The association between smoking and low back pain: a meta-analysis

Longitudinal Associations of Family Relationship Quality With Chronic Pain Incidence and Persistence Among Aging African Americans

OBJECTIVES

This study examines how family relationships convey risk or resilience for pain outcomes for aging African Americans, and to replicate and extend analyses across 2 nationally representative studies of aging health.

METHODS

African American participants in Midlife in the United States (MIDUS, N = 755) and the Health and Retirement Study (HRS, N = 2,585) self-reported chronic pain status at 2006 waves and then again 10 years later. Logistic regression was used to estimate the odds of pain incidence and persistence explained by family, intimate partner, and parent-child strain and support, as well as average support and average strain across relationships.

RESULTS

On average, MIDUS participants were younger (M = 52.35, SD = 12.06; 62.1% female) than HRS (M = 66.65, SD = 10.92; 63.7% female). Family support and average support were linked to decreased odds of pain incidence in MIDUS, but only when tested without accounting for strain, whereas parent-child strain was a risk factor for pain incidence in HRS, as was average strain. Family support protected against pain persistence in MIDUS, whereas average support was linked to reduced odds of pain persisting in HRS.

DISCUSSION

Chronic pain outcomes are worse for African Americans for a number of reasons, but parent-child strain may contribute to the risk of new pain developing over time for older adults. Conversely, family support may offer a protective benefit for pain incidence and persistence among aging African Americans. Findings implicate family relationships as a potential target of pain management interventions.

Is device-measured physical activity associated with musculoskeletal disorders among young adult Finnish men?

Background

Musculoskeletal (MSK) disorders represent a significant burden to society and can be unpleasant for the affected individuals. Physical activity (PA) can prevent MSK disorders while conferring other health benefits. The present study aimed to investigate associations between device-measured PA and perceived MSK disorders among young adult men.

Methods

PA at different intensity levels, standing, and sedentary behavior were measured with a hip-worn accelerometer in a cohort of 422 young adult Finnish men aged 26 years on average. The incidences of three common MSK disorders (viz., knee pain, lumbar radicular pain, and lumbago pain) during the last month were inquired by a questionnaire. Binary logistic regression was used to examine the associations between the MSK outcomes and explanatory PA variables (PA times at different intensity levels, standing, and sedentary times). The models were controlled for age, education, smoking, BMI, and maximal oxygen uptake.

Results

PA, standing, and sedentary times were not significantly associated with the incidence of perceived MSK pain during the last month, except for lumbago pain. Lumbago pain was slightly more probable if the time spent in light PA increased, even after controlling for potential confounding factors, including moderate-to-vigorous PA, with an odds ratio (OR) of 1.07 (95% CI: 1.02-1.14). Sedentary time showed an opposite association, with an OR of 0.98 (95% CI: 0.96-1.00).

Conclusions

There were neither positive nor negative clinically meaningful associations between PA and recent MSK disorders among young adult men. The result is surprising and requires further confirmation.

Workplace Psychosocial Factors, Work Organization, and Physical Exertion as Risk Factors for Low Back Pain Among US Workers: Data From the 2015 National Health Interview Survey

OBJECTIVE

To evaluate the association between workplace psychosocial, organization, and physical risk factors with low back pain (LBP) among US workers.

METHODS

2015 National Health Interview Survey data were analyzed to calculate the prevalence rates and prevalence ratios for LBP across levels of workplace psychosocial and organizational risk factors among 17,464 US adult workers who worked ≥20 hours per week. Results were also stratified by workplace physical exertion.

RESULTS

The adjusted prevalence rates of LBP were significantly elevated for workers reporting high job demand, low job control, work-family imbalance, bullying, job insecurity, working alternate shifts, and physical exertion. Job control and nonstandard shifts were significantly associated with LBP only among those who reported low/no physical exertion.

CONCLUSIONS

LBP prevalence was associated with select workplace psychosocial and organization risk factors. Stratification by physical exertion modified multiple associations.

Management and Nursing Approaches to Low Back Pain: Investigating the Causal Association with Lifestyle-Related Risk Factors

BACKGROUND

Notwithstanding a plethora of observational studies, the causal implications of obesity, encompassing both body mass index (BMI) and waist circumference (WC), as well as type 2 diabetes (T2D), and lifestyle factors, in relation to the vulnerability to low back pain (LBP), remain enigmatic.

AIMS

This study was designed to investigate the related causal associations DESIGN: A two-sample Mendelian randomization (MR) analysis.

SETTINGS

By utilizing genetic variants associated with pertinent factors gleaned from genome-wide association studies (GWASs), We extracted independent genetic variants about exposures such as BMI, WC, T2D, smoking, alcohol consumption, and coffee intake from published GWASs, ensuring their genome-wide significance.

PARTICIPANTS/SUBJECTS

The GWASs were selected from the most up-to-date and largest publicly accessible databases.

METHODS

The summary data concerning LBP emanated from a GWAS of European cases and controls, which was based on the esteemed MRC-IEU (Medical Research Council Integrative Epidemiology Unit) consortium.

RESULTS

Heightened body mass index and waist circumference exhibited odds ratios of 1.003 (95% confidence interval [CI] = 1.002-1.004, p < 0.001) and 1.003 (95% CI = 1.002-1.004, p < 0.001) for LBP, respectively, per each standard deviation (SD) increase. As for smoking initiation and every SD increase in the frequency of alcohol intake, the odds ratios were 1.002 (95% CI = 1.001-1.003, p = 0.003) and 1.002 (95% CI = 1.000-1.003, p = 0.011), respectively, for LBP. Conversely, an increased log odds ratio for T2D, and prevalence of coffee intake, divulged no discernible causal effects on the risk of LBP.

CONCLUSION

This study provides suggestive evidence to support the causal involvement of obesity, smoking, and the frequency of alcohol intake in the development of LBP, which suggests that implementing measures to mitigate these risk factors may aid in preventing LBP.

Predictors of musculoskeletal disorders among special education teachers in Sabah, Malaysia

Special education teachers encounter considerable occupational challenges, yet there is limited information concerning musculoskeletal disorders (MSD) within this group. Therefore, this study aimed to address this gap by determining the prevalence of MSD, investigating associated factors of MSD, and identifying predictors of MSD among special education teachers. A cross-sectional study was conducted among special education teachers in Kota Kinabalu and Penampang, Sabah. Data were collected through self-administered questionnaires and musculoskeletal fitness assessments. Chi-square tests and independent t-tests were utilized to determine factors associated with MSD, while multiple logistic regression was performed to develop a comprehensive predictive model for MSD, which was then validated and tested for model fitness. A total of 122 individuals participated in the study, yielding a response rate of 95 %. The findings revealed a high prevalence of MSD (77.9 %) among special education teachers, with the lower back, shoulder, neck, knee, upper back, and foot being the most affected regions. The multivariable regression model identified several predictors of MSD, including marital status (adjusted odds ratio [aOR] = 4.78, 95 % confidence interval [CI] = 1.49-15.40), body fat percentage (aOR = 1.06, 95 % CI = 1.00-1.12), teaching in prolonged standing for few days a week (aOR = 3.20, 95 % CI = 0.99-10.29) or every day (aOR = 6.20, 95 % CI = 1.44-26.70), mindfulness (aOR = 0.47, 95 % CI = 0.22-0.98), and back extensor strength (aOR = 5.86, 95 % CI = 1.92-17.92). This study highlights the necessity of implementing interventions focusing on the ergonomic, psychological, and musculoskeletal fitness components to mitigate the prevalence of MSD and improve the overall well-being of special education teachers.

Effects of pain education on disability, pain, quality of life, and self-efficacy in chronic low back pain: A randomized controlled trial

BACKGROUND

Low back pain stands as a prevalent contributor to pain-related disability on a global scale. In addressing chronic low back pain (CLBP), there is a growing emphasis on incorporating psychological strategies into the management process. Among these, pain education interventions strive to reshape pain beliefs and mitigate the perceived threat of pain. This randomized controlled trial sought to assess the effects of pain education on various aspects, including pain levels, disability, quality of life, self-efficacy, and prognostic characteristics in individuals grappling with CLBP.

METHODS

The clinical trial, retrospectively registered with the Clinical Trials Registry of India (CTRI/2021/08/035963), employed a two-arm parallel randomized design. Ninety-two participants with CLBP were randomly assigned to either the standard physiotherapy care with a pain education program or the control group. Both groups underwent a 6-week intervention. Assessment of pain intensity (using NPRS), disability (using RMDQ), self-efficacy (using the general self-efficacy scale), and well-being (using WHO 5I) occurred both before and after the 6-week study intervention.

FINDINGS

Post-intervention score comparisons between the groups revealed that the pain education intervention led to a significant reduction in disability compared to the usual standard care at 6 weeks (mean difference 8.2, p < 0.001, effect size Cohen d = 0.75), a decrease in pain intensity (mean difference 3.5, p < 0.001, effect size Cohen d = 0.82), and an improvement in the well-being index (mean difference 13.7, p < 0.001, effect size Cohen d = 0.58).

CONCLUSION

The findings suggest that integrating a pain education program enhances the therapeutic benefits of standard physiotherapy care for individuals dealing with chronic LBP. In conclusion, the clinical benefits of pain education become apparent when delivered in conjunction with standard care physiotherapy during the management of chronic low back pain.

Associations between smoking and pain in early recovery in residential substance use treatment-seekers

INTRODUCTION

A growing literature indicates bidirectional associations between pain and tobacco use. Cigarette smokers are at increased risk for chronic pain, and observational and experimental studies indicate that pain increases motivation to smoke. Tobacco use disorder frequently co-occurs with other substance use disorders, which are also associated with chronic pain vulnerability. Despite evidence that pain significantly predicts smoking and relapse, associations between smoking history/trajectory and changes in pain over the course of treatment have not been characterized. The objective of the study was to determine the association between in-treatment smoking trajectory, pack-years (i.e., number of cigarette packs smoked per day multiplied by smoking duration), pain-related interference in daily activities, and pain intensity over the course of residential treatment.

METHODS

In this study, 280 adult smokers in a residential SUD treatment center in North Central Florida completed questionnaires assessing cigarette use, pain intensity, and pain interference at treatment entry and discharge (Mean = 80.3 days, SD = 25.6). Most participants were diagnosed with alcohol use disorder (66.1 %). Opioid (27.9 %) and cannabis use disorders (29.6 %) were also common. Participants were grouped by whether their smoking increased (n = 36), decreased (n = 46), or stayed the same (n = 133) from entry to discharge.

RESULTS

Analyses indicated a positive association between pack-years and pain intensity at both baseline (r = 0.185, p = 0.018) and discharge (r = 0.184, p = 0.019). Smoking trajectory was associated with pack-years, with those decreasing smoking having greater pack-years than those sustaining or increasing use [F(2,136) = 8.62, p < 0.01, η2p = 0.114]. Mixed general linear models indicated pain intensity [F(1,274) = 44.15, p < 0.0001, η2p = 0.138] and interference in day-to-day activities [F(1,276) = 31.79, p < 0.0001, η2p = 0.103] decreased significantly over time. However, there was no main effect of smoking trajectory on pain intensity [F(2,212) = 2.051, p = 0.131, η2p = 0.019] or of smoking trajectory by time interaction [F(2, 212) = 1.228, p = 0.295, η2p = 0.011].

CONCLUSIONS

Overall, findings provide evidence that smoking behavior influences pain within the context of residential substance use treatment. Given that pain is associated with urge to use substances and risk of return to use, more consistent and rigorous assessment of pain and proactive pain management is likely to enhance substance use treatment outcomes among people who smoke.

Work-related diseases and risk factors associated with work-related musculoskeletal disorders among unionized metal industry workers: a cross-sectional study

Objectives. This study aimed to determine the prevalence of work-related diseases (WRDs) and work-related musculoskeletal disorders (WR-MSDs), as well as investigate WR-MSD-associated risk factors, among metal industry workers in Turkey. Methods. The cross-sectional study was conducted with 1374 members of the Birleşik Metal İş Union from 121 companies. Data were collected using a self-administered 30-item questionnaire. Results. The survey response rate was 81.4% (1374/1686). Almost one out of every six workers (14.8%) stated that they had been diagnosed with a WRD, 3.6% reported that they had been diagnosed with an occupational disease and 38.6% of them indicated that they had suffered an occupational accident (OA) at least once. The prevalence of WR-MSDs was 10.7%, of work-related lung diseases was 1.8% and of occupational hearing loss was 0.6%. Quitting smoking, smoking, OA, heavy lifting, time pressure and working in the automotive industry were all associated with WR-MSDs. Conclusions. Interventions aimed at reducing musculoskeletal disorders (MSDs) should focus on smoking cessation, training workers in proper techniques and equipment for lifting and pushing/pulling heavy loads, preventing OAs and injuries, and reducing the time pressure in the workplace in the metal industry.

Global, Regional, and National Change Patterns in the Incidence of Low Back Pain From 1990 to 2019 and Its Predicted Level in the Next Decade

Objectives: To analyze and describe the spatiotemporal trends of Low back pain (LBP) burdens from 1990 to 2019 and anticipate the following decade's incidence. Methods: Using data from the Global Burden of Disease (GBD) 2019 Study, we described net drifts, local drifts, age effects, and period cohort effects in incidence and forecasted incidence rates and cases by sex from 2020 to 2029 using the Nordpred R package. Results: LBP remained the leading cause of the musculoskeletal disease burden globally and across all socio-demographic index (SDI) regions. China is the top country. For recent periods, high-SDI countries faced unfavorable or worsening risks. The relative risk of incidence showed improving trends over time and in successively younger birth cohorts amongst low-middle-, middle- and high-middle-SDI countries. Additionally, the age-standardized incidence rates (ASIR) of LBP in both sexes globally showed a decreasing trend, but the incident cases would increase from 223 to 253 million overall in the next decade. Conclusion: As the population ages, incident cases will rise but ASIR will fall. To minimise LBP, public awareness and disease prevention and control are needed.

Time-Dependent Prediction Models for Individual Prognosis of Chronic Postsurgical Pain following Knee Replacement Based on an Extensive Multivariable Data Set

(1) Background: Clinically useful prediction models for chronic postsurgical pain (CPSP) in knee replacement (TKA) are lacking. (2) Methods: In our prospective, multicenter study, a wide-ranging set of 91 variables was collected from 933 TKA patients at eight time points up to one year after surgery. Based on this extensive data pool, simple and complex prediction models were calculated for the preoperative time point and for 6 months after surgery, using least absolute shrinkage and selection operator (LASSO) 1se and LASSO min, respectively. (3) Results: Using preoperative data only, LASSO 1se selected age, the Revised Life Orientation Test on pessimism, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)-subscore pain and the Timed "Up and Go" Test for prediction, resulting in an area under the curve (AUC) of 0.617 and a Brier score of 0.201, expressing low predictive power only. Using data up to 6 months after surgery, LASSO 1se included preoperative Patient Health Questionnaire-4, Knee Injury and Osteoarthritis Outcome Score (KOOS)-subscore pain (pain) 3 months after surgery (month), WOMAC pain 3 and 6 months, KOOS subscore symptoms 6 months, KOOS subscore sport 6 months and KOOS subscore Quality of Life 6 months. This improved the predictive power to an intermediate one (AUC 0.755, Brier score 0.168). More complex models computed using LASSO min did little to further improve the strength of prediction. (4) Conclusions: Even using multiple variables and complex calculation methods, the possibility of individual prediction of CPSP after TKA remains limited.

The joint association of insomnia disorder and lifestyle on the risk of activity-limiting spinal pain: the HUNT Study

OBJECTIVES

To investigate whether the combination of multiple healthy lifestyle factors modify the well-established association between insomnia disorder and risk of activity-limiting spinal pain.

METHODS

We conducted a prospective study of 10,228 individuals who participated in two surveys over ∼11 years and were free of chronic pain in the neck, upper back, and lower back at baseline. Adjusted risk ratios (RRs) were calculated for the risk of activity-limiting chronic spinal pain (i.e., pain that impairs daily activities at work or leisure time) at follow-up associated with the joint association of insomnia disorder and the combination of five lifestyle factors (body mass index, leisure time physical activity, alcohol consumption, diet, and smoking) at baseline.

RESULTS

Our data indicate an additive interaction between insomnia disorder and lifestyle on risk of activity-limiting spinal pain, i.e., compared with participants without insomnia disorder and the best lifestyle score, participants with insomnia disorder and the worst lifestyle score had a RR of activity-limiting spinal pain of 3.57 (95 % CI: 2.65-4.80); participants with insomnia disorder and the best lifestyle score had a RR of 1.56 (95 % CI: 0.97-2.50); and those without insomnia disorder and the worst lifestyle score had a RR of 1.32 (95 % CI: 1.12-1.55).

CONCLUSIONS

Poor lifestyle behaviour amplifies the adverse effect of insomnia disorder on the risk of activity-limiting chronic spinal pain.

Causations between obesity, diabetes, lifestyle factors and the risk of low back pain

BACKGROUND

Despite numerous observational studies, the causal relationship between obesity-measured by body mass index (BMI) and waist circumference (WC)-as well as type 2 diabetes (T2D), lifestyle habits, and susceptibility to low back pain (LBP) remains obscure.

METHODS

This investigation employed two-sample Mendelian randomization (MR) analysis to explore causality, using genetic variants linked to relevant factors from genome-wide association studies (GWASs). Specifically, we selected independent genetic variants related to BMI, WC, T2D, smoking, alcohol consumption, and coffee intake from established GWASs, all of which demonstrated genome-wide significance. The comparative data for LBP were derived from a GWAS involving European subjects, under the auspices of the renowned MRC-IEU (Medical Research Council Integrative Epidemiology Unit) consortium.

RESULTS

Elevated BMI and WC were associated with odds ratios of 1.002 (95% confidence interval [CI] = 1.001-1.004, p < 0.001) and 1.003 (95% CI = 1.002-1.004, p < 0.001) for LBP per standard deviation (SD) increase, respectively. Regarding smoking initiation and coffee consumption, the odds ratios stood at 1.002 (95% CI = 1.001-1.004, p = 0.001) and 1.004 (95% CI = 1.001-1.008, p = 0.034) for LBP, respectively. However, an augmented log odds ratio for T2D and each SD rise in alcohol consumption frequency revealed no significant causal impact on LBP risk.

CONCLUSION

Our findings indicate a potential causal link between obesity, smoking, and coffee intake in the genesis of LBP, suggesting that mitigating these factors could contribute to LBP prevention.

Strong Association of Depression and Anxiety With the Presence of Back Pain While Impact of Spinal Imaging Findings is Limited: Analysis of an MRI Cohort Study

Development of back pain is multifactorial, and it is not well understood which factors are the main drivers of the disease. We therefore applied a machine-learning approach to an existing large cohort study data set and sought to identify and rank the most important contributors to the presence of back pain amongst the documented parameters of the cohort. Data from 399 participants in the KORA-MRI (Cooperative health research in the region Augsburg-magnetic resonance imaging) (Cooperative Health Research in the Region Augsburg) study was analyzed. The data set included MRI images of the whole body, including the spine, metabolic, sociodemographic, anthropometric, and cardiovascular data. The presence of back pain was one of the documented items in this data set. Applying a machine-learning approach to this preexisting data set, we sought to identify the variables that were most strongly associated with back pain. Mediation analysis was performed to evaluate the underlying mechanisms of the identified associations. We found that depression and anxiety were the 2 most selected predictors for back pain in our model. Additionally, body mass index, spinal canal width and disc generation, medium and heavy physical work as well as cardiovascular factors were among the top 10 most selected predictors. Using mediation analysis, we found that the effects of anxiety and depression on the presence of back pain were mainly direct effects that were not mediated by spinal imaging. In summary, we found that psychological factors were the most important predictors of back pain in our cohort. This supports the notion that back pain should be treated in a personalized multidimensional framework. PERSPECTIVE: This article presents a wholistic approach to the problem of back pain. We found that depression and anxiety were the top predictors of back pain in our cohort. This strengthens the case for a multidimensional treatment approach to back pain, possibly with a special emphasis on psychological factors.

Systematic replication of smoking disease associations using survey responses and EHR data in the All of Us Research Program

OBJECTIVE

The All of Us Research Program (All of Us) aims to recruit over a million participants to further precision medicine. Essential to the verification of biobanks is a replication of known associations to establish validity. Here, we evaluated how well All of Us data replicated known cigarette smoking associations.

MATERIALS AND METHODS

We defined smoking exposure as follows: (1) an EHR Smoking exposure that used International Classification of Disease codes; (2) participant provided information (PPI) Ever Smoking; and, (3) PPI Current Smoking, both from the lifestyle survey. We performed a phenome-wide association study (PheWAS) for each smoking exposure measurement type. For each, we compared the effect sizes derived from the PheWAS to published meta-analyses that studied cigarette smoking from PubMed. We defined two levels of replication of meta-analyses: (1) nominally replicated: which required agreement of direction of effect size, and (2) fully replicated: which required overlap of confidence intervals.

RESULTS

PheWASes with EHR Smoking, PPI Ever Smoking, and PPI Current Smoking revealed 736, 492, and 639 phenome-wide significant associations, respectively. We identified 165 meta-analyses representing 99 distinct phenotypes that could be matched to EHR phenotypes. At P < .05, 74 were nominally replicated and 55 were fully replicated. At P < 2.68 × 10-5 (Bonferroni threshold), 58 were nominally replicated and 40 were fully replicated.

DISCUSSION

Most phenotypes found in published meta-analyses associated with smoking were nominally replicated in All of Us. Both survey and EHR definitions for smoking produced similar results.

CONCLUSION

This study demonstrated the feasibility of studying common exposures using All of Us data.

Association between smoking and incident back pain: A prospective cohort study with 438 510 participants

Background

Although smoking is a known potential contributor to back pain, there is still a lack of quantitative studies on the effects of different doses on back pain (BP) occurrence, including a lack of a longitudinal cohorts. To address this gap, we aimed to investigate the association between various smoking-related exposures and back pain incidence to advance global efforts toward smoking cessation and guide primary prevention of BP.

Methods

In this prospective cohort study, we retrieved data on 438 510 patients from the UK Biobank who were free of back pain and who were recruited in 2006-2010, and followed them up from baseline through 1 April 2022. We extracted data on smoking-related exposures, including smoking status (SS), number of cigarettes smoked daily (CPD), and pack-years of own smoking (PY) and examined back pain incidence as an outcome. We used a Cox proportional hazard model adjusted for several covariates, multiple imputation methods, and population attribution fraction.

Results

During the median follow-up of 12.98 years, 31 467 participants developed BP, with incidence rates in former and current smokers of 1.13 (95% confidence interval (CI) = 1.10-1.16, P < 0.000) and 1.50 (95% CI = 1.45-1.56, P < 0.000), respectively. The hazard ratios (HRs) of participants who smoked more than 30 CPD and those with more than 30 PY were 1.45 (95% CI = 1.36-1.55, P < 0.000) and 1.45 (95% CI = 1.40-1.50, P < 0.000), respectively. Relative to male, female smokers were at more risk of developing BP. Not smoking, quitting smoking, and reducing CPD and PY could lower the BP risk by 7.8%, 5.4%, 9.8%, and 18.0%, respectively.

Conclusions

Ever smoking, higher cigarette consumption daily, and increased smoking intensity were associated with an increased BP risk. This association was stronger in female smokers. Not smoking, smoking cessation, and reducing smoking volume and intensity were effective measures to prevent BP occurrence.

The burden of neck pain among adults aged 70 years and older in Iran, 1990-2019

Background

Neck pain is a complex musculoskeletal disorder that can result in substantial morbidity. The present article presents the neck pain burden in Iranians who were at least 70 years old, from 1990 to 2019, by sex, age group, and province.

Methods

Publicly available information on the prevalence, incidence, and years lived with disability (YLD) caused by neck pain was extracted from the Global Burden of Disease study 2019. The estimates were all provided as counts and age-standardized rates (per 100,000), and included 95% uncertainty intervals.

Results

The point prevalence of neck pain in 2019 was 8710.6, while the incidence rate was 1334.7 per 100,000 population. That same year, there were number of 27.8 thousand YLDs and an YLD rate of 801.7 per 100,000. The prevalence, incidence, and YLD rates did not change substantially over the measurement period (1990-2019). The highest YLD rate was found in Tehran (960.9 per 100,000), while Kohgiluyeh and Boyer-Ahmad had the lowest (730.5 per 100,000). Females had slightly higher prevalent cases, incident cases, and YLDs, as well as their corresponding rates in 2019. In 2019, the number of prevalent cases, incident cases, and YLDs peaked in the 70-74 age group, for both sexes, and in all cases they reduced with age. In both 1990 and 2019, Iran had a higher YLD rate than that found among elderly adults in the Middle East and North Africa region.

Conclusions

The burden of neck pain in Iran has decreased slightly over the last three decades, but it still imposes a substantial burden and is higher than that found in the rest of the region. Therefore, preventive programs should be initiated at a young age to reduce the attributable burden later in life.

Assessing the impacts of smoking cessation and resumption on back pain risk in later life

BACKGROUND

This study aimed to assess the impacts of smoking cessation and resumption over 4 years on the risk of back pain at the 6-year follow-up among older adults in England.

METHODS

We analysed 6467 men and women aged ≥50 years in the English Longitudinal Study of Aging. Self-reported smoking status, assessed in waves 4 (2008-2009) and 6 (2012-2013), was used as exposure for the study, whereas self-reported back pain of moderate or severe intensity, assessed in wave 7 (2014-2015), was used as the outcome. A targeted minimum loss-based estimator was used with longitudinal modified treatment policies to adjust for baseline and time-varying covariates.

RESULTS

Regarding the estimation of the effects of changes in smoking status on the risk of back pain, during the follow-up, individuals who resumed smoking within 4 years had a higher risk of back pain than those who avoided smoking for over 4 years, and the relative risk (RR) (95% confidence interval [CI]) was 1.536 (1.214-1.942). Regarding the estimation of effects of smoking cessation on the risk of back pain, smoking cessation over 4 years was associated with a significantly lower risk of back pain, as indicated by the originally observed data, and the RR (95% CI) was 0.955 (0.912-0.999).

CONCLUSIONS

Older adults who avoided smoking for over 4 years had a lower risk of back pain. However, those who resumed smoking within 4 years had a higher risk of back pain.

SIGNIFICANCE

Older adults who avoided smoking for over 4 years had a lower risk of back pain. However, those who resumed smoking within 4 years had a higher risk of back pain. Our study data suggest the importance of maintaining smoking cessation to reduce the risk of back pain in the older population.

The Use of Pain Severity and Its Impact as a Predictor for MRI Findings: A Cross-Sectional Study in Ta'if, Saudi Arabia

Background Low back pain (LBP) is common and considerably impacts daily lives across all age groups. MRI is not frequently used as a first-line investigation for patients presenting with LBP, except in the presence of red-flag symptoms. This study aimed to use pain severity and its impact as a predictor for MRI findings to help physicians decide whether a patient needs an MRI. Methods This cross-sectional study was conducted at the outpatient clinic of the neurosurgery department. The questionnaire included demographic data of the patients, red-flag symptoms, and the Dallas Pain Questionnaire (DPQ). The primary physician then determines whether the patient should have an MRI appointment. Results The study included 100 patients with LBP, of which 71 had chronic LBP (CLBP). Out of these 71, an MRI was requested for 62, but only 26 had findings related to LBP. Regarding the impact of CLBP on daily activities as measured by the DPQ, there was a significant association between those whose CLBP affected their daily activities and the decision to request an MRI. However, no significant statistical association was found between the three other parameters of the DPQ and the primary physician's decision to request an MRI. Conclusion Concerning the use of the DPQ questionnaire to predict MRI findings in patients with CLBP, the study indicates that significant pain impact on the DPQ does not necessarily correlate with MRI findings related to LBP. This suggests that the DPQ evaluation tool has no advantage over a physician's clinical judgment.

Low Back Pain in Medical Students and Professors During the Pandemic: Retrospective Cohort Study

Objective  This study aimed to determine the prevalence of low back pain before and during the pandemic, comparing both periods. Methods  A questionnaire was administered, containing questions about the presence of low back pain, sociodemographic characteristics and environmental factors that could be related to such pain. Results  Among the 978 responses obtained, the prevalence of low back pain during the pandemic was 69.94%, which represented a significant increase over values from the pre-pandemic period (57.37%). A high prevalence of low back pain was found between all groups, especially among women. Some factors were associated with the incidence of low back pain, such as having previously diagnosed spinal problems and sedentary lifestyle. Conclusions  The prevalence of low back pain increased significantly during the pandemic in the studied groups.

Evidence of causal effects of blood pressure on back pain and back pain on type II diabetes provided by a bidirectional Mendelian randomization study

BACKGROUND CONTEXT

Cardiovascular risk factors (hypertension, dyslipidemia, and type II diabetes) have been proposed as risk factors for back pain. However, few longitudinal studies have found significant associations between cardiovascular risk factors and back pain, and these may be explained by confounding or reverse causation.

PURPOSE

To examine potential causal effects of cardiovascular risk factors on back pain, and vice versa.

STUDY DESIGN

Bidirectional Mendelian randomization (MR) study.

PATIENT SAMPLES

Genome-wide association studies (GWAS) with sample sizes between 173,082 and 1,028,947 participants.

OUTCOME MEASURES

Outcomes included (1) back pain associated with health care use (BP-HC) in the forward MR; and (2) seven cardiovascular phenotypes in the reverse MR, including 2 measurements used for the evaluation of hypertension (diastolic blood pressure and systolic blood pressure), 4 phenotypes related to dyslipidemia (LDL cholesterol, HDL cholesterol, total cholesterol, and triglycerides), and type II diabetes.

METHODS

We used summary statistics from large, publicly available GWAS for BP-HC and the 7 cardiovascular phenotypes to obtain genetic instrumental variables. We examined MR evidence for causal associations using inverse-variance weighted (IVW) analysis, Causal Analysis Using Summary Effect (CAUSE), and sensitivity analyses.

RESULTS

In forward MR analyses of seven cardiovascular phenotypes, diastolic blood pressure was associated with BP-HC across all analyses (IVW estimate: OR = 1.10 per 10.5 mm Hg increase [1.04-1.17], p-value = .001), and significant associations of systolic blood pressure with BP-HC were also found (IVW estimate: OR = 1.09 per 19.3 mm Hg increase [1.04-1.15], p-value = .0006). In reverse MR analyses, only type II diabetes was associated with BP-HC across all analyses (IVW estimate: OR = 1.40 [1.13-1.73], p-value = .002).

CONCLUSIONS

These findings from analyses of large, population-based samples indicate that higher blood pressure increases the risk of BP-HC, and BP-HC itself increases the risk of type II diabetes.

Physical activity and education about physical activity for chronic musculoskeletal pain in children and adolescents

BACKGROUND

Chronic pain is a major health and socioeconomic burden, which is prevalent in children and adolescents. Among the most widely used interventions in children and adolescents are physical activity (including exercises) and education about physical activity.

OBJECTIVES

To evaluate the effectiveness of physical activity, education about physical activity, or both, compared with usual care (including waiting-list, and minimal interventions, such as advice, relaxation classes, or social group meetings) or active medical care in children and adolescents with chronic musculoskeletal pain.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, PsycINFO, PEDro, and LILACS from the date of their inception to October 2022. We also searched the reference lists of eligible papers, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared physical activity or education about physical activity, or both, with usual care (including waiting-list and minimal interventions) or active medical care, in children and adolescents with chronic musculoskeletal pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently determined the eligibility of the included studies. Our primary outcomes were pain intensity, disability, and adverse events. Our secondary outcomes were depression, anxiety, fear avoidance, quality of life, physical activity level, and caregiver distress. We extracted data at postintervention assessment, and long-term follow-up. Two review authors independently assessed risk of bias for each study, using the RoB 1. We assessed the overall certainty of the evidence using the GRADE approach. We reported continuous outcomes as mean differences, and determined clinically important differences from the literature, or 10% of the scale.

MAIN RESULTS

We included four studies (243 participants with juvenile idiopathic arthritis). We judged all included studies to be at unclear risk of selection bias, performance bias, and detection bias, and at high risk of attrition bias. We downgraded the certainty of the evidence for each outcome to very low due to serious or very serious study limitations, inconsistency, and imprecision. Physical activity compared with usual care Physical activity may slightly reduce pain intensity (0 to 100 scale; 0 = no pain) compared with usual care at postintervention (standardised mean difference (SMD) -0.45, 95% confidence interval (CI) -0.82 to -0.08; 2 studies, 118 participants; recalculated as a mean difference (MD) -12.19, 95% CI -21.99 to -2.38; I² = 0%; very low-certainty evidence). Physical activity may slightly improve disability (0 to 3 scale; 0 = no disability) compared with usual care at postintervention assessment (MD -0.37, 95% CI -0.56 to -0.19; I² = 0%; 3 studies, 170 participants; very low-certainty evidence). We found no clear evidence of a difference in quality of life (QoL; 0 to 100 scale; lower scores = better QoL) between physical activity and usual care at postintervention assessment (SMD -0.46, 95% CI -1.27 to 0.35; 4 studies, 201 participants; very low-certainty evidence; recalculated as MD -6.30, 95% CI -18.23 to 5.64; I² = 91%). None of the included studies measured adverse events, depression, or anxiety for this comparison. Physical activity compared with active medical care We found no studies that could be analysed in this comparison. Education about physical activity compared with usual care or active medical care We found no studies that could be analysed in this comparison. Physical activity and education about physical activity compared with usual care or active medical care We found no studies that could be analysed in this comparison.

AUTHORS' CONCLUSIONS

We are unable to confidently state whether interventions based on physical activity and education about physical activity are more effective than usual care for children and adolescents with chronic musculoskeletal pain. We found very low-certainty evidence that physical activity may reduce pain intensity and improve disability postintervention compared with usual care, for children and adolescents with juvenile idiopathic arthritis. We did not find any studies reporting educational interventions; it remains unknown how these interventions influence the outcomes in children and adolescents with chronic musculoskeletal pain. Treatment decisions should consider the current best evidence, the professional's experience, and the young person's preferences. Further randomised controlled trials in other common chronic musculoskeletal pain conditions, with high methodological quality, large sample size, and long-term follow-up are urgently needed.

Effects of a back school-based intervention on non-specific low back pain in adults: a randomized controlled trial

BACKGROUND

Non-specific low back pain is a common condition with significant global prevalence and socio-economic impact. Back School programs, which combine exercise and educational interventions, have been used to address back pain. This study aimed to investigate the effects of a Back School-based intervention on non-specific low back pain in adults. Secondary objectives included evaluating the impact of the program on disability, quality of life, and kinesiophobia.

METHODS

A randomized controlled trial was conducted involving 40 participants with non-specific low back pain, who were divided into two groups. The experimental group underwent an 8-week Back School-based program. The program comprised 14 practical sessions focusing on strengthening and flexibility exercises, along with two theoretical sessions covering anatomy and concepts related to a healthy lifestyle. The control group maintained their usual lifestyle. Assessment instruments included the Visual Analogue Scale, Roland Morris disability questionnaire, Short-Form Health Survey-36, and Tampa Scale of Kinesiophobia.

RESULTS

The experimental group showed significant improvements in the Visual Analogue Scale, Roland Morris disability questionnaire, physical components of the Short-Form Health Survey-36, and Tampa Scale of Kinesiophobia. However, there were no significant improvements in the psychosocial components of the Short-Form Health Survey-36. In contrast, the control group did not show significant results in any of the study variables.

CONCLUSIONS

The Back School-based program has positive effects on pain, low back disability, physical components of quality of life, and kinesiophobia in adults with non-specific low back pain. However, it does not appear to improve the participants' psychosocial components of quality of life. Healthcare professionals can consider implementing this program to help reduce the significant socio-economic impact of non-specific low back pain worldwide.

TRIAL REGISTRATION

NCT05391165 (registered prospectively in ClinicalTrials.gov: 25/05/2022).

Investigation of the Relevant Factors in the Complexity of Chronic Low Back Pain Patients With a Physiotherapy Prescription: A Network Analysis Approach Comparing Chronic Pain-Free Individuals and Chronic Patients

OBJECTIVE

Chronic low back pain (CLBP) is the leading cause of disability worldwide, and several factors have been proposed as potential causes or cofactors. The aim of this study was to explore their direct and indirect relations to understand CLBP and identify relevant rehabilitation targets.

METHODS

A total of 119 patients with CLBP and 117 chronic pain-free individuals were assessed. A network analysis approach was used to explore the complexity of CLBP by assessing the relations between pain intensity, disability, functionality (physical, social, and psychological), age, body mass index, and education level.

RESULTS

The network analysis revealed the independence of pain and disability related to CLBP from age, sex, and body mass index. Crucially, pain intensity and disability are directly and strongly connected in chronic pain-free individuals, but not in patients with CLBP. Psychosocial functioning is related to pain intensity and disability indirectly through the mediation of one's general health perception and perceived physical functionality.

CONCLUSION

Clinicians should pay more attention to perceived physical functionality and psychosocial factors as they are tightly linked to CLBP. Indeed, pain intensity seems a suboptimal rehabilitation target. This study suggests that a biopsychosocial approach is much needed to investigate CLBP, but it also warns against overestimating the direct impact of each potential contributor.

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME.

CME OBJECTIVES

Upon completion of this article, the reader should be able to: (1) Recognize the relation of pain intensity, disability, and loss of function in patients with CLBP; (2) Determine the impact of the most common biological and psychosocial factors in addressing the assessment of chronic back pain patients; and (3) Enhance confidence in selecting the relevant outcomes for the assessment of patients with CLBP following a multidimensional assessment.

LEVEL

Advanced.

ACCREDITATION

The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s)™ . Physicians should only claim credit commensurate with the extent of their participation in the activity.

[Chronic Back Pain]

Chronic back pain is one of the most common diseases in Germany. In many cases, no morphological change is found, so that the genesis remains unspecific in over 90% of patients. This article is intended to provide an overview of drug therapy as well as non-drug measures and summarizes the corresponding guideline recommendations.

Factors Contributing to the Link between Physical Well-Being and Chronic Pain in Young People from Galicia, Northwest Spain

Introduction: The relation between physical well-being and chronic pain is complex and involves several subjective and objective covariates. We aimed to assess the role of mediator, confounder, or interactor played by covariates, including sleep quality, physical activity, perceived stress, smoking, and alcohol drinking in the relation between physical well-being and chronic pain. Method: We used Poisson regression to obtain incidence rate ratios (IRR) of the association between physical well-being and chronic pain in a cohort study carried out among university students. We applied General Structural Equation Modeling (GSEM) to assess mediation and stratum-specific analyses to distinguish confounding from interaction. We computed Relative Excess Risks due to Interaction (RERI), Attributable Proportion (AP), and the Synergy index (S) to measure additive interaction. Results: High physical well-being is related to a large decrease in the risk of chronic pain (IRR^{Total Effect} = 0.58; 95% CI: 0.50-0.81). Perceived stress mediates 12.5% of the total effect of physical well-being on chronic pain. The stratum-specific IRRs of current smokers and non-current smokers were different from each other and were larger than the crude IRR (IRR = 1.49; 95% CI: 1.24-1.80), which indicates that smoking could be both confounder and interactor. Interaction analyses showed that physical activity could act as a potential interactor (RERI = 0.25; 95% CI: 0.13, 0.60). Conclusions: Perceived stress is an important mediator of the relation between physical well-being and chronic pain, while smoking is both a confounder and an interactor. Our findings may prove useful in distinguishing high-risk groups from low-risk groups, in the interventions aimed at reducing chronic pain.

Low back pain among professional bus drivers: a cross-sectional study from Bangladesh

BACKGROUND

Low back pain (LBP) is a common condition contributing to impaired quality of life among professional vehicle drivers. Our study aimed to assess LBP prevalence and associated factors among professional bus drivers in Bangladesh.

METHODS

A cross-sectional study was conducted among 368 professional bus drivers using a semi-structured questionnaire. A Nordic Musculoskeletal Questionnaire (NMQ) subscale was used to measure LBP. Multivariable logistic regression analysis was used to identify the factors associated with LBP.

RESULTS

In the last month, 127 (34.51%) participants reported experiencing pain or discomfort in the lower backside. Multivariable logistic regression analysis showed that age of more than 40 years (adjusted odds ratio (aOR): 2.07, 95% confidence interval (CI): 1.14 to 3.75), the income of more than 15,000 BDT per month (aOR: 1.91, 95% CI: 1.11 to 3.26), work duration more than ten years (aOR: 2.53, 95% CI: 1.12 to 5.70), working more than 15 days per month (aOR: 1.93, 95% CI: 1.02 to 3.65), working more than 10 h per day (aOR: 2.46, 95% CI: 1.05 to 5.75), poor condition of the driving seat (aOR: 1.80, 95% CI: 1.08 to 3.02), current smoking habit (aOR: 9.71, 95% CI: 1.25 to 75.15), illicit substances use (aOR: 1.97, 95% CI: 1.11 to 3.48), and four hours or less sleeping time per day (aOR: 1.83, 95% CI: 1.09 to 3.06) were positively associated with LBP.

CONCLUSION

The high burden of LBP among the participants calls for a focus on this vulnerable group's occupational health and safety, with particular emphasis on implementing standard measures.

Environmental polycyclic aromatic hydrocarbon exposure is associated with low back pain

Several studies have assessed the influence of several often-ignored environmental factors on low back pain (LBP), but the effects of environmental polycyclic aromatic hydrocarbon (PAH) exposure on LBP are unclear. During the 2001-2004 cycle of the National Health and Nutrition Examination Survey (NHANES), our study was given to a representative sample of US participants older than 20 (N = 2743). Environmental PAH exposure was calculated using urinary PAH metabolite concentrations. Weighted logistic regression was performed to assess the connection between PAH levels and LBP, with mediation analysis utilised to explore the underlying mechanism. Levels of 1-hydroxynaphthalene (1-OHNa), 2-hydroxynaphthalene (2-OHNa) and total PAHs had a statistically significant positive association with LBP. The odds ratios per 1-unit increase for log-transformed levels of urinary 1-OHNa, 2-OHNa, and total PAHs with LBP were 1.01 (95% CI 1.02-1.19), 1.19 (95% CI 1.04-1.36) and 1.16 (95% CI 1.03-1.32), respectively. The results revealed a strong dose-response association between 1-OHNa, 2-OHNa, total PAHs, and LBP risk. Subgroup analysis indicated that 2&3-OHPh may increase the risk of LBP in the lower family income subgroup. Gamma-glutamyl transaminase (GGT), known as a biomarker of oxidative stress, was strongly related to PAHs. The relationship between total PAHs and LBP was mediated in part by GGT. Our study demonstrates associations between environmental PAH exposure and LBP that need more research to determine the precise effects of various PAH compounds on LBP.

The role of co-occurring insomnia and mental distress in the association between lumbar disc degeneration and low back pain related disability

BACKGROUND

Lumbar disc degeneration (LDD) is associated with low back pain (LBP). Although both insomnia and mental distress appear to influence the pain experience, their role in the association between LDD and LBP is uncertain. Our objective was to investigate the role of co-occurring insomnia and mental distress in the association between LDD and LBP-related disability.

METHODS

A total of 1080 individuals who had experienced LBP during the previous year underwent 1.5-T lumbar magnetic resonance imaging, responded to questionnaires, and participated in a clinical examination at the age of 47. Full data was available for 843 individuals. The presence of LBP and LBP-related disability (numerical rating scale, range 0-10) were assessed using a questionnaire. LDD was assessed by a Pfirrmann-based sum score (range 0-15, higher values indicating higher LDD). The role of insomnia (according to the five-item Athens Insomnia Scale) and mental distress (according to the Hopkins Symptom Check List-25) in the association between the LDD sum score and LBP-related disability was analyzed using linear regression with adjustments for sex, smoking, body mass index, education, leisure-time physical activity, occupational physical exposure, Modic changes, and disc herniations.

RESULTS

A positive association between LDD and LBP-related disability was observed among those with absence of both mental distress and insomnia (adjusted B = 0.132, 95% CI = 0.028-0.236, p = 0.013), and among those with either isolated mental distress (B = 0.345 CI = 0.039-0.650, p = 0.028) or isolated insomnia (B = 0.207, CI = 0.040-0.373, p = 0.015). However, among individuals with co-occurring insomnia and mental distress, the association was not significant (B = -0.093, CI = -0.346-0.161, p = 0.470).

CONCLUSIONS

LDD does not associate with LBP-related disability when insomnia and mental distress co-occur. This finding may be useful when planning treatment and rehabilitation that aim to reduce disability among individuals with LDD and LBP. Future prospective research is warranted.

Development and Validation of a Risk-Prediction Nomogram for Chronic Low Back Pain Using a National Health Examination Survey: A Cross-Sectional Study

BACKGROUND

Several prognostic factors have been reported for chronic low back pain (CLBP). However, there are no studies on the prediction of CLBP development in the general population using a risk prediction model. This cross-sectional study aimed to develop and validate a risk prediction model for CLBP development in the general population, and to create a nomogram that can help a person at risk of developing CLBP to receive appropriate counseling on risk modification.

METHODS

Data on CLBP development, demographics, socioeconomic history, and comorbid health conditions of the participants were obtained through a nationally representative health examination and survey from 2007 to 2009. Prediction models for CLBP development were derived from a health survey on a random sample of 80% of the data and validated in the remaining 20%. After developing the risk prediction model for CLBP, the model was incorporated into a nomogram.

RESULTS

Data for 17,038 participants were analyzed, including 2693 with CLBP and 14,345 without CLBP. The selected risk factors included age, sex, occupation, education level, mid-intensity physical activity, depressive symptoms, and comorbidities. This model had good predictive performance in the validation dataset (concordance statistic = 0.7569, Hosmer-Lemeshow chi-square statistic = 12.10, p = 0.278). Based on our model, the findings indicated no significant differences between the observed and predicted probabilities.

CONCLUSIONS

The risk prediction model presented by a nomogram, which is a score-based prediction system, can be incorporated into the clinical setting. Thus, our prediction model can help individuals at risk of developing CLBP to receive appropriate counseling on risk modification from primary physicians.

The Effect of Smoking Cessation on Acute Pain: A Systematic Review

Smoking is a known risk factor for developing various pain-related disorders. However, acute pain often triggers the craving for cigarette consumption, resulting in a positive feedback mechanism. In addition, there is evidence of decreased pain tolerance during the early stages of abstinence. Therefore, in this study, we aimed to investigate whether a period of decreased pain tolerance and increased pain intensity occurs during smoking cessation. A systematic literature search was conducted through PubMed and Web of Science databases for controlled studies investigating the influence of smoking cessation on acute (defined as pain presentation of < 3 months) and postoperative pain. The outcomes of interest included pain perception threshold, pain tolerance, pain intensity, and postoperative opioid requirements. The search strategy yielded 1478 studies, of which 13 clinical studies met our inclusion criteria. The included studies collectively represented data from 1721 participants from four countries. Of these, 43.3% of the included individuals were females. The mean age of the included subjects was 44.2 ± 8.2 years. The duration of smoking cessation varied considerably. The shortest duration was 2 h; others investigated the effect after more than 1 month of smoking cessation. Smokers had a history of 14.6 ± 9.9 years of nicotine abuse. The mean number of daily smoked cigarettes was 17.5 ± 10.3. Most studies examined in this systematic review show a negative influence of smoking cessation on acute pain. However, the affected pain modalities, the duration of the altered pain perception, and whether male and female smokers are equally affected could not be ascertained due to high heterogeneity and few available studies.

Duration of Education and Back Pain: Lessons From English Schooling Reforms

This study aimed to examine the associations of increases in the duration of education with back pain using the exogenous variation generated by the English schooling reforms of 1947 and 1972. We analyzed cross-sectional data derived from 9 waves (waves 1-9; 2002-2019) of the English Longitudinal Study of Ageing. An instrumental variables regression using 2-stage least squares with the 2-way cluster-robust standard error was used. The mean severity of back pain, measured using the Numerical Rating Scale, was used as the outcome. A total of 22,868 observations from 5,070 participants were included (the 1947 reform = 16,565 observations from 3,231 participants, mean age = 74.5 years; the 1972 reform = 6,303 observations from 1,839 participants, mean age = 59.3 years). The schooling reforms significantly extended years of school attendance by a mean of 0.57 years for the 1942 reform cohort and 0.66 years for 1972 reform cohort. For participants born within 5 years of the pivotal cohorts, an additional year of education decreased the severity of back pain by 0.78 points (95% confidence interval: 0.65, 0.92) for the 1972 reform cohort. Our finding underscores the importance of the length of education in the reduction of back pain in middle-aged individuals.

A bidirectional study of the association between insomnia, high-sensitivity C-reactive protein, and comorbid low back pain and lower limb pain

OBJECTIVES

To examine the possible bidirectional association between insomnia and comorbid chronic low back pain (LBP) and lower limb pain and to explore whether high-sensitivity C-reactive protein (hsCRP) amplifies these associations.

METHODS

We calculated adjusted risk ratios (RR) with 95% confidence intervals (CI) for the development of insomnia and mild-to-severe chronic LBP and lower limb pain at 11 years follow-up in participants aged ≥32 years and with hsCRP ≤10 mg/L at baseline in 2007-2008: 3,714 without chronic LBP or lower limb pain (sample 1) and 7,892 without insomnia (sample 2).

RESULTS

Compared to participants without chronic pain, participants with comorbid chronic LBP and lower limb pain had a RR of insomnia of 1.37 (95% CI 1.12-1.66). Compared with participants without insomnia, participants with insomnia did not have an increased risk of comorbid chronic LBP and lower limb pain (RR: 1.06, 95% CI 0.76-1.46); however, participants with insomnia had a RR of chronic LBP of 1.20 (95% CI 1.02-1.42). There was no strong amplifying effect of elevated hsCRP (3.00-10.0 mg/L) on these associations.

CONCLUSIONS

These findings suggest that elevated hsCRP does not amplify the associations between insomnia and mild-to-severe chronic LBP and lower limb pain. Further research using data on the temporal relation between insomnia, chronic pain, and inflammatory responses are required to fully understand the causal pathways.

The Effect of High Nicotine Dose on Maximum Anaerobic Performance and Perceived Pain in Healthy Non-Smoking Athletes: Crossover Pilot Study

Background: In recent years, there has been intensive discussion about the positive effect of nicotine usage on enhancing sports performance. It is frequently applied through a non-burned tobacco form before physical activity. Nicotine is under the World Anti-Doping Agency (WADA) 2021 monitoring program. Therefore, study results that reveal either positive or negative effects are expected. This is the pilot study that reports the effect of 8 mg dose of nicotine on performance and perceived pain. Material and Methods: This research aimed to explore the oral intake effect of a high-nicotine dose (8 mg) on the maximum anaerobic performance and other selected physical performance parameters in healthy, well-trained adult athletes (n = 15, age 30.7 ± 3.6, BMI 25.3 ± 1.7). The cross-sectional study protocol included the oral administration of either sublingual nicotine or placebo tablets before the anaerobic load assessed by a standardized 30 s Wingate test of the lower limbs. Afterward, the Borg subjective perception of pain (CR 10) and Borg rating of perceived exertion (RPE) were evaluated. Wilcoxon signed-rank test was used for the analysis of data with a 0.05 level of significance. Results: The results revealed that oral administration of an 8 mg nicotine dose does not significantly improve any of the physical performance parameters monitored. We only reported the statistically significant positive effect in RPE (p = 0.03). Conclusion: Lower perception of pain intensity that we reported after nicotine application might be an important factor that affects performance. However, we did not report any improvement in physical performance parameters.

Association Between Smoking and Pain, Functional Disability, Anxiety and Depression in Patients With Chronic Low Back Pain

Objectives: Chronic low back pain (CLBP) accounts for a majority of the disability associated with LBP, which can produce long-term negative effects. This cross-sectional study aimed to investigate the association between smoking and pain, dysfunction and psychological status in patients with CLBP. Methods: The 54 patients with CLBP were recruited and divided into smoking and non-smoking groups. Their pain, dysfunction, anxiety, depression, fear and quality of life were evaluated. The amount of cigarettes smoked daily was recorded. Results: Significant differences in VAS, ODI, RMDQ and FABQ and the impact of LBP on life and work were found between smoking and non-smoking patients. In addition, a correlation was found between the daily cigarette smoking amount and VAS_max, FABQ_total, SDS and FABQ-W. Moreover, a correlation was observed between the amount of cigarettes smoked daily and the degree of impact of low back pain on work. Conclusion: The study found that smoking affected the aggravation of symptoms in patients with CLBP, which indicated that patients with CLBP and people at risk of LBP should be aware of the harm caused by smoking.

Discogenic Low Back Pain: Anatomy, Pathophysiology and Treatments of Intervertebral Disc Degeneration

Intervertebral disc (IVD) degeneration is a major contributing factor for discogenic low back pain (LBP), causing a significant global disability. The IVD consists of an inner core proteoglycan-rich nucleus pulposus (NP) and outer lamellae collagen-rich annulus fibrosus (AF) and is confined by a cartilage end plate (CEP), providing structural support and shock absorption against mechanical loads. Changes to degenerative cascades in the IVD cause dysfunction and instability in the lumbar spine. Various treatments include pharmacological, rehabilitation or surgical interventions that aim to relieve pain; however, these modalities do not halt the pathologic events of disc degeneration or promote tissue regeneration. Loss of stem and progenitor markers, imbalance of the extracellular matrix (ECM), increase of inflammation, sensory hyperinnervation and vascularization, and associated signaling pathways have been identified as the onset and progression of disc degeneration. To better understand the pain originating from IVD, our review focuses on the anatomy of IVD and the pathophysiology of disc degeneration that contribute to the development of discogenic pain. We highlight the key mechanisms and associated signaling pathways underlying disc degeneration causing discogenic back pain, current clinical treatments, clinical perspective and directions of future therapies. Our review comprehensively provides a better understanding of healthy IVD and degenerative events of the IVD associated with discogenic pain, which helps to model painful disc degeneration as a therapeutic platform and to identify signaling pathways as therapeutic targets for the future treatment of discogenic pain.

Impact of the coronavirus disease 2019 (COVID-19) pandemic on the diagnosis of neck and low back pain in outpatient practices in Germany

Little is known about how COVID-19 has impacted the diagnosis of neck and low back pain in outpatient practices in Germany. Thus, this study aimed to compare the number of new diagnoses of neck and low back pain in German general and orthopedic practices between 2020 and 2021 and 2019. This retrospective study included patients aged ≥ 18 years with at least one visit to one of 915 general and 145 orthopedic practices in Germany in March - December 2019 (N = 2,842,145), March - December 2020 (N = 2,810,179), or March - December 2021 (N = 3,214,419). The number of patients newly diagnosed with neck and low back pain per general and orthopedic practice was compared between March - December 2020 and March - December 2019, and between March - December 2021 and March - December 2019 using Wilcoxon signed-rank tests. Analyses were conducted in general and orthopedic practices separately and were also stratified by sex and age. There was a decrease in new diagnoses of neck and low back pain in general and orthopedic practices between 2020 and 2019, and between 2021 and 2019. This decrease reached statistical significance for neck pain in general practices in 2020 (-12.4 %) and 2021 (-6.1 %), and for low back pain in general practices in 2020 (-9.3 %). Similar findings were obtained in sex- and age-stratified analyses. The COVID-19 pandemic had a negative impact on the diagnosis of neck and low back pain in general and orthopedic practices in Germany. More data from other settings and countries are warranted to confirm or refute these results.

The effect of exercise on health-related quality of life in persons with musculoskeletal pain: A meta-analysis of randomised control trials

OBJECTIVES

Exercise has positive effects on musculoskeletal pain. In this project, the impact of exercise was studied on improving health-related quality of life in persons with musculoskeletal pain.

METHOD

The study design was a systematic review and meta-analysis. A search was conducted to find original studies in four sources, including PubMed, Web of Science, the Cochrane Library and Scopus, and this search was limited to the original articles published until April 2021, which were in English. For each study, the effect size was calculated. The analysis was based on the random-effects method.

RESULT

Twenty-Seven randomised control trial studies were included in the meta-analysis. The total population of participants in the meta-analysis was 1927 persons. Exercise improves health-related quality of life in these persons and the hedges' g was 0.66 (95% CI = 0.38-0.94; I²  = 88.29%).

DISCUSSION

Overall, based on the findings, exercise is associated with improving the health-related quality of life of persons with musculoskeletal pain, and therefore the health implications of this finding are beneficial to the general population and professionals.

A Retrospective Study on Patient-Specific Predictors for Non-Response to Sacroiliac Joint Injections

Intra-articular or peri-articular corticosteroid injections are often used for treatment of sacroiliac joint (SIJ) pain. However, response to these injections is variable and many patients require multiple injections for sustained benefit. In this study, we aim to identify patient-specific predictors of response or non-response to SIJ injections. Identification of these predictors would allow providers to better determine what treatment would be appropriate for a patient with SIJ pain. A retrospective review of 100 consecutive patient charts spanning a 2-year period at an academic multi-specialty pain center was conducted and a multivariate regression analysis was used to identify patient-specific predictors of response to SIJ injections. Our analysis identified that a history of depression and anxiety (OR: 0.233, 95%CI: 0.057-0.954) and increased age (OR: 0.946, 95%CI: 0.910-0.984) significantly reduced the odds of responding to injections. We also found that the associated NPRS score change for SIJ injection responders was less than the minimally clinically significant value of a 2-point differential, suggesting that reported changes in pain scores may not accurately represent a patient's perception of success after SIJ injection. These findings warrant further investigation through a prospective study and can potentially influence clinical decision making and prognosis for patients receiving SIJ injections.

Association of non-chronic low back pain with physical function, endurance, fatigability, and quality of life in middle- and older-aged adults: Findings from Baltimore Longitudinal Study of Aging

Low back pain (LBP) is an important condition associated with high healthcare burden. However, the relationship of this condition with physical function (PF) and health-related quality of life (HRQoL) remains unclear. This is a cross-sectional study that aims to investigate the association between presence and intensity of non-chronic LBP with PF and HRQoL in middle-and older-aged adults. Participants answered questions about presence and intensity of LBP in the previous year, self-reported their PF and HRQoL (SF-12), and underwent objective measures of PF ([ExSPPB] including usual gait speed, narrow walk, chair stands, and standing balance), endurance performance ([EP] long-distance corridor walk) and fatigability. Generalized linear models and logistic regression models were performed. A total of 1500 participants (52.5% women, 70.3% white) aged 69.0 (SD 13.1) years were included. Of those, 642 (42.8%) reported LBP and the mean pain intensity was 4.1 (SD 2.2). After adjustments for potential confounders, presence of LBP was associated with lower self-reported PF (OR 1.73, 95% CI 1.27 to 2.37), lower physical component of HRQoL (β -0.03, 95% CI -0.04 to -0.02) and poorer chair stand performance (β -0.05, 95% CI -0.09 to -0.008). Higher intensity of LBP was associated with lower physical component of HRQoL (β -0.01, 95% CI -0.02 to -0.007), poorer ExSPPB performance (β -0.01, 95% CI -0.02 to -0.004), slower usual gait speed (β -0.01, 95% CI -0.02 to -0.004), lower total standing balance time (β -0.01, 95% CI -0.02 to -0.001) and higher fatigability (OR 1.13, 95% CI 1.01 to 1.25). The presence of non-chronic LBP was more consistently associated with lower self-reported PF, while higher intensity non-chronic LBP was associated with poorer objectively measured PF and fatigability. Collectively, this evidence suggests that although presence of pain may affect perception of function, greater pain intensity appears more strongly associated with unfavorable functional performance in mid-to-late life.

Smoking, alcohol and coffee consumption and risk of low back pain: a Mendelian randomization study

PURPOSE

Low back pain (LBP) is a common health problem in the global population. This study aims to assess whether smoking initiation, alcohol consumption, and coffee consumption are causally with an increased risk of LBP.

METHODS

A two-sample Mendelian Randomization (MR) study was designed, based on summary-level data from the largest published genome-wide association studies. Single nucleotide polymorphisms with genome-wide significance level (P < 5.0 × 10-8) were selected as instrumental variables for each exposure. Standard inverse-variance weighted (IVW) method was used as the primary statistical method. The weighted median, MR-Egger regression, and MR-PRESSO methods, which relax some IV assumptions, were used for sensitivity analysis.

RESULTS

Genetically predicted smoking initiation was causally associated with higher odds of LBP. The pooled OR of LBP using IVW method was 1.36 (95%CI 1.22 1.52; P = 6.0 × 10-8) for one SD increase in the prevalence of smoking initiation, which was supported by the weighted median method (OR: 1.41, 95%CI 1.22, 1.64; P = 5.7 × 10-6). Sensitivity analysis confirmed the robustness of pooled OR of LBP. There was no evidence to suggest a causal effect of alcohol and coffee consumption on LBP. The pooled ORs of LBP were 1.36 (95%CI 0.94, 1.97; P = 0.10) for alcohol consumption and 1.00 (95%CI 0.99, 1.00; P = 0.17) for coffee consumption, respectively.

CONCLUSION

Smoking is casually associated with an increased risk of LBP. Smoking control should be recommended in LBP patients to avoid worsening the disease. The safety of LBP with moderate alcohol and coffee consumption merits more study.

Prevalence and risk factors of chronic low back pain in university athletes: a cross-sectional study

AIM

This study aimed to establish the prevalence of chronic low back pain (CLBP) in university-level athletes and to examine the influence of age, sex, body mass index (BMI), sports discipline, sleep, anxiety, and depression on CLBP. The secondary purpose was to check the association of certain variables in athletes having CLBP with the sports discipline and chronicity of LBP.

METHODS

A total of 340 players (100% response rate) from different sports, aged 18-30 years with at least 1 year of participation in sports at the university level were screened for the present study. The subjects completed a detailed, semi-structured questionnaire that gathered data regarding their demographic variables, personal and pain-related factors. The study was registered on the clinical trials registry, India (CTRI/2021/09/036675).

RESULTS

The results revealed the sport-wise point prevalence as follows: cricket (18.5%), basketball (15.6%), volleyball (20.0%), football (11.4%), badminton (7.7%) and tennis (7.7%). A higher number of years at university-level participation (>4 years), smoking, anxiety and BMI (>25 kg/m²) are risk factors for CLBP. The type of LBP, the intensity of the pain (current and last week), variation of the pain intensity, disability, intake of oral medications, physiotherapy for CLBP, number of missed days of training and number of missed matches are not significantly related to the chronicity of LBP or the sports discipline. Only the number of missed days of training had a significant association with the chronicity of LBP.

CONCLUSIONS

CLBP is a common complaint in Indian university athletes, and our findings indicate the necessity for a specific prevention program.

Prevalence and extent of low back pain and low back-related disability in non-care-seeking working-age adults

OBJECTIVE

To explore the prevalence and extent of low back pain (LBP) and low back-related disability in working-age adults not seeking care.

METHODS

A convenience sample of 101 working-age adults not seeking care for LBP completed the Oswestry Disability Index (ODI) and Roland-Morris Disability Questionnaire (RMDQ) as measures of disability and completed questionnaires that collected information on various demographic and health-related variables. Those reporting current LBP also completed a Numeric Pain Rating Scale (NPRS). Prevalence was assessed based on a dichotomization of whether any disability or pain was reported and also as a continuous variable to assess the extent of pain and disability present for each participant.

RESULTS

Of the 101 participants, 72.3% reported some level of disability (ODI mean = 7.91%, RMDQ mean = 2.63) and 46.5% reported some level of pain (NRPS mean = 3.68). Previous care-seeking for LBP was associated with increased odds of reporting disability (ODI odds ratio [OR] 7.91, 95% confidence interval [CI], 2.43 to 31.18; RMDQ OR 2.69, 95% CI, 1.05 to 7.24), as was reporting any current LBP (ODI OR 9.45, 95% CI, 3.15 to 33.21; RMDQ OR 7.03, 95% CI, 2.82 to 18.89). No other demographic or health-related variables were associated with the presence or extent of pain or disability.

CONCLUSION

Many non-care-seeking individuals reported some level of LBP and/or disability, suggesting that some level of pain and disability may be considered normal, acceptable, or manageable. One-third of individuals with no pain reported some disability.

The Effects of Ambient Temperature on Lumbar Disc Herniation: A Retrospective Study

Purpose

This article was designed to provide critical evidence into the relationship between ambient temperature and intensity of back pain in people with lumbar disc herniation (LDH).

Methods

Data concerning patient's age, gender, diagnostic logout, admission time, discharge time, residence area, and work area (residence area and work area were used to ensure research area) from 2017 to 2019 were obtained from the Neck-Shoulder and Lumbocrural Pain Hospital in Jinan, China. A total of 1,450 hospitalization records were collected in total. The distributed lag non-linear model (DLNM) was used to evaluate the relationship between lag–response and exposure to ambient temperature. Stratification was based on age and gender. Days 1, 5, 20, and 28 prior to admission were denoted as lags 0, 5, 20, and 28, respectively.

Results

An average daily temperature of 15–23°C reduced the risk of hospitalization the most in men. Conversely, temperatures <10°C drastically increased hospitalization in men, particularly in lags 0–5 and lags 20–28. Men aged between 40 and 50 years old showed less effect in pain sensation during ambient temperature.

Conclusion

High or low ambient temperature can increase the hospitalization risk of LDH, and sometimes, the temperature effect is delayed.

Back pain treatment: a new perspective

This article aims to provide new perspectives for the treatment of low back pain (LBP). A narrative literature review highlights the treatment strategies currently anchored in the guidelines as well as the extensive attempts to identify subgroups within the non-specific low back pain (NSLBP) classification. A variety of multimodal approaches exist for both diagnostic assessments and therapy approaches. Nonetheless, there are often gaps in the classification systems as well as in published treatment concepts with regard to the implementation of musculoskeletal functional disorders. Indeed, a growing body of evidence shows that more holistic and flexible approaches are needed to individually diagnose and target the complexity of LBP. As an example, both a diagnostic and a (independently developed) therapeutic LBP concept will be presented and discussed. Ultimately, guidelines and subgroup classification systems can only reflect the complexity of LBP, if they capture its entire multidimensional and biopsychosocial character in both the diagnostic and therapeutic processes. Furthermore, the expansion of the pain definition to include the nociplastic pain mechanism, as an important driver of LBP, has the potential to provide important impulses for further necessary research. In conclusion, the implementation of a functional musculoskeletal approach along with the emerging nociceptive pain concept in individually targeted holistic approaches seems to be the successful way to deal with the complexity of LBP.

Causal effects of psychosocial factors on chronic back pain: a bidirectional Mendelian randomisation study

PURPOSE

Risk factors for chronic back pain (CBP) may share underlying genetic factors, making them difficult to study using conventional methods. We conducted a bi-directional Mendelian randomisation (MR) study to examine the causal effects of risk factors (education, smoking, alcohol consumption, physical activity, sleep and depression) on CBP and the causal effect of CBP on the same risk factors.

METHODS

Genetic instruments for risk factors and CBP were obtained from the largest published genome-wide association studies (GWAS) of risk factor traits conducted in individuals of European ancestry. We used inverse weighted variance meta-analysis (IVW), Causal Analysis Using Summary Effect (CAUSE) and sensitivity analyses to examine evidence for causal associations. We interpreted exposure-outcome associations as being consistent with a causal relationship if results with IVW or CAUSE were statistically significant after accounting for multiple statistical testing (p < 0.003), and the direction and magnitude of effect estimates were concordant between IVW, CAUSE, and sensitivity analyses.

RESULTS

We found evidence for statistically significant causal associations between greater education (OR per 4.2 years of schooling = 0.54), ever smoking (OR = 1.27), greater alcohol consumption (OR = 1.29 per consumption category increase) and major depressive disorder (OR = 1.41) and risk of CBP. Conversely, we found evidence for significant causal associations between CBP and greater alcohol consumption (OR = 1.19) and between CBP and smoking (OR = 1.21). Other relationships did not meet our pre-defined criteria for causal association.

CONCLUSION

Fewer years of schooling, smoking, greater alcohol consumption, and major depressive disorder increase the risk of CBP. CBP increases the risk of greater alcohol consumption and smoking.

The Impact of Smoking on the Development and Severity of Chronic Pain

PURPOSE OF REVIEW

The purpose of this review is to examine the impact of smoking and its role on the development of chronic pain and provide a critical review of recent literature.

RECENT FINDINGS

Recent studies demonstrate the bidirectional and dependent relationship between smoking and chronic pain. Those who are in pain have a more difficult time in the cessation of smoking as well as an increased sensitivity to pain during abstinence, lower confidence, and higher relapse rates. The fear of pain and the anxiety and depression that abstinence causes results in a grim outcome for long-term cessation. The dependent nature between chronic pain and smoking is affected by numerous variables. Providers should consider a multiprong approach to treating chronic pain and targeting smoking cessation treatment by providing motivational therapy, nicotine replacement, and medication therapies to prevent relapse, and providing those who are more likely to relapse with a higher level of care.

Predictors of abdominal pain severity in patients with constipation-prevalent irritable bowel syndrome

BACKGROUND

Symptoms of irritable bowel syndrome (IBS) have been associated to altered colonic motility and sensation. Smoking affects pain perception and is a risk factor in the development of post-infectious IBS, but its effect on abdominal pain and colonic transit remains to be elucidated in IBS.

METHODS

Forty patients with IBS-C and 28 with IBS-M were selected based on Rome IV criteria. Colonic transit time was studied and smoking habit was recorded. Presence of mild or severe abdominal pain and the prevalent pain characteristics (diffuse or localized, chronic or acute, with cramps or gradually distending) were recorded. Data were analyzed by univariate and stepwise multiple logistic regression analysis to verify the risk association between pain and all other variables.

RESULTS

IBS-C patients had a longer transit time in the right colon and scored more chronic pain than IBS-M patients. When severity of abdominal pain was used as discriminating factor, a significant number of subjects reporting severe pain were males and smokers (16/30 vs. 4/38 and 20/30 vs. 4/38, both ƿ<0.001). Multivariate analysis confirmed that smoking was an independent factor associated with severe abdominal pain (OR 14.3, CI 2-99, p=0.007). Smoking was not associated with colonic transit times and colonic transit was not associated with IBS symptoms' severity (both ƿ=N.S.).

CONCLUSIONS

Smoking was the only factor independently associated with severe abdominal pain. As smoking does not seem to affect colonic transit time, we suggest that smoking may influence visceral perception and symptoms severity in IBS patients.

A biopsychosocial examination of chronic back pain, limitations on usual activities, and treatment in Brazil, 2019

Background

Chronic back pain is prevalent in Brazil, leading to enormous healthcare costs and social burdens. It also disproportionately affects low-income and less-healthy people.

Objectives

This study examines the associations of chronic back pain with biological, psychological, and social factors; how it limits usual activities; and how chronic back pain influences the use of treatment services.

Methods

Using Brazil’s National Health Survey (PNS-2019), multivariate logistic regressions were conducted to examine how biological, psychological, and social factors correlate with chronic back pain, limitations on usual activities, and pain treatment.

Results

PNS-2019 data showed that 23.4% (95% CI 22.8–24.0) of Brazilian adults aged over 20 reported back pain. A higher prevalence of chronic back pain was associated with biological factors (older age, being female, overweight or obese, current smoking, and having more chronic conditions), lower social conditions (low education, low per capita household income, non-married, and living in rural areas), and poor psychological health (more depressive symptoms). Chronic back pain is more likely to limit usual activities among those with low social conditions (lower education, lower income), poor physical and behavioral health (obese, current smokers, and those with a greater number of chronic conditions), and worse psychological health (more depressive symptoms). However, married people and those who do not consume alcohol were also more likely to report limited activities. Among those with back pain, 68% received at least one form of treatment. Those with intense limitations on their usual activities were 2.2 times as likely to report treatment. People with higher social conditions (higher income, college education, and private health insurance) were more likely to receive treatment.

Conclusion

The results show significant biological, psychological, and social disparities in the prevalence of chronic back pain in Brazil. The findings point to the need for tailored policies and prevention programs with attention to vulnerable groups. Even though Brazil has universal health care, those with better socioeconomic conditions are more likely to receive treatment.

Perceived pain and smoking interrelations among veterans with chronic pain enrolled in a smoking cessation trial

INTRODUCTION

The Pain and Smoking Inventory (PSI) measures patients' perceived interrelations of their pain and smoking behavior, and comprises three conceptually-distinct domains: smoking to cope with pain (PSI-Cope), pain as a motivator of smoking (PSI-Motivate), and pain as a barrier to cessation (PSI-Barrier). Associations between PSI scores and pain interference and self-efficacy to quit smoking, two measures that can affect cessation outcomes, remain unclear.

METHODS

Secondary analysis of baseline data from 371 Veterans with chronic pain (88% male, M  age = 60) enrolled in a randomized smoking cessation trial. We used sequential multivariate regression models to examine associations between the three PSI domains and pain interference/self-efficacy.

RESULTS

Of 371 Veterans who completed baseline surveys, 88% were male with median age 60 years. PSI-Motivate scores were positively associated with pain interference (B: 0.18, 95% CI: 0.02, 0.34). PSI-Barrier sub-scores were negatively associated with self-efficacy (B: -0.23, 95% CI:-0.36, -0.10).

CONCLUSION

Findings suggest that individuals who hold maladaptive perceptions of pain-smoking interrelations may be more likely to endorse higher pain interference and lower self-efficacy-two established predictors of cessation outcomes. Moreover, each PSI subscale demonstrated unique relationships with the dependent variables, and our results provided support for a three-factor structure. These findings further demonstrate that the PSI comprises three conceptually and empirically distinct domains; future research should evaluate the clinical utility of assessing each domain in relation to cessation outcomes.