed, Web of Science, CINAHL, and EMBASE were searched for original research articles, not limited by language, from January 1, 1990, to October 31, 2016.

METHODOLOGY

Titles and then abstracts were identified using predefined search terms and excluded based on lack of relevancy. This was followed by full-text reviews. Two authors independently assessed methodological quality based on Cochrane Handbook for Systematic Reviews of Interventions.

SYNTHESIS

A total of 26 studies met the inclusion criteria. The quality of the studies was low to moderate. There was significant heterogeneity across articles with respect to methodology. There was insufficient evidence to support an association between ischemia and low back pain.

CONCLUSIONS

The cause of LBP remains poorly understood. Better insight into how intervertebral disk changes relate to LBP is needed to guide future research. High-quality prospective studies are needed to answer the question of whether atherosclerosis is a risk factor for LBP.

LEVEL OF EVIDENCE

II.

Leisure-time physical activity and sciatica: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

The role of leisure-time physical activity in sciatica is uncertain. This study aimed to assess the association of leisure-time physical activity with lumbar radicular pain and sciatica.

DATABASES AND DATA TREATMENT

Literature searches were conducted in PubMed, Embase, Web of Science, Scopus, Google Scholar and ResearchGate databases from 1964 through August 2015. A random-effects meta-analysis was performed, and heterogeneity and small-study bias were assessed.

RESULTS

Ten cohort (N = 82,024 participants), four case-control (N = 9350) and four cross-sectional (N = 10,046) studies qualified for meta-analysis. In comparison with no regular physical activity, high level of physical activity (≥4 times/week) was inversely associated with new onset of lumbar radicular pain or sciatica in a meta-analysis of prospective cohort studies [risk ratio (RR) = 0.88, 95% CI 0.78-0.99, I²  = 0%, 7 studies, N = 78,065]. The association for moderate level of physical activity (1-3 times/week) was weaker (RR = 0.93, CI 0.82-1.05, I²  = 0%, 6 studies, N = 69,049), and there was no association with physical activity for at least once/week (RR = 0.99, CI 0.86-1.13, 9 studies, N = 73,008). In contrast, a meta-analysis of cross-sectional studies showed a higher prevalence of lumbar radicular pain or sciatica in participants who exercised at least once/week [prevalence ratio (PR) = 1.29, CI 1.09-1.53, I²  = 0%, 4 studies, N = 10,046], or 1-3 times/week (PR = 1.34, CI 1.02-1.77, I²  = 0%, N = 7631) than among inactive participants. There was no evidence of small-study bias.

CONCLUSIONS

This meta-analysis suggests that moderate to high level of leisure physical activity may have a moderate protective effect against development of lumbar radicular pain. However, a large reduction in risk (>30%) seems unlikely.

WHAT DOES THIS REVIEW ADD

Leisure-time physical activity may reduce the risk of developing lumbar radicular pain.

Serum lipid levels are positively correlated with lumbar disc herniation--a retrospective study of 790 Chinese patients

Background

Abnormal serum lipid levels have been shown to be associated with the occurrence of atherosclerosis, but little is known about the relationships of them with the risk of developing intervertebral disc degeneration (IVDD) in Chinese population.

Methods

We performed a case–control study to assess the relationship between serum lipid levels and lumbar disc degeneration. A total of 790 Chinese patients were recruited for this study at the time of hospitalization. We examined fasting serum lipid levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). 396 patients (235 men and 161 women; mean age: 41.07 years) underwent surgery for single-level lumbar disc herniation. A control group of 394 patients (225 men and 169 women; mean age: 42.1 years) underwent surgery for wounded lower limbs during the same period. Patients in the control group were collected randomly from among patients who were age- and sex-matched patients with the case group.

Results

Patients with lumbar disc herniation had significantly higher TC and LDL-C serum concentrations (P < 0.001 for both) than controls. Percentage of High-TC, High-TG, High-LDL-C, borderline High-TC and borderline High-LDL-C were significantly higher in the disc herniation group (P = 0.017, P = 0.002, P = 0.039, P =0.002 and P < 0.001, respectively). Ratios of TC/HDL-C and LDL-C/HDL-C were significantly associated with disc herniation (P < 0.001 for both). Logistic regression revealed that patients with higher serum LDL-C levels had a higher risk of disc herniation, in which odds ratio (OR) was 1.462 and confidence interval (CI) was 1.179 ~ 1.813. Moreover, patients with High-TG and borderline High-LDL-C had a higher probability of disc herniation (OR: 2.974, CI: 1.488 ~ 5.945, statistical power: 100 %; OR: 1.626, CI: 1.012 ~ 2.612, statistical power: 61.4 %, respectively). However, hyperlipidaemia did not seem to be associated with the herniated segment of the lumbar intervertebral disc (p = 0.374).

Conclusions

The present study suggests that dyslipidaemia may be associated with a higher risk of developing lumbar disc herniation. Serum lipid levels could be a useful predictor for intervertebral disc degeneration in Chinese population.

The Effect of Smoking on the Risk of Sciatica: A Meta-analysis

BACKGROUND

The role of smoking in sciatica is unknown. This study aimed to estimate the effect of smoking on lumbar radicular pain and clinically verified sciatica.

METHODS

Comprehensive literature searches were conducted in PubMed, Embase, Web of Science, Scopus, Google Scholar, and ResearchGate databases from 1964 through March 2015. We used a random-effects meta-analysis, assessed heterogeneity and publication bias, and performed sensitivity analyses with regard to study design, methodological quality of included studies, and publication bias.

RESULTS

Twenty-eight (7 cross-sectional [n = 20,111 participants], 8 case control [n = 10,815], and 13 cohort [n = 443,199]) studies qualified for a meta-analysis. Current smokers had an increased risk of lumbar radicular pain or clinically verified sciatica (pooled adjusted odds ratio [OR] 1.46; 95% confidence interval [CI], 1.30-1.64, n = 459,023). Former smokers had only slightly elevated risk compared with never smokers (pooled adjusted OR 1.15; 95% CI, 1.02-1.30, n = 387,196). For current smoking the pooled adjusted OR was 1.64 (95% CI, 1.24-2.16, n = 10,853) for lumbar radicular pain, 1.35 (95% CI, 1.09-1.68, n = 110,374) for clinically verified sciatica, and 1.45 (95% CI, 1.16-1.80, n = 337,796) for hospitalization or surgery due to a herniated lumbar disc or sciatica. The corresponding estimates for past smoking were 1.57 (95% CI, 0.98-2.52), 1.09 (95% CI, 1.00-1.19), and 1.10 (95% CI, 0.96-1.26). The associations did not differ between men and women, and they were independent of study design. Moreover, there was no evidence of publication bias, and the observed associations were not due to selection or detection bias, or confounding factors.

CONCLUSIONS

Smoking is a modest risk factor for lumbar radicular pain and clinically verified sciatica. Smoking cessation appears to reduce, but not entirely eliminate, the excess risk.

Body Mass Index and Risk for Clinical Lumbar Spinal Stenosis: A Cohort Study

STUDY DESIGN

A prospective cohort study that used a Swedish nationwide occupational surveillance program for construction workers (period of registration from 1971 to 1992). In all, 364,467 participants (mean age at baseline 34 yr) were included in the study.

OBJECTIVE

To determine whether overweight and obesity are associated with a higher risk of lumbar spinal stenosis (LSS).

SUMMARY OF BACKGROUND DATA

During recent decades, LSS has become the most common indication for spine surgery, a change that coincides with a higher prevalence of obesity.

METHODS

A diagnosis of LSS was collected through individual linkage to the Swedish National Patient Register through December 31, 2011. Poisson regression models were employed to estimate multivariable-adjusted incidence rate ratios (IRRs) for LSS.

RESULTS

At baseline, 65% had normal weight (BMI [body mass index]: 18.5-24.99 kg/m), 29% were overweight (BMI: 25-29.99 kg/m), 5% were obese (BMI ≥30 kg/m), and 2% were underweight (BMI <18.5 kg/m). During 11,190,944 person-years of follow-up, with a mean of 31 years, 2381 participants were diagnosed with LSS. Compared with normal weight individuals, obese workers had an IRR of 2.18 (95% confidence interval, 1.87-2.53) for LSS and overweight workers had an IRR of 1.68 (95% confidence interval, 1.54-1.83). Workers who were underweight halved their risk of LSS (IRR: 0.52, 95% confidence interval, 0.30-0.90).

CONCLUSION

Obese and overweight persons are at a higher risk of developing LSS. Furthermore, our results indicate that obesity might be a novel explanation for the increased number of patients with clinical LSS.

LEVEL OF EVIDENCE

3.

Physical activity is associated with elevated arterial stiffness in patients with lumbar disk herniation

STUDY DESIGN

A cross-sectional study in a general health examination.

OBJECTIVE

To investigate the relationship between brachial-ankle pulse wave velocity (baPWV) and lumbar disk herniation (LDH).

SUMMARY OF BACKGROUND DATA

Lumbar disk herniation (LDH) is a major cause of low back pain and sciatica. Various vascular risk factors such as obesity, diabetes mellitus, and smoking have been reported to be associated with LDH. BaPWV is an early indicator of subclinical atherosclerosis.

METHODS

A total of 490 participants with LDH and 490 participants without LDH were selected for the evaluation of baPWV. BaPWV was measured using an automatic device. The prevalence of LDH was calculated by the quartiles of baPWV levels. Multiple linear regression analysis was performed to evaluate the risk factors for baPWV.

RESULTS

LDH patients had significantly higher readings of baPWV compared with non-LDH subjects (P<0.001). The prevalence rate of LDH gradually increased according to baPWV quartiles. In addition, the levels of baPWV tended to increase as the frequency of physical activity reduced. Multiple linear regression analysis showed that body mass index, low-density lipoprotein cholesterol, physical activity, and systolic blood pressure contributed to increased baPWV.

CONCLUSIONS

The findings showed that LDH patients had higher baPWV levels. In addition, reduced physical activity was a risk factor contributing to increased baPWV. Further studies are warranted to determine the role of baPWV in LDH.

Do abnormal serum lipid levels increase the risk of chronic low back pain? The Nord-Trøndelag Health Study

Background

Cross-sectional studies suggest associations between abnormal lipid levels and prevalence of low back pain (LBP), but it is not known if there is any causal relationship.

Objective

The objective was to determine, in a population-based prospective cohort study, whether there is any relation between levels of total cholesterol, high density lipoprotein (HDL) cholesterol and triglycerides and the probability of experiencing subsequent chronic (LBP), both among individuals with and without LBP at baseline.

Methods

Information was collected in the community-based HUNT 2 (1995–1997) and HUNT 3 (2006–2008) surveys of an entire Norwegian county. Participants were 10,151 women and 8731 men aged 30–69 years, not affected by chronic LBP at baseline, and 3902 women and 2666 men with LBP at baseline. Eleven years later the participants indicated whether they currently suffered from chronic LBP.

Results

Among women without LBP at baseline, HDL cholesterol levels were inversely associated and triglyceride levels positively associated with the risk of chronic LBP at end of follow-up in analyses adjusted for age only. Adjustment for the baseline factors education, work status, physical activity, smoking, blood pressure and in particular BMI largely removed these associations (RR: 0.96, 95% CI: 0.85–1.07 per mmol/l of HDL cholesterol; RR: 1.16, 95% CI: 0.94–1.42 per unit of lg(triglycerides)). Total cholesterol levels showed no associations. In women with LBP at baseline and men without LBP at baseline weaker relationships were observed. In men with LBP at baseline, an inverse association with HDL cholesterol remained after complete adjustment (RR: 0.83, 95% CI: 0.72–0.95 per mmol/l).

Conclusion

Crude associations between lipid levels and risk of subsequent LBP in individuals without current LBP are mainly caused by confounding with body mass. However, an association with low HDL levels may still remain in men who are already affected and possibly experience a higher pain intensity.

The association between the history of cardiovascular diseases and chronic low back pain in South Koreans: a cross-sectional study

Background

Cardiovascular disease and related risk factors have been suggested as a mechanism leading to atherosclerosis of the lumbar vessels and consequent lumbar pain or sciatica. But there is continued controversy concerning its generalization. This study examined whether cardiovascular disease or its risk factors were associated with chronic low back pain (cLBP) in Koreans.

Methods

Health surveys and examinations were conducted on a nationally representative sample (n = 23,632) of Koreans. A total of 13,841 eligible participants (aged 20 to 89 years) were examined to determine the association between cardiovascular disease, the Framingham risk score, major cardiovascular risk factors (blood pressure, diabetes, cholesterol, and smoking habits) and chronic LBP.

Results

The total prevalence of cLBP was 16.6% (men: 10.8%, women: 21.1%) and that in patients with a history of cardiovascular diseases was 36.6% (men: 26.5%, women: 47.1%). The results showed that patients’ medical history of cardiovascular disease was significantly associated with cLBP in both men and women when adjusted for covariates (men: OR 2.16; 95%CI 1.34∼3.49; women: OR 2.26; 95%CI 1.51∼3.38). No association was observed between cLBP and the Framingham risk score, medication for hyperlipemia, hypertension, diabetes, and major cardiovascular risk factors (systolic blood pressure, total cholesterol, high density lipoprotein cholesterol, triglycerides, glucose and smoking habits) in either men or women.

Conclusions

The prevalence of cLBP is correlated to a history of cardiovascular disease, but not to the major cardiovascular risk factors from the Framingham study. Further studies on whether these results were affected by psychological factors in patients with a history of cardiovascular diseases or whether new potential risk factors from the artery atherosclerosis hypothesis applying to Koreans exist are needed.

Obesity as a risk factor for sciatica: a meta-analysis

The aim of this study was to assess the associations of overweight and obesity with lumbar radicular pain and sciatica using a meta-analysis. We searched the PubMed, Embase, Scopus, and Web of Science databases from 1966 to July 2013. We performed a random-effects meta-analysis and assessed publication bias. We included 26 (8 cross-sectional, 7 case-control, and 11 cohort) studies. Both overweight (pooled odds ratio (OR) = 1.23, 95% confidence interval (CI): 1.14, 1.33; n = 19,165) and obesity (OR = 1.40, 95% CI: 1.27, 1.55; n = 19,165) were associated with lumbar radicular pain. The pooled odds ratio for physician-diagnosed sciatica was 1.12 (95% CI: 1.04, 1.20; n = 109,724) for overweight and 1.31 (95% CI: 1.07, 1.62; n = 115,661) for obesity. Overweight (OR = 1.16, 95% CI: 1.09, 1.24; n = 358,328) and obesity (OR = 1.38, 95% CI: 1.23, 1.54; n = 358,328) were associated with increased risk of hospitalization for sciatica, and overweight/obesity was associated with increased risk of surgery for lumbar disc herniation (OR = 1.89, 95% CI: 1.25, 2.86; n = 73,982). Associations were similar for men and women and were independent of the design and quality of included studies. There was no evidence of publication bias. Our findings consistently showed that both overweight and obesity are risk factors for lumbar radicular pain and sciatica in men and women, with a dose-response relationship.

Associations of metabolic factors and adipokines with pain in incipient upper extremity soft tissue disorders: a cross-sectional study

OBJECTIVES

Earlier studies have suggested associations between metabolic factors and musculoskeletal pain or disorders. We studied the associations of obesity, lipids, other features of the metabolic syndrome and adipokines (adiponectin, leptin, resistin, visfatin) with upper extremity pain in a clinical population with incipient upper extremity soft tissue disorders (UESTDs).

DESIGN

A cross-sectional study.

SETTING

Primary healthcare (occupational health service) with further examinations at a research institute.

PARTICIPANTS

Patients (N=163, 86% were women) seeking medical advice in the occupational health service due to incipient upper extremity symptoms with symptom duration of <1 month were referred for consultation to the Finnish Institute of Occupational Health from Spring 2006 to Fall 2008. We included all actively working subjects meeting diagnostic criteria based on physical examination. We excluded subjects meeting predetermined conditions.

OUTCOME MEASURE

Pain intensity was assessed with visual analogue scale and dichotomised at the highest tertile (cut-point 60).

RESULTS

Obesity (adjusted OR for high waist circumference 2.9, 95% CI 1.1 to 7.3), high-density lipoprotein cholesterol (OR 3.9, 95% CI 1.4 to 10.1 for low level) and triglycerides (OR 2.6, 95% CI 1.0 to 6.8 for high level) were associated with pain intensity. Of four adipokines studied, only visfatin was associated with upper extremity pain (adjusted OR 1.4, 95% CI 1.0 to 2.1 for 1SD increase in level).

CONCLUSIONS

Abdominal obesity and lipids may have an impact on pain intensity in UESTDs. They may intensify pain through proinflammatory pain-modifying molecular pathways or by causing soft tissue pathology and dysfunction of their supplying arteries. Of four adipokines studied only one (visfatin) was associated with pain intensity. In the future, further studies are required to better understand the relationship between metabolic factors and UESTDs.

Body mass index and musculoskeletal pain: is there a connection?

Background

Back pain is one of the most common complaints that patients report to physicians and two-thirds of the population has an elevated body mass index (BMI), indicating they are either overweight or obese. It was once assumed that extra body weight would stress the low back and lead to pain, however, researchers have reported inconsistencies association between body weight and back pain. In contrast, more recent studies do indicate that an elevated BMI is associated with back pain and other musculoskeletal pain syndromes due to the presence of a chronic systemic inflammatory state, suggesting that the relationship between BMI and musculoskeletal pains be considered in more detail.

Objective

To describe how an elevated BMI can be associated with chronic systemic inflammation and pain expression. To outline measurable risk factors for chronic inflammation that can be used in clinical practice and discuss basic treatment considerations.

Discussion

Adiposopathy, or “sick fat” syndrome, is a term that refers to an elevated BMI that is associated with a chronic systemic inflammatory state most commonly referred to as the metabolic syndrome. The best available evidence suggests that the presence of adiposopathy determines if an elevated BMI will contribute to musculoskeletal pain expression. It is not uncommon for physicians to fail to identify the presence of adiposopathy/metabolic syndrome.

Conclusion

Patients with an elevated BMI should be further examined to identify inflammatory factors associated with adiposopathy, such as the metabolic syndrome, which may be promoting back pain and other musculoskeletal pain syndromes.

Obesity is associated with inferior results after surgery for lumbar spinal stenosis: a study of 2633 patients from the Swedish spine register

STUDY DESIGN

A cohort study based on the Swedish Spine Register.

OBJECTIVE

To determine the association between body mass index (BMI) and outcome of lumbar spine surgery for spinal stenosis.

SUMMARY OF BACKGROUND DATA

Several small studies have sought to evaluate the importance of obesity in relation to results after surgery for lumbar spinal stenosis (LSS), but the findings are inconsistent and relatively weak.

METHODS

All patients who underwent surgery for LSS from January 1, 2006, to June 30, 2008, with a completed 2-year follow-up in the Swedish Spine Register were included. Logistic regression was used to assess the association between BMI and different outcomes.

RESULTS

Of the 2633 patients enrolled, 819 (31%) had normal weight, 1208 (46%) were overweight, and 606 (23%) were obese. On average, all 3 BMI groups achieved significant improvements after surgery. A higher BMI, however, was associated with greater odds of dissatisfaction after surgery and inferior results at the 2-year follow-up. After adjusting for differences in baseline characteristics, the obese group demonstrated inferior function and quality of life as measured by the Oswestry Disability Index (ODI) and the EuroQol Group Index (EQ-5D), respectively. At the 2-year follow-up, obese patients had a mean ODI of 33 (95% confidence interval [CI], 31-34) and mean EQ-5D of 0.56 (95% CI, 0.54-0.59) compared with a mean ODI of 25 (95% CI, 24-26) and mean EQ-5D of 0.64 (95% CI, 0.62-0.66) in the normal weight group. When compared with the normal weight patients, the adjusted odds ratio for dissatisfaction was 1.73 in the obese group (95% CI, 1.36-2.19). Differences between the normal weight and overweight groups were modest and therefore could not be considered clinically relevant.

CONCLUSION

Obese patients achieved significant pain reduction, better walking ability, and improved quality of life after surgical treatment of LSS. Nevertheless, obesity was associated with a higher degree of dissatisfaction and poorer outcomes after surgery for LSS.

Risk factors for hospitalization due to lumbar disc disease

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

To study biomechanical factors in relation to symptomatic lumbar disc disease.

SUMMARY OF BACKGROUND DATA

The importance of biomechanical factors in lumbar disc disease has been questioned in the past decade and knowledge from large prospective studies is lacking.

METHODS

The study basis is a cohort of 263,529 Swedish construction workers who participated in a national occupational health surveillance program from 1971 until 1992. The workers' job title, smoking habits, body weight, height, and age were registered at the examinations. The occurrence of hospitalization due to lumbar disc disease from January 1, 1987, until December 31, 2003, was collected from a linkage with the Swedish Hospital Discharge Register.

RESULTS

There was an increased risk for hospitalization due to lumbar disc disease for several occupational groups compared with white-collar workers and foremen. Occupational groups with high biomechanical loads had the highest risks, for example, the relative risk for concrete workers was 1.55 (95% confidence interval [CI], 1.29-1.87). A taller stature was consistently associated with an increased risk. The relative risk for a man of 190- to 199-cm height was 1.55 (95% CI, 1.30-1.86) compared with a man being 170- to 179-cm height. Body weight and smoking were also risk factors, but weaker than height. Workers in the age span of 30 to 39 years had the highest relative risk (RR = 1.87; 95% CI, 1.58-2.23) compared with those aged 20 to 29 years, whereas men aged 60 to 65 years had a lower risk (RR = 0.86; 95% CI, 0.68-1.09).

CONCLUSION

This study indicates that factors increasing the load on the lumbar spine are associated with hospitalization for lumbar disc disease. Occupational biomechanical factors seem to be important, and a taller stature was consistently associated with an increased risk.

Structure and biology of the intervertebral disk in health and disease

The intervertebral disks along the spine provide motion and protection against mechanical loading. The 3 structural components, nucleus pulposus, annulus fibrosus, and cartilage endplate, function as a synergistic unit, though each has its own role. The cells within each of these components have distinct origins in development and morphology, producing specific extracellular matrix proteins that are organized into unique architectures fit for intervertebral disk function. This article focuses on various aspects of intervertebral disk biology and disruptions that could lead to diseases such as intervertebral disk degeneration.

Symptomatic disc herniation and serum lipid levels

Insufficient blood supply to the intervertebral disc (IVD) has been proposed to play a role as causative factor in IVD degeneration. There is an association between IVD diseases and increased risk of dying of ischaemic heart disease. Obesity and tobacco are potential risk factors for degenerative IVD disease. High blood cholesterol and triglycerides serum levels are risk factors for atherosclerosis, and could be responsible for a decreased in the blood supply to the already poor vascularized IVD. We performed a frequency-matched case-control study to determine the serum levels of patients with symptomatic herniated lumbar disc. We examined the fasting serum lipid levels in 384 subjects who were operated at our institution. Group 1 included 169 consecutive patients (115 men and 54 women; mean age: 59.1 years, range 29-85) who underwent surgery for symptomatic disc herniation. Group 2 (control group) included 169 patients (115 men and 54 women; mean age: 61 years, range 26-86) who underwent arthroscopic meniscectomy for a meniscal tear in the same period. These patients were frequency-matched by age (within 3 years) and gender with patients of Group 1. Sera were extracted from blood samples and the concentrations of total cholesterol (TC) and triglycerides (TG) were determined. When comparing the two groups, patients with symptomatic herniated lumbar disc showed statistically significant higher triglyceride concentration (P = 0.02) and total cholesterol concentration (P = 0.01). Serum lipid levels may be a risk factor for IVD pathology. An enhanced understanding of these factors holds the promise of new approaches to the prevention and management of IVD pathology.