Obesity does not increase the risk of chronic low back pain when genetics are considered. A prospective study of Spanish adult twins

Hip and waist circumference correlations with demographic factors and pain intensity in patients with chronic pain

Aim: This study aimed to investigate how demographic factors such as race, age, sex and ethnicity can impact hip circumference (HC) and waist circumference (WC) in patients with chronic pain.Materials & methods: We queried the NIH-sponsored All of Us database for patients with documented HC, WC and waist/hip ratio (WHR) data. This cross-sectional study categorized participants into four groups: total cohort, no chronic pain, mild/moderate chronic pain (numeric rating scale < 7) and severe chronic pain (numeric rating scale > 7). Further subgroup analyses were performed based on race, age, sex and ethnicity. We examined the correlation between chronic pain and WC, HC and WHR. ANCOVA analysis was used to determine to investigate demographics.Results: This study included 204,013 participants, with 25.22% having a chronic pain diagnoses. In most subgroups, females had significantly greater HC, while males had greater WC and WHR. WC (p < 0.001 in females, p < 0.01 in males), HC (p < 0.001 in females) and WHR (p < 0.001 in females, p < 0.05 in males) were significantly greater in the severe pain group compared with the mild/moderate pain group.Conclusion: These findings suggest that when assessing HC and WC, demographic variables need to be considered to develop more personalized and comprehensive treatment plans for chronic pain patients.

Chronic Pain and Obesity in Community-Dwelling Adults: Findings from the National Health and Nutrition Examination Survey

Background

Chronic pain and obesity, together with their corresponding characteristics, are concerning health issues with high socioeconomic burden. The objective of this study is to ascertain the prevalence of chronic pain among individuals residing in the community and examine its association with obesity.

Methods

The present study employed a cross-sectional design and analyzed data from three cycles of the National Health and Nutrition Examination Survey (NHANES). Univariate and multivariate logistic regression analysis were performed to examine the relationship between chronic pain and obesity. To evaluate the potential nonlinear association of chronic with body mass index (BMI), the restricted cubic spline (RCS) analysis was performed in multivariable-adjusted models. The researchers conducted subgroup analyses in order to investigate the potential influence of different confounding factors on the relationship between chronic pain and obesity.

Results

Our final analysis included a sample size of 13,700 participants with higher prevalence of chronic pain with higher BMI, older age, female sex, lower educational level, smoking, and other pathologies. The prevalence of chronic pain in different BMI groups was 17.0% (underweight), 11.8% (normal weight), 12.9% (overweight), and 17.9% (obesity), respectively. In the fully adjusted model, obesity was associated with a 45% increase in the risk of chronic pain compared with the normal weight. The RCS analyses revealed a nonlinear and J-shaped positive association between BMI and chronic pain (OR 1.45, 95% CI 1.27-1.66, all P for nonlinearity < 0.05). The results of the subgroup analyses indicate that the presence of osteoporosis significantly influenced the relationship between obesity and chronic pain, as evidenced by a statistically significant interaction effect (OR 2.25, 95% CI 1.38-3.68, P for interaction = 0.019).

Conclusion

The presence of obesity was found to be significantly correlated with an increased likelihood of experiencing chronic pain among adults living in the United States.

Relative Recovery of Non-Alcoholic Fatty Liver Disease (NAFLD) in Diet-Induced Obese Rats

Consumption of a high-carbohydrate diet has a critical role in the induction of weight gain and obesity-related pathologies. This study tested the hypothesis that a carbohydrate-rich diet induces weight gain, ectopic fat deposition, associated metabolic risks and development of non-alcoholic fatty liver disease (NAFLD), which are partially reversible following carbohydrate reduction. Sprague Dawley (SD) rats were fed a carbohydrate-enriched cafeteria diet (CAF) or normal chow (NC) ad libitum for 16-18 weeks. In the reversible group (REV), the CAF was replaced with NC for a further 3 weeks (18-21 weeks). Animals fed the CAF diet showed significantly increased body weight compared to those fed NC, accompanied by abnormal changes in their systemic insulin and triglycerides, elevation of hepatic triglyceride and hepatic steatosis. In the REV group, when the CAF diet was stopped, a modest, non-significant weight loss was associated with improvement in systemic insulin and appearance of the liver, with lower gross fatty deposits and hepatic triglyceride. In conclusion, a carbohydrate-enriched diet led to many features of metabolic syndrome, including hyperinsulinemia, while a dietary reduction in this macronutrient, even for a short period, was able to restore normoinsulinemia, and reversed some of the obesity-related hepatic abnormalities, without significant weight loss.

Association between body composition and chronic low back pain in Korean adults aged over 50 years: The Korea National Health and Nutrition Examination Survey (KNHANES) 2010-2011

Background The relationship between overweight or obesity and low back pain (LBP) has previously been investigated. Several recent studies have focused on the relationship between other indicators of obesity, particularly indicators of fat and the risk of LBP. However, the results of body composition and LBP have been inconsistent. Methods All data for the present retrospective, cross-sectional study was extracted from the Korea National Health and Nutrition Examination Survey (KNHANES) versions V-1 and 2 conducted in 2010 and 2011 by the Korean Centers for Disease Control and Prevention. In KNHANES V-1 (2010) and V-2 (2011), those over 50 years of age completed the surveys on LBP, body weight, and body composition assessed using dual-energy X-ray absorptiometry (DXA) were included. The multivariable logistic regression analysis was used to examine the relationship between the presence of chronic LBP and body composition adjusting for confounders. Results We analyzed 3,579 persons who completed the question. In the multivariable analyses adjusting for age and sex, none of the variables, including fat mass and fat-free mass, remained positively or negatively associated with LBP. Additionally, when depression, smoking, alcohol intake, physical activity, diabetes mellitus, and fat or lean tissue mass were included in the multivariable logistic model, no significant associations were found between all measures of fat mass, fat-free mass, and LBP Conclusion This study is contrary to previous studies that concluded that there is a correlation between obesity and fat mass and LBP. LBP is not associated with increased levels of obesity and fat mass.

Association Between Body Mass Index and Nonspecific Recurrent Low Back Pain in Over 600,000 Healthy Young Adults

An association between body mass index (BMI; weight (kg)/height (m)2) and low back pain (LBP) has long been debated, but inconsistent measurements of BMI and varying definitions of LBP have produced conflicting findings. We explored this association using measured BMI and physician documentation of recurrent LBP among healthy young adults. Data were extracted from the Israel Defense Forces electronic medical record system. All Israeli citizens with compulsory military service during January 2008-March 2019 were included (n = 705,840). Exclusion criteria were spine deformities, disc pathologies, spinal surgeries, arthropathies, connective tissue diseases, pain syndromes, low bone density disorders, cancers, and psychiatric illnesses. LBP was defined as electronic medical record system documentation of 1) 2 medical visits at least 6 weeks apart with a diagnosis of LBP or "LBP with radiation" or 2) 1 medical visit resulting in referral to an orthopedic surgeon. Logistic regression models were used to explore the association between BMI category and LBP; 619,969 (87.8%) individuals (mean age = 18.9 (standard deviation, 0.97) years; 56.9% male) were included. LBP prevalence was 9.2% (n = 56,918) and higher among males (9.7%) than females (8.5%). Overweight (odds ratio = 1.123, 95% confidence interval: 1.096, 1.151) and obesity (odds ratio = 1.137, 95% confidence interval: 1.096, 1.179) were associated with LBP. The association remained significant after accounting for various sociodemographic factors. Maintaining a healthy BMI may aid in the prevention of LBP in young adults.

The Effects of Body Composition Characteristics on the Functional Disability in Patients with Degenerative Lumbar Spinal Stenosis

Several research studies suggest that obese patients are at a higher risk of developing lumbar spinal disorder, including degenerative lumbar spinal stenosis (LSS), compared to normal-weight individuals. However, there are few investigations of how obesity affects functional disability in activities of daily living (ADL) in patients who were diagnosed with LSS. This prospective observational study aimed to determine if an association exists between body composition parameters, such as body fat and skeletal muscle, and functional disability in ADL of LSS patients. In the results of the current study, there were significant differences in percent body fat between the mild/moderate and severe disability groups. However, there were no differences in skeletal muscle mass or index between the two groups. Furthermore, we found a positive linear relationship between percent body fat and functional disability in male sex. This study suggests that increased percent body fat predicts potential severe functional disability in ADL in LSS patients. Body composition analysis may provide useful information for predicting the disease severity of various lumbar spinal disorders in clinical practice.

Bidirectional associations between body mass and bodily pain among middle-aged and older adults

ABSTRACT

Higher body mass and obesity are associated with bodily pain, and rates of chronic pain increase among older adults. Most past studies are cross-sectional, precluding determination of the temporal relationship between body mass and pain. A longitudinal study of body mass and pain among middle-aged adults found that higher body mass index (BMI) led to greater lower back pain. No longitudinal study of BMI and pain has been conducted among adults older than 70 years. This study used dual change score models to determine the directional relationship between BMI and bodily pain in a sample of middle-aged and older adults. Participants (n = 1889) from the Swedish Twin Registry (baseline age range 40-93 years) completed at least 1 nurse assessment of BMI and self-report ratings of pain interference and joint pain. Pain interference was not associated with BMI, but joint pain was analyzed in univariate and bivariate models, with dual change score models modeling the relationship of BMI and joint pain across age, both independently and as part of bivariate relationships. The results indicated a reciprocal relationship between BMI and joint pain, but joint pain generally led to changes in BMI. In addition, the relationship changed with age, until approximately age 80 years, increasing joint pain contributed to higher BMI, but after that time increasing joint pain contributed to lower BMI. In addition, sex differences in the relationship between BMI and pain appeared after age 70 years. Thus, joint pain contributes to changes in BMI among middle-aged and older adults, but the relationship may change by age and sex.

Prevalence and Related Factors of Low Back Pain in the General Elderly Population: A Japanese Cross-Sectional Study Randomly Sampled from a Basic Resident Registry

Low back pain (LBP) is one of the main etiologies of disability in daily life. In the face of LBP increases in super-aged societies, there are serious concerns of escalating medical costs and deteriorations in the social economy. It is therefore important to identify the factors associated with LBP for prompt preventative and therapeutic measures. This study investigated the prevalence of LBP and the impact of subject-specific factors on LBP development in Japanese community-dwelling older adults. We established eight groups based on age (50's, 60's, 70's, and 80's) and gender after random sampling from a resident registry. A total of 411 participants (201 male and 210 female) were enrolled for a whole-spine lateral radiographic examination and dual-energy X-ray absorptiometry. All subjects were evaluated for the presence and degree of LBP. We analyzed the impact of clinical factors on LBP using multivariate analysis. Fifty-three (12.9%) participants (23 (11.4%) male and 30 (14.3%) female) were found to have LBP. The prevalence of LBP tended to increase with age, and similar results were found between genders. In univariate analysis, the subject-related factors of the sagittal vertebral axis, pelvic incidence minus lumbar lordosis (PI-LL) mismatch, and aging had significant associations with LBP. PI-LL mismatch was a significant independent factor in multivariate analysis. In conclusion, this study identified LBP prevalence and subject-specific factors on a general population basis. Multivariate analysis revealed PI-LL mismatch as an independent factor associated with LBP in the healthy community-dwelling elderly.

Is adiposity associated with back and lower limb pain? A systematic review

BACKGROUND

Back and lower limb pain have a major impact on physical function and quality of life. While obesity is a modifiable risk factor for musculoskeletal pain, the role of adiposity is less clear. This systematic review aimed to examine the relationship between both adiposity and its distribution and back and lower limb pain.

METHODS

A systematic search of electronic databases was conducted to identify studies that examined the association between anthropometric and/or direct measures of adiposity and site specific musculoskeletal pain. Risk of bias was assessed and a best evidence synthesis was performed.

RESULTS

A total of 56 studies were identified which examined 4 pain regions, including the lower back (36 studies), hip (two studies), knee (13 studies) and foot (eight studies). 31(55%) studies were assessed as having low to moderate risk of bias. 17(30%) studies were cohort in design. The best evidence synthesis provided evidence of a relationship between central adiposity and low back and knee pain, but not hip or foot pain. There was also evidence of a longitudinal relationship between adiposity and the presence of back, knee and foot pain, as well as incident and increasing foot pain.

CONCLUSIONS

This systematic review provides evidence of an association between both body fat and its central distribution and low back and knee pain, and a longitudinal relationship between adiposity and back, knee and foot pain. These results highlight the potential for targeting adiposity in the development of novel treatments at these sites.

Research Relating to Low Back Pain and Physical Activity Reported Over the Period of 2000-2020

BACKGROUND

Low back pain (LBP) is a highly prevalent musculoskeletal disorder that contributes to the greatest degree of disability worldwide. It has become a very serious public health problem that has attracted considerable research interest. The number of publications associated with LBP and physical activity (PA) is gradually increasing. Nevertheless, few studies have utilised visualisation in analysing the general aspects of this field. Therefore, we aimed to provide a systematic overview of global scientific research related to low back pain and physical activity from 2000 to 2020. It has significant benefits in terms of providing researchers with the status and trends of research on low back pain and physical activity.

METHODS

Publications on Science Citation Index-Expanded of Web of Science from 2000 to 2020 were searched, and publications relevant to LBP and PA were analysed using Citespace and SPSS. Analyses mainly included cooperation amongst authors, countries and institutions; co-occurrence analysis of keywords; and co-citation analysis of references, revealing productive researchers and contributing institutions tracking the status and trend of research fields.

RESULTS

Results of linear regression analysis showed that the number of publications on LBP and PA studies increased significantly (p<0.001). The subject categories predominantly focused on orthopaedics (2579, 26.54%), rehabilitation (2544, 26.18%) and sport sciences (2015, 25.44%). The United States had the highest number of published papers (2700, 27.789%) and citations (86, 958). In terms of the number of publications, amongst the top 20 journals, Spine contributed the most, whilst the British Journal of Sports Medicine had the highest impact factor (IF2019, 12.022). The University of Sydney had the highest number of publications (330 publications). Maher published the most papers (123 papers) and had the highest H-index (41). Several citation articles and keywords (such as aerobic, obesity and fear-avoidance beliefs) can be used to provide frontier clues for research on LBP and PA.

CONCLUSION

The results of our study may provide information, such as research trends and frontiers of research and collaborating partners, institutions and countries, on LBP and PA.

Prognostic factors for pain chronicity in low back pain: a systematic review

Supplemental Digital Content is Available in the Text.

Several prognostic factors are related to low back pain chronicity, and these should be taken into account when planning more comprehensive models in its prevention.

Low back pain is the leading cause for years lived in disability. Most people with acute low back pain improve rapidly, but 4% to 25% of patients become chronic. Since the previous systematic reviews on the subject, a large number of new studies have been conducted. The objective of this article was to review the evidence of the prognostic factors behind nonspecific chronic low back pain. A systematic literature search was performed without date limitation from the MEDLINE, Cochrane library, and Medic databases. Specific inclusion criteria were used, and risk factors before the onset of chronic symptoms were searched. Study quality was assessed by 2 independent reviewers. One hundred eleven full articles were read for potential inclusion, and 25 articles met all the inclusion criteria. One study was rated as good quality, 19 studies were rated as fair quality, and 5 articles were rated as poor quality. Higher pain intensity, higher body weight, carrying heavy loads at work, difficult working positions, and depression were the most frequently observed risk factors for chronic low back pain. Maladaptive behavior strategies, general anxiety, functional limitation during the episode, smoking, and particularly physical work were also explicitly predictive of chronicity. According to this systematic review, several prognostic factors from the biomechanical, psychological and psychosocial point of view are significant for chronicity in low back pain.

Factors associated with seeking medical care for low back pain in a twin adult sample

BACKGROUND

Previous studies have only investigated how symptom presentation and socio-demographic factors influence care-seeking for low back pain (LBP). However, the influence of health and lifestyle factors remains unclear, and the potential confounding effects of aggregated familial factors (including genetics and the early shared environment) has not been considered extensively.

METHODS

A cross-sectional analysis was performed on 1605 twins enrolled in the Murcia Twin Registry (Spain). The outcome was seeking medical care for LBP and various self-reported demographic, health and lifestyle factors were considered predictors. All variables except sleep quality and diabetes were collected in 2013, which were cross-referenced from 2009 to 2010. A multivariate logistic regression model was performed on the total sample, followed by a co-twin case-control analysis.

RESULTS

The only significant factor found to increase the odds of seeking medical care for LBP without being affected by familial factors was poor sleep quality (total sample OR = 1.58, 95%CI 1.24-2.01; case-control OR = 1.75, 95%CI 1.14-2.69). The factors that were associated with reduced odds of seeking medical care for LBP and not confounded by familial factors were male sex (case-control OR = 0.55, 95%CI 0.33-0.93), alcohol intake (case-control OR = 0.90, 95%CI 0.82-0.99) and a history of diabetes (case-control OR = 0.50, 95%CI 0.25-0.97). No other factors significantly influenced medical care-seeking for LBP.

CONCLUSIONS

People reporting poor sleep quality are more likely to seek medical care for LBP in the long term, with this relationship being independent from aggregated familial factors. Conversely, males, people reporting higher alcohol intake, and people with a history of diabetes are less likely to seek medical care for LBP.

SIGNIFICANCE

This is the first study investigating the factors that influence seeking medical care for LBP, while adjusting for the influence of familial factors using a co-twin control design. Poor sleep quality is associated with seeking medical care for LBP in the long term and does not appear to be confounded by familial factors. Early screening for indicators of poor sleep quality and appropriate referral to interventions for improving sleep quality or reducing pain in sleep may improve LBP management.

Association between low back pain and body mass index in adult twins: an analysis of monozygotic and dizygotic twins of the Washington State Twin Registry

BACKGROUND CONTEXT

Low back pain (LBP) is a common and significant cause of disability worldwide, however; questions about cause still remain.

PURPOSE

To investigate the association between LBP, body mass index (BMI), and moderate to vigorous physical activity (MVPA) in a twin sample.

STUDY DESIGN

Cross sectional study of monozygotic (MZ) and dizygotic (DZ) twins from the Washington State Twin Registry.

PATIENT SAMPLE

Monozygotic and dizygotic twins from the Washington State Twin Registry.

OUTCOME MEASURES

Self-report measures: Low back pain, body mass index, duration and intensity of exercise.

METHODS

The sample included 5,183 same-sex pairs (69% MZ). The outcome was self-reported diagnosis of LBP from a health care provider. A phenotypic model tested the association between BMI and LBP without including genetic or shared environmental confounds. We then re-estimated the association using a quasi-causal model which controls for those confounds. Finally, we used a mediation model to investigate if the association between LBP and MVPA was mediated by BMI.

RESULTS

In the phenotypic regression of LBP on BMI, there was a ~4-fold increase in the odds of having LBP with every one-unit increase in BMI (odds ratio [OR] =3.83; 95% confidence interval =3.28, 4.46). However, quasi-causal regression of LBP on BMI was reduced to zero (OR =0.95; 95% confidence interval =0.60, 1.49). A significant genetic background to BMI and LBP was present (b_A =1.66; p<.001), even after controlling for confounders. In another analysis there was a significant direct effect between MVPA and LBP (b_p=-0.092, standard error [SE] =0.017, p<.001). In mediation analysis, the effect of MVPA on LBP was partially mediated through MVPA effects on BMI ( [Formula: see text] =-0.043, SE=0.003, p<.001) and BMI effects on LBP ( [Formula: see text] =1.281, SE=0.079, OR=3.6, p<.001), however shared environmental factors confounded this relationship.

CONCLUSIONS

BMI was not associated with LBP, despite sharing a phenotypic association, but they may share a genetic influence. The effect of MVPA on LBP is, in part, mediated by BMI but shared environment confounds this relationship.

LEVEL OF EVIDENCE

Level 3.

ISSLS Prize in Clinical Science 2020. Examining causal effects of body mass index on back pain: a Mendelian randomization study

PURPOSE

Measures of body fat accumulation are associated with back pain, but a causal association is unclear. We hypothesized that BMI would have causal effects on back pain. We conducted a two-sample Mendelian randomization (MR) study to assess the causal effect of body mass index (BMI) on the outcomes of (1) back pain and (2) chronic back pain (duration > 3 months).

METHODS

We identified genetic instrumental variables for BMI (n = 60 variants) from a meta-analysis of genome-wide association studies (GWAS) conducted by the Genetic Investigation of ANthropometric Traits consortium in individuals of European ancestry (n = 322,154). We conducted GWAS of back pain and chronic back pain (n = 453,860) in a non-overlapping sample of individuals of European ancestry. We used inverse-variance weighted (IVW) meta-analysis as the primary method to estimate causal effects.

RESULTS

The IVW analysis showed evidence supporting a causal association of BMI on back pain, with a 1-standard deviation (4.65 kg/m²) increase in BMI conferring 1.15 times the odds of back pain (95% confidence interval [CI]: 1.06-1.25, p = 0.001]; effects were directionally consistent in secondary analysis and sensitivity analyses. The IVW analysis supported a causal association of BMI on chronic back pain (OR 1.20 per 1 SD deviation increase in BMI [95% CI 1.09-1.32; p = 0.0002]), and effects were directionally consistent in secondary analysis and sensitivity analyses.

CONCLUSION

In this first MR study of BMI and back pain, we found a significant causal effect of BMI on both back pain and chronic back pain. These slides can be retrieved under Electronic Supplementary Material.

High baseline fat mass, but not lean tissue mass, is associated with high intensity low back pain and disability in community-based adults

Objectives

Low back pain is the largest contributor to disability worldwide. The role of body composition as a risk factor for back pain remains unclear. Our aim was to examine the relationship between fat mass and fat distribution on back pain intensity and disability using validated tools over 3 years.

Methods

Participants (aged 25–60 years) were assessed at baseline using dual-energy X-ray absorptiometry (DXA) to measure body composition. All participants completed the Chronic Pain Grade Scale at baseline and 3-year follow-up. Of the 150 participants, 123 (82%) completed the follow-up.

Results

Higher baseline body mass index (BMI) and fat mass (total, trunk, upper limb, lower limb, android, and gynoid) were all associated with high intensity back pain at either baseline and/or follow-up (total fat mass: multivariable OR 1.05, 95% CI 1.01–1.09, p < 0.001). There were similar findings for all fat mass measures and high levels of back disability. A higher android to gynoid ratio was associated with high intensity back pain (multivariable OR 1.04, 95% CI 1.01–1.08, p = 0.009). There were no associations between lean mass and back pain.

Conclusions

This cohort study provides evidence for the important role of fat mass, specifically android fat relative to gynoid fat, on back pain and disability.

Back pain and sagittal spine alignment in obese patients eligible for bariatric surgery

OBJECTIVE

The objective of this research was to evaluate the prevalence of cervical and lumbar pain in obese patients eligible for bariatric surgery and to investigate possible changes in sagittal spine alignment in these patients.

METHODS

The following parameters were compared in 30 obese patients and a control group of 25 non-obese volunteers: body mass index, prevalence of cervical and lumbar pain assessed by visual analog scale (VAS), Neck Disability Index [NDI] and Oswestry Disability Index [ODI], as well as radiographic parameters of the spine and pelvis measured with Surgimap software.

RESULTS

The cervical and lumbar VAS and the NDI and ODI were significantly worse in obese patients. Compared with the control group, the cervical sagittal vertical axis (cSVA) of the obese group had higher variance (p value = 0.0025) and the cervical lordosis was diminished (p value = 0.0023). Thoracic kyphosis, lumbar lordosis, and the pelvic parameters were not significantly different between the groups.

CONCLUSIONS

Obese patients demonstrated lower functional performance compared with their non-obese counterparts, while cervical lordosis was diminished and the cSVA was increased in obese patients. These slides can be retrieved under Electronic Supplementary Material.

Elevated glycohemoglobin HbA1c is associated with low back pain in nonoverweight diabetics

BACKGROUND CONTEXT

Low back pain (LBP) is a common complaint in clinical practice of multifactorial origin. Although obesity has been thought to contribute to LBP primarily by altering the distribution of mechanical loads on the spine, the additional contribution of obesity-related conditions such as diabetes mellitus (DM) to LBP has not been thoroughly examined.

PURPOSE

To determine if there is a relationship between DM and LBP that is independent of body mass index (BMI) in a large cohort of adult survey participants.

STUDY DESIGN

Retrospective analysis of prospectively collected National Health and Nutrition Examination Survey (NHANES) data to characterize associations between LBP, DM, and BMI in adults subdivided into 6 subpopulations: normal weight (BMI 18.5-25), overweight (BMI 25-30), and obese (BMI >30) diabetics and nondiabetics. Diabetes was defined with glycohemoglobin A1c (HbA1c) ≥6.5%.

PATIENT SAMPLE

11,756 participants from NHANES cohort.

OUTCOME MEASURES

Percentage of LBP reported.

METHODS

LBP reported in the 1999-2004 miscellaneous pain NHANES questionnaire was the dependent variable examined. Covariates included HbA1c, BMI, age, and family income ratio to poverty as continuous variables as well as race, gender, and smoking as binary variables. Individuals were further subdivided by weight class and diabetes status. Regression and graphical analyses were performed on the study population as a whole and also on subpopulations.

RESULTS

Increasing HbA1c did not increase the odds of reporting LBP in the full cohort. However, multivariate logistic regression of the 6 subpopulations revealed that the odds of LBP significantly increased with increasing HbA1c levels in normal weight diabetics. No other subpopulations reported significant relationships between LBP and HbA1c. LBP was also significantly associated with BMI for normal weight diabetics and also for obese subjects regardless of their DM status.

CONCLUSIONS

LBP is significantly related to DM status, but this relationship is complex and may interact with BMI. These results support the concept that LBP may be improved in normal weight diabetic subjects with improved glycemic control and weight loss, and that all obese LBP subjects may benefit from improved weight loss alone.

Contributions of birthweight, annualised weight gain and BMI to back pain in adults: a population-based co-twin control study of 2754 Australian twins

PURPOSE

To investigate associations between anthropometric measures (birthweight, weight gain and current BMI) and back pain; and to determine whether these associations differ between those born with low or full birthweight.

METHODS

The cross-sectional associations between the lifetime prevalence of back pain and anthropometric measures (birthweight, weight gain and current BMI) among 2754 adult twins were investigated in three stages: total sample; within-pair case-control for monozygotic and dizygotic twins together; and within-pair case-control analysis separated by dizygotic and monozygotic. Results were expressed as odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Birthweight was not associated with back pain (OR 0.99; 95% CI 0.99-1.00), but a weak association was found between weight gain (OR 1.01; CI 1.00-1.01) or current BMI (OR 1.02; 95% CI 1.00-1.05) and back pain in the total sample analysis. These associations did not remain significant after adjusting for genetics. The associations did not differ between those whose were born with low or full birthweight.

CONCLUSION

Birthweight was not associated with prevalence of back pain in adulthood. Weight gain and current BMI were weakly associated with back pain prevalence in the total sample analysis but did not differ between those born with low or full birthweight. However, the small-magnitude association only just achieved significance and appeared to be confounded by genetics and the early shared environment. Our results suggest that a direct link between these predictors and back pain in adults is unlikely. These slides can be retrieved under Electronic Supplementary Material.

The association between body fat and musculoskeletal pain: a systematic review and meta-analysis

BACKGROUND

Obesity and musculoskeletal pain are strongly related, but there is emerging evidence that body fat, not body weight, may be a better indicator of risk. There is, therefore, a need to determine if body fat is associated with musculoskeletal pain as it may improve management strategies. The aim of this systematic review was to investigate the association between body fat and musculoskeletal pain.

METHODS

Seven electronic databases were searched from inception to 8th January 2018. Cross-sectional and longitudinal studies investigating the association between measures of body fat and musculoskeletal pain were included. All included articles were assessed for methodological rigour using the Epidemiology Appraisal Instrument. Standardised mean differences (SMDs) and effect estimates were pooled for meta-analysis.

RESULTS

A total of 10,221 citations were identified through the database searching, which after abstract and full-text review, yielded 28 unique articles. Fourteen studies were included in the meta-analyses, which found significant cross-sectional associations between total body fat mass and widespread pain (SMD 0.49, 95% CI 0.37-0.61, p < 0.001). Individuals with low-back pain and knee pain had a higher body fat percentage than asymptomatic controls (SMD 0.34, 95% CI 0.17-0.52, p < 0.001 and SMD 0.18, 95% CI 0.05-0.32, p = 0.009, respectively). Fat mass index was significantly, albeit weakly, associated with foot pain (SMD 0.05, 95% CI 0.03-0.06, p < 0.001). Longitudinal studies (n = 8) were unsuitable for meta-analysis, but were largely indicative of elevated body fat increasing the risk of incident and worsening joint pain. There was conflicting evidence for an association between body fat percentage and incident low-back pain (3 studies, follow-up 4-20 years). Increasing knee pain (1 study) and incident foot pain (2 studies) were positively associated with body fat percentage and fat mass index. The percentage of items in the EAI graded as 'yes' for each study ranged from 23 to 85%, indicating variable methodological quality of the included studies.

CONCLUSIONS

This systematic review and meta-analysis identified positive cross-sectional associations between increased body fat and widespread and single-site joint pain in the low-back, knee and foot. Longitudinal studies suggest elevated body fat may infer increased risk of incident and worsening joint pain, although further high-quality studies are required.

Twin studies for the prognosis, prevention and treatment of musculoskeletal conditions

BACKGROUND

Musculoskeletal conditions are highly prevalent in our ageing society and are therefore incurring substantial increases in population levels of years lived with disability (YLD). An evidence-based approach to the prognosis, prevention, and treatment of those disorders can allow an overall improvement in the quality of life of patients, while also softening the burden on national health care systems.

METHODS

In this Masterclass article, we provide an overview of the most relevant twin study designs, their advantages, limitations and major contributions to the investigation of traits related to the domain of musculoskeletal physical therapy.

CONCLUSIONS

Twin studies can be an important scientific tool to address issues related to musculoskeletal conditions. They allow researchers to understand how genes and environment combine to influence human health and disease. Twin registries and international collaboration through existing networks can provide resources for achieving large sample sizes and access to expertise in study design and analysis of twin data.

Changes of Metabolic Disorders Associated Peripheral Cytokine/Adipokine Traffic in Non-Obese Chronic Back Patients Responsive to Burst Spinal Cord Stimulation

OBJECTIVES

In our previous study, anti-inflammatory IL-10 serum levels were significantly elevated after burst spinal cord stimulation (SCS) in back pain patients and correlated with pain intensity. This current study extended cytokine analysis including metabolic-associated adipokine/cytokine serum assessment in chronic back pain patients with co-existing metabolic disorders such as diabetes, hypertension, and cardiovascular diseases.

METHODS

At baseline and after three months of burst SCS treatment, leptin (LP), adiponectin (AN), and ghrelin (GH) were recorded in non-/pre-obese chronic back pain patients with co-existing metabolic disorders and compared to age-/gender-matched healthy controls (HC).

RESULTS

Mean BMI was 22 ± 0.81 kg/m² in 12 (five male/seven female) participants with diabetes in 6/12 (50%), hypertension in 9 (75%), and CVD in five patients (42%). Pre- and post-SCS LP levels were significantly higher compared to healthy controls: pre-SCS, 30567 (12,996-58,821) vs. HC, 7952 (4932-12,583) pg/mL, p = 0.029; post-SCS, 18,890 (7140-44,719) vs. HC, 7952 (4932-12,583) pg/mL, p = 0.035. Pre- and post-SCS changes of GH (p = 0.18) and AN (p = 0.8) did not differ significantly. GH serum levels correlated with AN (Spearman r = 0.5; p = 0.012; 95 CI 0.11 to -0.76) and AN levels were significantly correlated with higher age (Pearson correlation r = 0.8; p = 0.002; 95 CI 0.41-0.94) at baseline.

CONCLUSIONS

This study determined serum changes of metabolic-associated cytokines/adipokines in non-obese chronic back pain patients responsive to burst SCS suggesting that neuroinflammation assessment may consider pain-associated mood, cognition, sleep, and metabolic state.

Epidemiology of Back Pain in Young and Middle-Aged Adults: A Longitudinal Population Cohort Survey From Age 27-50 Years

BACKGROUND

Back pain is extremely common and a huge burden for both individuals and health care services.

OBJECTIVE

The aim was to determine the prevalence and incidence of lumbar and cervical back pain over 23 years and to quantify associations with concomitant disorders.

METHODS

Data on lumbar and cervical back pain, and mental disorders from the Zurich study, collected between 1986 (age men: 27/women: 28 years) and 2008 (age 49/50) were analyzed. Epidemiological parameters were representative rates for the general population. Associations were quantified by odds ratios (ORs).

RESULTS

Of 499 subjects, 68.9% ever experienced lumbar pain and 60.7% ever experienced cervical back pain; the 23-year prevalences were 66.9% and 54.9% and the 23-year incidences 52.3% and 48.9% for lumbar and cervical back pain, respectively. Annual prevalences varied between 28.4% and 47.2% for lumbar and 18.3% and 54.7% for cervical back pain; the corresponding annual incidences varied by 5.8-13.3% (lumbar) and 7.8-12.6% (cervical). Lumbar back pain was significantly associated with cardiovascular disease (OR = 4.58), obesity (OR = 3.99), asthma spectrum (OR = 5.76), tranquillizer dependence (OR = 5.84), and other comorbidities (ORs = 1.47-3.27). Significant associations with cervical back pain were observed for specific phobia (OR = 5.10), panic attacks (OR = 4.79), and other comorbidities (ORs = 1.61-2.62).

CONCLUSIONS

This study contributes to the refinement of epidemiological data on lumbar and cervical back pain. Some associations with treatable disorders were high, which may offer hope for the indirect management of lumbar and cervical back pain.