Association between serum lipids and low back pain among a middle-aged Japanese population: a large-scale cross-sectional study

Cholesterol transport and beyond: Illuminating the versatile functions of HDL apolipoproteins through structural insights and functional implications

High-density lipoproteins (HDLs) play a vital role in lipid metabolism and cardiovascular health, as they are intricately involved in cholesterol transport and inflammation modulation. The proteome of HDL particles is indeed complex and distinct from other components in the bloodstream. Proteomics studies have identified nearly 285 different proteins associated with HDL; however, this review focuses more on the 15 or so traditionally named "apo" lipoproteins. Important lipid metabolizing enzymes closely working with the apolipoproteins are also discussed. Apolipoproteins stand out for their integral role in HDL stability, structure, function, and metabolism. The unique structure and functions of each apolipoprotein influence important processes such as inflammation regulation and lipid metabolism. These interactions also shape the stability and performance of HDL particles. HDLs apolipoproteins have multifaceted roles beyond cardiovascular diseases (CVDs) and are involved in various physiological processes and disease states. Therefore, a detailed exploration of these apolipoproteins can offer valuable insights into potential diagnostic markers and therapeutic targets. This comprehensive review article aims to provide an in-depth understanding of HDL apolipoproteins, highlighting their distinct structures, functions, and contributions to various physiological processes. Exploiting this knowledge holds great potential for improving HDL function, enhancing cholesterol efflux, and modulating inflammatory processes, ultimately benefiting individuals by limiting the risks associated with CVDs and other inflammation-based pathologies. Understanding the nature of all 15 apolipoproteins expands our knowledge of HDL metabolism, sheds light on their pathological implications, and paves the way for advancements in the diagnosis, prevention, and treatment of lipid and inflammatory-related disorders.

Association between HDL-C and chronic pain: data from the NHANES database 2003-2004

Objective

High-density lipoprotein cholesterol (HDL-C) has been reported to be associated with pain symptoms of various diseases, and its anti-inflammatory and antioxidant mediation is related to the pathogenesis of chronic pain. This study aims to evaluate the relationship between HDL-C levels and chronic pain in American adults.

Methods

This cross-sectional study used data from American adults aged 20 and above during the 2003-2004 National Health and Nutrition Examination Survey (NHANES) cycle. Participants were divided into 4 groups based on HDL-C quartiles. We used chi-square tests and Student's t-tests or Mann-Whitney U tests to analyze categorical variables and continuous variables to compare differences between groups. Multivariate logistic regression analysis was used to study the association between HDL-C levels and the risk of chronic pain. Likelihood ratio tests were used to assess interactions between subgroups, and sensitivity analyses were conducted.

Results

Our final analysis included 4,688 participants, of which 733 (16.4%) had chronic pain. In the multivariate logistic regression model adjusted for covariates, there was a negative correlation between HDL-C levels and chronic pain. Specifically, for every 20 unit increase in HDL-C, the risk of chronic pain decreased by 26%. Compared with the lowest HDL-C quartile (< 43 mg/dL), the highest HDL-C quartile (≥ 64 mg/dL) was associated with a 24% reduction in the risk of chronic pain. No interaction factors affecting the relationship between HDL-C and chronic pain were found in the subgroup analysis.

Conclusion

This study demonstrates a negative association between HDL-C levels and chronic pain in US adults, providing insights into the pathogenesis of chronic pain and potential improvements in chronic pain management strategies.

Dyslipidemia Is Positively Associated with Chronic Low Back Pain in Korean Women: Korean National Health and Nutrition Examination Survey 2010-2012

BACKGROUND

This study aimed to evaluate the association between chronic low back pain (CLBP) and chronic diseases, such as hypertension, diabetes, and dyslipidemia.

METHODS

This study was a retrospective analysis using data from the Korea National Health and Nutrition Examination Survey (KNHANES) between 2010-2012 and included women who answered a questionnaire in the KNHANES asking whether they had low back pain for ≥3 months. Participants were divided into non-CLBP and CLBP groups. For statistical analysis, the Student's t-test, chi-square test, Fisher's exact test, and logistic regression analysis were performed using SPSS.

RESULTS

Of 5961 participants, the non-CLBP group comprised 4098 women and the CLBP group comprised 1863. Adjusted logistic regression model revealed that dyslipidemia was positively associated with CLBP (odds ratio, 1.32; 95% confidence interval, 1.140, 1.530; p < 0.001). However, hypertension and diabetes were not associated with CLBP.

CONCLUSIONS

Our results suggest that proper treatment of dyslipidemia may contribute to lowering the risk of CLBP later in life.

Association Between Hypercholesterolemia and Lumbar Degenerative Back Pain: A Medicare Expenditure Panel Survey (MEPS) Study

Introduction Hypercholesterolemia is known to be a major contributor to the morbidity associated with cardiovascular disease and has been hypothesized to result in degenerative changes to the spine through atherosclerosis of segmental lumbar vessels. The purpose of this study is to determine the relationship between hypercholesterolemia and degenerative lumbar spine conditions in a U.S. cohort. Methods A total of 30,461 participated in the 2018 Medicare Expenditure Panel Survey (MEPS). Of those, 1,063 subjects responded to whether a diagnosis of lumbar disorders with low back pain was present. Odds ratios (OR) were calculated, and logistic regression analyses were adjusted for demographic, education, occupation, cardiovascular and mental health conditions. Results Of the 1,063 respondents, 455 (43%) reported back pain. Mean age of the respondents was 62.7±16.1. Men and women reported back pain at similar rates (43% vs 45%, p=0.664). Age, race, education level and occupation were similar between those with and without back pain (p>0.05). Those with a diagnosis of depression had higher odds of having back pain (p<0.05). Prevalence of back pain in subjects who responded to the back pain diagnosis item on the survey was 42.6%. On univariate analysis, diagnosis of total cholesterol levels was significantly higher in those with a diagnosis of back pain (OR 1.36, 95% CI [1.20-1.54], p<.0001). Multivariable analysis showed that hypercholesterolemia was independently associated with back pain (adjusted OR 1.32, 95% CI [1.04-1.68], p=0.021) after controlling for covariates. Conclusions In this study, subjects with hypercholesterolemia were 34% more likely to have back pain after controlling for confounders which presents as a recent discovery amongst U.S. populations. Further studies should be performed to investigate the management of hypercholesterolemia in the development and progression of degenerative lumbar back pain.

The impact of dyslipidemia on lumbar intervertebral disc degeneration and vertebral endplate modic changes: a cross-sectional study of 1035 citizens in China

BACKGROUND

Intervertebral disc degeneration (IDD) and vertebral endplate Modic changes (MCs) are common lumbar degenerative phenotypes related to low back pain (LBP). Dyslipidemia has been linked to LBP but its associations with IDD and MCs have not been fully elucidated. The present study aimed to address the possible link between dyslipidemia, IDD and MCs in the Chinese population.

METHODS

1035 citizens were enrolled in the study. The levels of serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG) were collected. IDD was evaluated based on the Pfirrmann grading system and subjects with an average grade ≥ 3 were defined as having degeneration. MCs were classified into typical types 1, 2 and 3. Covariables, including age, sex, BMI and fasting plasma glucose, were included for the adjustment of the logistic analyses.

RESULTS

The degeneration group included 446 subjects while the nondegeneration group included 589 subjects. The degeneration group had significant higher levels of TC and LDL-C (p < 0.001) whereas TG and HDL-C were not significantly different between the two groups. TC and LDL-C concentrations were significantly positively correlated with average IDD grades (p < 0.001). Multivariate logistic regression revealed that high TC (≥ 6.2 mmol/L, adjusted OR = 1.775, 95% CI = 1.209-2.606) and high LDL-C (≥ 4.1 mmol/L, adjusted OR = 1.818, 95% CI = 1.123-2.943) were independent risk factors for IDD. Type 1 MC presented in 84 (8.12%) subjects, type 2 MC presented in 244 (23.57%) subjects, type 3 MC presented in 27 (2.61%) subjects and no MC was observed in the remaining 680 (65.70%) subjects. The type 2 MC group demonstrated a higher level of TC, but the association between serum lipids and MCs could not be confirmed in further multivariate logistic regression.

CONCLUSIONS

High TC (≥ 6.2 mmol/L) and LDL-C (≥ 4.1 mmol/L) concentrations were independent risk factors for IDD for citizens in China. However, the association between dyslipidemia and MCs could not be determined. The effect of excess serum cholesterol may be critical for IDD and cholesterol lowering treatment may provide new opportunities in the management of lumbar disc degeneration.

The Importance of Nutrition as a Lifestyle Factor in Chronic Pain Management: A Narrative Review

In everyday clinical practice, healthcare professionals often meet chronic pain patients with a poor nutritional status. A poor nutritional status such as malnutrition, unhealthy dietary behaviors, and a suboptimal dietary intake can play a significant role in the occurrence, development, and prognosis of chronic pain. The relationship between nutrition and chronic pain is complex and may involve many underlying mechanisms such as oxidative stress, inflammation, and glucose metabolism. As such, pain management requires a comprehensive and interdisciplinary approach that includes nutrition. Nutrition is the top modifiable lifestyle factor for chronic non-communicable diseases including chronic pain. Optimizing one’s dietary intake and behavior needs to be considered in pain management. Thus, this narrative review reports and summarizes the existing evidence regarding (1) the nutrition-related health of people experiencing pain (2) the underlying potential mechanisms that explain the interaction between nutrition and chronic pain, and (3) the role of nutrition screening, assessment and evaluation for people experiencing pain and the scope of nutrition practice in pain management. Future directions in the nutrition and chronic pain field are also discussed.

Low Back Pain Physiotherapy: Does Expectation Really Influence Outcome?

Objectives: Low Back Pain (LBP) is prevalent in most people of working age. The morbidity it causes cannot be taken lightly, as is its economic burden. Physiotherapy has long been prescribed to LBP patients, but treatment outcome measurements, along with the factors influencing it, have not been widely evaluated. In this study, we aim to assess the correlation between patient’s expectation and LBP physical therapy outcome. Methods: This was a cross sectional study conducted at physical rehabilitation outpatient clinic in September-December 2019. Participants were patients with LBP who were treated with physical therapy. One series of physical therapy consists of 5 sessions of modality only or modality with exercise therapy; one patient underwent 2 sessions per week. Oswestry disability index (ODI) score was used to evaluate treatment outcome and Stanford Expectation of Treatment Scale score was used to evaluate patient’s expectation. Data was collected twice, before and after 1 series of therapy. Results: There were 91 participants included in this study, most of whom were female. Most patients reported a significant decrease in ODI score, irrespective of the LBP chronicity or nutritional status. However, patients who received a combination of physical exercises and modalities reported lower after therapy ODI than those who only received modalities (p=0.009). No correlation was found between positive (p=0.567) or negative (p=0.910) expectations with ODI improvement. Conclusion: Our study did not find any correlation between positive or negative expectations towards ODI score improvement. Keywords: Low back pain; Physical therapy; Treatment outcome; Patient expectation; ODI score

Cholesterol Induces Pyroptosis and Matrix Degradation via mSREBP1-Driven Endoplasmic Reticulum Stress in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IDD) is closely associated with low back pain, but its underlying mechanism remains unclear. Cholesterol is an essential nutrient in mammalian cells. Alterations in cholesterol levels lead to impairments in cell physiology, such as cell proliferation and signal transduction. Previous clinical studies demonstrated that hypercholesterolemia could be a potential risk factor for IDD, but how cholesterol induces IDD remains unknown. The current study aimed to explore the regulatory role of cholesterol in IDD development and the potential underlying mechanisms. It was found that different forms of cholesterol levels were elevated in degenerative nucleus pulposus (NP) tissues in both humans and Sprague–Dawley rats. Rats fed a high cholesterol diet (HCD) exhibited degenerative features in the lumbar intervertebral disc compared with those fed a standard diet. Interestingly, this effect could be abolished by cholesterol-lowering drug atorvastatin. In NP cells treated with TNF-α and IL-1β, a significantly higher level of cholesterol was observed. These results suggested a pivotal role of cholesterol in the progression of IDD. We also observed accelerated pyroptosis in NP cells and extracellular matrix (ECM) degradation in the rat NP cells treated with exogenous cholesterol. We further demonstrated that endoplasmic reticulum stress was responsible for cholesterol-induced pyroptosis and ECM degradation. Moreover, RNA-seq analysis revealed that the mature form of SREBP1 (mSREBP1), an important regulator of lipid metabolism, is involved in regulating endoplasmic reticulum stress in knockdown experiments. In conclusion, this study demonstrated that cholesterol could induce pyroptosis in NP cells and ECM degradation by activating endoplasmic reticulum stress through stimulating mSREBP1 in IDD.

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.

Effects of body weight and fat mass on back pain - direct mechanical or indirect through inflammatory and metabolic parameters?

BACKGROUND

While reports indicate the association between obesity and back pain, its mechanism is still unclear. Thus, we aimed to investigate the effects of weight and its components on back pain in middle-aged women while considering direct mechanical and indirect effects via inflammatory and metabolic parameters.

METHODS

We used data from the Chingford 1000 Women Study, two follow-ups seven years apart. We assessed effects of weight, body mass index (BMI), total fat mass (TFM), total lean mass (TLM) and total bone mineral density (TBMD), measured by dual-energy X-ray absorptiometry, on back pain episode. We used inflammatory (C-reactive protein, interleukin-6, and tumour necrosis factor-alpha) and metabolic parameters (systolic and diastolic blood pressure, triglyceride, high-density lipoprotein cholesterol, and fasting blood glucose) as mediators of indirect effects. We investigated associations of interest cross-sectionally and longitudinally using binary logistic regression and parallel mediation model.

RESULTS

We included 826 Chingford middle-aged women (mean age=60.7, SD=5.9) from the first used follow-up in cross-sectional and mediation analyses and 645 women that attended the follow-up seven years later, in longitudinal analyses. We found that increased weight was directly associated with increased odds of having back pain episode (OR=1.02; 95% CI 1.01-1.03), similarly as BMI (OR=1.05; 95% CI 1.02-1.08) and TFM (OR=1.03; 95% CI 1.01-1.04) consistently across the cross-sectional and longitudinal models, but not TLM or TBMD. However, we did not find consistent indirect effects of weight or its components through measured inflammatory or metabolic parameters on back pain.

CONCLUSIONS

Our results show that in middle-aged women, weight, BMI and TFM are directly related to back pain, indicating prominence of mechanical loading effect.

Hepatic Steatosis Index and Chronic Kidney Disease among Middle-Aged Individuals: A Large-Scale Study in Japan

BACKGROUND

Though nonalcoholic fatty liver disease (NAFLD) is related to chronic kidney disease (CKD), it is unclear whether the hepatic steatosis index (HSI), a screening tool for NAFLD, is related to CKD. The present study investigated the relationship between HSI and CKD among middle-aged individuals in Japan.

METHODS

Subjects were adults (aged 40-64 years) who received an annual health checkup in Japan between April 2013 and March 2014. Height and weight were measured, and venous blood samples were obtained to determine alanine aminotransferase (ALT), aspartate aminotransferase (AST), and creatinine levels. HSI was calculated by the following formula: HSI = 8 × ALT/AST ratio + body mass index (+2, if diabetes; +2, if female). CKD was defined as an estimated glomerular filtration rate < 60 mL/min/1.73 m2 and/or urinary protein of ≥ (+). Logistic regression analysis was performed to estimate the odds ratio (OR) and its 95% confidence interval (CI) for CKD.

RESULTS

Data of 94,893 adults were analyzed. Compared with men with an HSI < 30, men with 30 ≤ HSI ≤ 36 (OR: 1.50, 95% CI: 1.40-1.61) and HSI > 36 (OR: 2.14, 95% CI: 1.99-2.31) had significantly higher ORs for CKD. Moreover, there was a significant dose-response relationship between HSI and CKD (P for trend < 0.001). Even after adjusting for confounders, the significant results persisted. These findings in men were similar to those in women.

CONCLUSIONS

This study showed that the HSI was associated with CKD among middle-aged adults in Japan. Additionally, a dose-response relationship of HSI to CKD was observed. The present study suggested that it might be useful to monitor the HSI among middle-aged individuals to detect CKD at an early stage.

Association of LDLc to HDLc ratio with carotid plaques in a community-based population with a high stroke risk: A cross-sectional study in China

BACKGROUND AND AIMS

The association between low-density lipoprotein cholesterol (LDLc) to high-density lipoprotein cholesterol (HDLc) ratio (LDLc/HDLc) and carotid plaques remains controversial. We conducted a cross-sectional study to evaluate whether LDLc/HDLc is associated with carotid plaques in individuals with a high-stroke-risk.

METHODS AND RESULTS

The study initially enrolled 5529 residents aged 40 years or older from Yangzhou, China in 2013-2014. All participants received a questionnaire interview, physical examination, and laboratory tests. Risk factors for stroke included hypertension, diabetes mellitus, dyslipidemia, atrial fibrillation, smoking, less exercise, overweight/obesity, and family stroke history. Subjects with at least three of the risk factors or a history of stroke/transient ischemic attack (TIA) were defined as a high-stroke-risk population. Carotid ultrasonography was only conducted for this high-stroke-risk population. Logistic regression was used to examine the association of LDLc/HDLc with the presence of carotid plaques. Final analysis included 839 high-stroke-risk subjects and 40.6% were identified to have carotid plaques. Subjects with the highest tertiles group of LDLc/HDLc had a higher proportion of carotid plaques than the other two groups (47.1% vs. 34.6% and 40.4%, P < 0.001). With each unit increase of LDLc/HDLc, the chance of having carotid plaques increased by 65% (OR 1.65, 95%CI 1.31-2.08) after adjusted for potential confounders. Among most subgroups, a higher LDLc/HDLc was significantly correlated with the presence of carotid plaques.

CONCLUSION

Higher LDLc/HDLc was significantly associated with the presence of carotid plaques in the Chinese population with a high risk of stroke.

Strain-based work-to-family conflict as a predictor of lumbar and cervical pain in Tunisian nursing staff

Objective. This study aimed to examine the association of the different dimensions and forms of work-family conflict with the occurrence of neck and lower back pain (LBP) in Tunisian nurses. Methods. We conducted a cross-sectional study on nurses assigned to a district hospital in Tunisia. The work-family interface was assessed with the work-family conflict scale of Carlson et al. Psychosocial and organizational constraints at work were assessed through the nursing work index - extended organization in its specific version designed for nurses. Assessment of neck and lumbar pain was carried out with the standardized Nordic musculoskeletal questionnaire. Results. Seventy-two nurses participated in the present study (participation rate = 100%) with a mean age of 42.38 ± 10.85 years. Binary logistic regression analyses retained strain-based work-to-family conflict as a significant determinant of both LBP (p < 10^-3; odds ratio [OR] = 5.07; 95% confidence interval [CI] [2.1, 11.7]) and neck pain (p = 0.001; OR = 6.8; 95% CI [2.13, 22]). Conclusions. Strain-based work-to-family conflict was found to predict lumbar and cervical pain more than the other types of conflict in nursing staff. Thus, reducing strain in health-care settings should be a central component of the preventive approach of musculoskeletal disorders in nursing staff.

Hypoxic stress enhances extension and branching of dorsal root ganglion neuronal outgrowth

It has been shown that painful intervertebral discs (IVDs) were associated with a deeper innervation. However, the effect of the disc's degenerative microenvironment on neuronal outgrowth remains largely unknown. The focus of this study was to determine the influence of hypoxia on dorsal root ganglion (DRG) neurite outgrowth. Toward this aim, the DRG-derived cell line ND7/23 was either directly subjected to 2% or 20% oxygen conditions or exposed to conditioned medium (CM) collected from IVDs cultured under 2% or 20% oxygen. Viability and outgrowth analysis were performed following 3 days of exposure. Results obtained with the cell line were further validated on cultures of rabbit spinal DRG explants and dissociated DRG neurons. Results showed that hypoxia significantly increased neurite outgrowth length in ND7/23 cells, which was also validated in DRG explant and primary cell culture, although hypoxia conditioned IVD did not significantly increase ND7/23 neurite outgrowth. While hypoxia dramatically decreased the outgrowth frequency in explant cultures, it significantly increased collateral sprouting of dissociated neurons. Importantly, the hypoxia-induced decrease of outgrowth frequency at the explant level was not due to inhibition of outgrowth branching but rather to neuronal necrosis. In summary, hypoxia in DRG promoted neurite sprouting, while neuronal necrosis may reduce the density of neuronal outgrowth at the tissue level. These findings may help to explain the deeper neo-innervation found in the painful disc tissue.

HIGHLIGHTS

Hypoxia promoted elongation and branching of neurite outgrowth at single cell level, but reduced outgrowth density at tissue level, possibly due to hypoxia-induced neuronal necrosis; these findings may help to explain the deeper neo-innervation found in clinically painful tissues.

Sex differences in the association of metabolic syndrome with low back pain among middle-aged Japanese adults: a large-scale cross-sectional study

BACKGROUND

Although some recent studies have indicated an association between metabolic syndrome (MetS) and musculoskeletal disease, little is known about the association of MetS with low back pain (LBP). The present study aimed to investigate sex differences in the association of MetS and the clustering of MetS components with LBP among middle-aged Japanese individuals.

METHODS

Study subjects were 45,192 adults (30,695 men, 14,497 women) aged 40-64 years who underwent annual health checkups conducted from April 2013 to March 2014. MetS was defined according to the criteria of the Examination Committee of Criteria for MetS in Japan as abdominal obesity plus at least two of dyslipidemia, high blood pressure, or high blood glucose. Information on LBP and health-related lifestyles were collected using a self-administered questionnaire. Logistic regression modeling was used to calculate the odds ratio (OR) and 95% confidence interval (CI) for LBP.

RESULTS

After adjusting for age and lifestyle factors, the OR of MetS for LBP was 1.15 (95% CI 0.95-1.40) in men and 2.16 (95% CI 1.32-3.53) in women. Compared to subjects without abdominal obesity, the presence of abdominal obesity significantly increased the OR for LBP among men (abdominal obesity only: OR 1.34, 95% CI 1.02-1.76; abdominal obesity plus one component: OR 1.24, 95% CI 1.01-1.52; abdominal obesity plus two or more components: OR 1.26, 95% CI 1.02-1.55). Among women, adding other components of MetS to abdominal obesity significantly increased ORs for LBP (abdominal obesity only: OR 1.70, 95% CI 0.94-3.08; abdominal obesity plus one component: OR 1.66, 95% CI 1.06-2.60; abdominal obesity plus two or more components: OR 2.30, 95% CI 1.41-3.78).

CONCLUSIONS

This large-scale cross-sectional study indicated that MetS was significantly associated with LBP among women only and that a sex-difference existed in the association between the clustering of MetS components and LBP. Clustering of MetS components by sex may need to be considered for the prevention of LBP, although further prospective studies are needed to clarify the causality.