New statistical process control charts for overdispersed count data based on the Bell distribution.

Poisson distribution is a popular discrete model used to describe counting information, from which traditional control charts involving count data, such as the c and u charts, have been established in the literature. However, several studies recognize the need for alternative control charts that allow for data overdispersion, which can be encountered in many fields, including ecology, healthcare, industry, and others. The Bell distribution, recently proposed by Castellares et al. (2018), is a particular solution of a multiple Poisson process able to accommodate overdispersed data. It can be used as an alternative to the usual Poisson (which, although not nested in the Bell family, is approached for small values of the Bell distribution) Poisson, negative binomial, and COM-Poisson distributions for modeling count data in several areas. In this paper, we consider the Bell distribution to introduce two new exciting, and useful statistical control charts for counting processes, which are capable of monitoring count data with overdispersion. The performance of the so-called Bell charts, namely Bell-c and Bell-u charts, is evaluated by the average run length in numerical simulation. Some artificial and real data sets are used to illustrate the applicability of the proposed control charts.

Short-term impact of COVID-19 pandemic on low back pain: data from the PAMPA Cohort, Brazil.

BACKGROUND: To evaluate the short-term impact of COVID-19 pandemic on low back pain (LBP) outcomes in southern Brazil. METHODS: Data from the PAMPA Cohort were analyzed. Adults were recruited between June and July 2020 in the Rio Grande do Sul state using online-based strategies. Participants responded a self-reported, online questionnaire on LBP with two timepoints: before (retrospectively) and during COVID-19 pandemic. We assessed LBP experience, LBP-related activity limitation (no/yes), and LBP intensity (0 to 10 [strongest pain]). RESULTS: From a total sample of 2,321 respondents (mean age: 37.6 ± 13.5; 75.4% women), the prevalence of LBP did not change significantly from before (74.7% [95%CI 72.3; 76.9]) to the first months of pandemic (74.2% [95%CI 71.9; 76.3]). However, an increased pain levels (ß: 0.40; 95%CI 0.22; 0.58) and a higher likelihood for activity limitation due to LBP was observed (PR 1.14; 95%CI 1.01; 1.29). Longitudinal analyzes showed that age, gender, BMI, chronic diseases, physical activity, and anxiety and depression symptoms, were associated with LBP in the first pandemic months. CONCLUSION: Although the prevalence of LBP did not change at the first months of COVID-19 pandemic, LBP-induced impairment in daily activities and pain intensity was higher when compared to before the pandemic.

Unraveling water monitoring association towards weather attributes for response proportions data: A unit-Lindley learning.

Learning techniques involve unraveling regression structures, which aim to analyze in a probabilistic frame the associations across variables of interest. Thus, analyzing fraction and/or proportion data may not be adequate with standard regression procedures, since the linear regression models generally assume that the dependent (outcome) variable is normally distributed. In this manner, we propose a statistical model called unit-Lindley regression model, for the purpose of Statistical Process Control (SPC). As a result, a new control chart tool was proposed, which targets the water monitoring dynamic, as well as the monitoring of relative humidity, per minute, of Copiapó city, located in Atacama Desert (one of the driest non-polar places on Earth), north of Chile. Our results show that variables such as wind speed, 24-hour temperature variation, and solar radiation are useful to describe the amount of relative humidity in the air. Additionally, Information Visualization (InfoVis) tools help to understand the time seasonality of the water particle phenomenon of the region in near real-time analysis. The developed methodology also helps to label unusual events, such as Camanchaca, and other water monitoring-related events.

Birthweight, gestational age and familial confounding in sex differences in infant mortality: a matched co-twin control study of Brazilian male-female twin pairs identified by population data linkage.

BACKGROUND: In infancy, males are at higher risk of dying than females. Birthweight and gestational age are potential confounders or mediators but are also familial and correlated, posing epidemiological challenges that can be addressed by studying male-female twin pairs. METHODS: We studied 28 558 male-female twin pairs born in Brazil between 2012 and 2016, by linking their birth and death records. Using a co-twin control study matched for gestational age and familial factors, we applied logistic regression with random effects (to account for paired data) to study the association between male sex and infant death, adjusting for: birthweight, within- and between-pair effects of birthweight, birth order and gestational age, including interactions. The main outcome was infant mortality (0-365 days) stratified by neonatal (early and late) and postneonatal deaths. RESULTS: Males were 100 g heavier and more at risk of infant death than their female co-twins before [odds ratio (OR) = 1.28, 95% confidence interval (CI): 1.11-1.49, P = 0.001] and after (OR = 1.60, 95% CI: 1.39-1.83, P <0.001) adjusting for birthweight and birth order. When adjusting for birthweight within-pair difference and mean separately, the OR attenuated to 1.40 (95% CI: 1.21-1.61, P <0.001), with evidence of familial confounding (likelihood ratio test, P <0.001). We found evidence of interaction (P = 0.001) between male sex and gestational age for early neonatal death. CONCLUSIONS: After matching for gestational age and familial factors by design and controlling for birthweight and birth order, males remain at greater risk of infant death than their female co-twins. Birthweight's role as a confounder can be partially explained by familial factors.

Are leisure-time and work-related activities associated with low back pain during pregnancy?

BACKGROUND: Although working activities are associated with several pregnancy outcomes, there is scarce information regarding the association between working activities and low back pain (LBP) during pregnancy. This study aimed to investigate whether leisure-time and work-related physical activities during pregnancy are associated with LBP. METHODS: Data from the 2015 Pelotas Birth Cohort study were used. Demographic, socioeconomic, gestational, leisure-time (prior to and during pregnancy) and work-related (days of work, hours of work, standing and heavy lifting) physical activity data were collected at birth. LPB was assessed in the 12-month follow-up period. RESULTS: Leisure-time physical activity either prior to and during pregnancy was not associated with LBP. Working during pregnancy, days of work and standing position at work were not associated with self-reported LBP during pregnancy. However, working more than 8 h per day and always lifting heavy objects at work increased the odds ratio for LBP (OR 1.30 95%CI: 1.04; 1.63; and OR: 1.39 95%CI 1.08; 1.81, respectively). In addition, women who had lifted heavy objects often/always, reported an increase in pain intensity. CONCLUSION: Working during pregnancy and days worked per week were not related to experiencing LBP. However, women who worked more than 8 h per day, as well as women who lifted heavy objects at work on a regular basis, were more likely to experience pregnancy-related LBP.

Small Neutral Crowding Solute Effects on Protein Folding Thermodynamic Stability and Kinetics.

Molecular crowding is a ubiquitous phenomenon in biological systems, with significant consequences on protein folding and stability. Small compounds, such as the osmolyte trimethylamine N-oxide (TMAO), can also present similar effects. To analyze the effects arising from these solute-like molecules, we performed a series of crowded coarse-grained folding simulations. Two well-known proteins were chosen, CI2 and SH3, modeled by the alpha-carbon-structure-based model. In the simulations, the crowding molecules were represented by low-sized neutral atom beads in different concentrations. The results show that a low level of the volume fraction occupied by neutral agents can change protein stability and folding kinetics for the two systems. However, the kinetics were shown to be unaffected in their respective folding temperatures. The faster kinetics correlates with changes in the folding route for systems at the same temperature, where non-native contacts were shown to be relevant. The transition states of the two systems with and without crowders are similar. In the case of SH3, there are differences in the structuring of two strands, which may be associated with the increase in its folding rate, in addition to the destabilization of the denatured ensemble. The present study also detected a crossover in the thermodynamic stability behavior, previously observed experimentally and theoretically. As the temperature increases, crowders change from destabilizing to stabilizing agents.

Improved objective Bayesian estimator for a PLP model hierarchically represented subject to competing risks under minimal repair regime.

In this paper, we propose a hierarchical statistical model for a single repairable system subject to several failure modes (competing risks). The paper describes how complex engineered systems may be modelled hierarchically by use of Bayesian methods. It is also assumed that repairs are minimal and each failure mode has a power-law intensity. Our proposed model generalizes another one already presented in the literature and continues the study initiated by us in another published paper. Some properties of the new model are discussed. We conduct statistical inference under an objective Bayesian framework. A simulation study is carried out to investigate the efficiency of the proposed methods. Finally, our methodology is illustrated by two practical situations currently addressed in a project under development arising from a partnership between Petrobras and six research institutes.

Weighted Lindley frailty model: estimation and application to lung cancer data.

In this paper, we propose a novel frailty model for modeling unobserved heterogeneity present in survival data. Our model is derived by using a weighted Lindley distribution as the frailty distribution. The respective frailty distribution has a simple Laplace transform function which is useful to obtain marginal survival and hazard functions. We assume hazard functions of the Weibull and Gompertz distributions as the baseline hazard functions. A classical inference procedure based on the maximum likelihood method is presented. Extensive simulation studies are further performed to verify the behavior of maximum likelihood estimators under different proportions of right-censoring and to assess the performance of the likelihood ratio test to detect unobserved heterogeneity in different sample sizes. Finally, to demonstrate the applicability of the proposed model, we use it to analyze a medical dataset from a population-based study of incident cases of lung cancer diagnosed in the state of São Paulo, Brazil.

Epidural Corticosteroid Injections for Sciatica: An Abridged Cochrane Systematic Review and Meta-Analysis.

STUDY DESIGN: Systematic with meta-analysis OBJECTIVES.: The aim of this study was to investigate the efficacy and safety of epidural corticosteroid injections compared with placebo injection in reducing leg pain and disability in patients with sciatica. SUMMARY OF BACKGROUND DATA: Conservative treatments, including pharmacological and nonpharmacological treatments, are typically the first treatment options for sciatica but the evidence to support their use is limited. The overall quality of evidence found by previous systematic reviews varies between moderate and high, which suggests that future trials may change the conclusions. New placebo-controlled randomized trials have been published recently which highlights the importance of an updated systematic review. METHODS: The searches were performed without language restrictions in the following databases from 2012 to 25 September 2019: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, PubMed, Embase, CINAHL, PsycINFO, International Pharmaceutical Abstracts, and trial registers. We included placebo-controlled randomized trials investigating epidural corticosteroid injections in patients with sciatica. The primary outcomes were leg pain intensity and disability. The secondary outcomes were adverse events, overall pain, and back pain intensity. We grouped similar trials according to outcome measures and their respective follow-up time points. Short-term follow-up (>2 weeks but ≤3 months) was considered the primary follow-up time point due to the expected mechanism of action of epidural corticosteroid injection. Weighted mean differences (MDs) and risk ratios (RRs) with their respective 95% confidence intervals (CIs) were estimated. We assessed the overall quality of evidence using the GRADE approach and conducted the analyses using random effects. RESULTS: We included 25 clinical trials (from 29 publications) providing data for a total of 2470 participants with sciatica, an increase of six trials when compared to the previous review. Epidural corticosteroid injections were probably more effective than placebo in reducing short-term leg pain (MD -4.93, 95% CI -8.77 to -1.09 on a 0-100 scale), short-term disability (MD -4.18, 95% CI: -6.04 to -2.17 on a 0-100 scale) and may be slightly more effective in reducing short-term overall pain (MD -9.35, 95% CI -14.05 to -4.65 on a 0-100 scale). There were mostly minor adverse events (i.e., without hospitalization) after epidural corticosteroid injections and placebo injections without difference between groups (RR 1.14, 95% CI: 0.91-1.42). The quality of evidence was at best moderate mostly due to problems with trial design and inconsistency. CONCLUSION: A review of 25 placebo-controlled trials provides moderate-quality evidence that epidural corticosteroid injections are effective, although the effects are small and short-term. There is uncertainty on safety due to very low-quality evidence. LEVEL OF EVIDENCE: 1.

Pelvic floor muscle training for women with lumbopelvic pain: A systematic review and meta-analysis.

BACKGROUND AND OBJECTIVE: It has been suggested that pelvic floor dysfunction may contribute to the development of lumbopelvic pain as a result of changes in trunk muscle control. However, there is limited evidence that pelvic floor muscle training (PFMT) can improve clinical outcomes in women with lumbopelvic pain. DATABASES AND DATA TREATMENT: Six databases were searched for randomized controlled trials (RCTs) comparing the effectiveness of PFMT to other conservative interventions (usual physiotherapy care or minimal intervention), no treatment or placebo interventions on pain and disability in women with lumbopelvic pain. RESULTS: We included eight RCTs totalling 469 participants. PFMT was more effective than minimal intervention for lumbopelvic pain [mean difference (MD) 15.9/100 (95% confidential interval (CI), 8.2 to 23.6; p = 0.00; I2  = 3.92%)] and disability [standardized mean difference (SMD) 0.5 (95% CI 0.1-0.9; p = 0.00; I2  = 0%)] during pregnancy. PFMT was more effective than usual physiotherapy care for pain (MD 11.7/100 [95% CI 7.5-15.9; p = 0.00; I2  = 94.14%]) and disability (SMD 0.3 (95% CI 0.0-0.6; p = 0.01; I2  = 82.54%]) in non-pregnant women. Effect sizes were in general of arguable clinical relevance. CONCLUSIONS: Overall, the certainty of the evidence was very low to low. There is no conclusive evidence that the addition of PFMT to usual physiotherapy care or minimal intervention is superior to minimal intervention and usual care alone given the small number of studies and high levels of heterogeneity of included studies. Further well-designed trials are needed to establish the effectiveness of PFMT for lumbopelvic pain in women.

Physical Activity Before or During Pregnancy and Low Back Pain: Data From the 2015 Pelotas (Brazil) Birth Cohort Study.

BACKGROUND: To investigate whether engagement in leisure-time physical activity before or during pregnancy is associated with low back pain (LBP) outcomes during pregnancy and postpartum prevalence of LBP in women who reported LBP during pregnancy. METHODS: Data from the 2015 Pelotas Birth Cohort Study, were used. Demographic, socioeconomic, and gestational characteristics, as well as physical activity prior to and during pregnancy were recorded at perinatal assessment. LBP outcomes during pregnancy (pain intensity, activity limitation, and care seeking) and postpartum (prevalence of LBP) were collected at the 1-year follow-up. RESULTS: Pain intensity, care seeking, and prevalence of LBP postpartum period were not associated with physical activity either before or during pregnancy. However, women engaged in physical activity during pregnancy and at least for 2 trimesters had lower odds ratio of activity limitation associated with LBP during pregnancy (odds ratio: 0.60; 95% confidence interval, 0.41 to 0.88; odds ratio: 0.20; 95% confidence interval, 0.04 to 0.86, respectively). CONCLUSION: Meeting the recommended levels of physical activity during pregnancy is associated with less activity limitation related to LBP during pregnancy. However, physical activity levels, either before or during pregnancy, were not associated with pain intensity, care seeking, and postpartum LBP.

Modeling traumatic brain injury lifetime data: Improved estimators for the Generalized Gamma distribution under small samples.

In this paper, from the practical point of view, we focus on modeling traumatic brain injury data considering different stages of hospitalization, related to patients' survival rates following traumatic brain injury caused by traffic accidents. From the statistical point of view, the primary objective is related to overcoming the limited number of traumatic brain injury patients available for studying by considering different estimation methods to obtain improved estimators of the model parameters, which can be recommended to be used in the presence of small samples. To have a general methodology, at least in principle, we consider the very flexible Generalized Gamma distribution. We compare various estimation methods using extensive numerical simulations. The results reveal that the penalized maximum likelihood estimators have the smallest mean square errors and biases, proving to be the most efficient method among the investigated ones, mainly to be used in the presence of small samples. The Simulated Annealing technique is used to avoid numerical problems during the optimization process, as well as the need for good initial values. Overall, we considered an amount of three real data sets related to traumatic brain injury caused by traffic accidents to demonstrate that the Generalized Gamma distribution is a simple alternative to be used in this type of applications for different occurrence rates and risks, and in the presence of small samples.

Is occupational or leisure physical activity associated with low back pain? Insights from a cross-sectional study of 1059 participants.

BACKGROUND: Low back pain is a highly prevalent and disabling musculoskeletal disorder. Physical activity is widely used as a prevention strategy for numerous musculoskeletal disorders; however, there is still conflicting evidence as to whether physical activity is a protective or risk factor for low back pain or whether activity levels differ between people with and without low back pain. OBJECTIVE: To investigate the association between low back pain and different types (occupational and leisure) and intensities (moderate and vigorous) of physical activity. METHODS: This is cross-sectional observational study. We included in this study a total of 1059 individuals recruited from a Spanish twin registry with data available on low back pain. OUTCOME: Self-reported leisure and occupational physical activity were the explanatory variables. The low back pain outcome used in this study was recurrent low back pain. RESULTS: Our results indicate that leisure physical activity is associated with a lower prevalence of recurrent low back pain. In contrast, occupational physical activity, such as carrying, lifting heavy weight while inclined, awkward postures (e.g. bending, twisting, squatting, and kneeling) are associated with a higher prevalence of recurrent low back pain. There was no statistically significant association between other occupational physical activities, such as sitting or standing, and low back pain. CONCLUSION: Leisure and occupational physical activity are likely to have an opposed impact on low back pain. While leisure physical activity appears to be protective, occupational physical activity appears to be harmful to low back pain. Future longitudinal studies should assist in formulating guidelines addressing specific types and intensity of physical activity aimed at effectively preventing low back pain.

Physical activity as a prognostic factor of pain intensity and disability in patients with low back pain: A systematic review.

BACKGROUND AND OBJECTIVE: Identifying factors that influence the course of low back pain (LBP) is important to help clinicians to identify those patients at higher risk of non-recovery. The objective of this systematic review was to investigate the prognostic role of physical activity in the course of LBP. DATABASES AND DATA TREATMENT: Literature searches were conducted in five electronic databases from their inception to February 2018. Prospective cohort studies investigating the influence of any type of physical activity in people with LBP were considered eligible. The primary outcomes were pain intensity and disability. Two independent reviewers extracted the data and assessed the methodological quality of the included studies. Results were stratified according to participants' symptoms duration at baseline. RESULTS: Twelve studies were considered eligible for this review. Of these, six included patients with chronic LBP, four studies did not specify the patients' duration of symptoms, one study included patients with acute LBP, and one study included patients with subacute LBP. Included studies were heterogeneous in terms of physical activity assessment, outcomes, follow-up duration, and statistical methods, therefore, pooling of results was not performed. We found limited evidence to support the prognostic role of physical activity in the course of LBP. CONCLUSIONS: Our review identified limited evidence supporting physical activity as a prognostic factor in LBP. Future cohort studies are needed to clarify the strength and importance of this association. SIGNIFICANCE: Despite recent research in the area, this systematic review shows that there is low quality evidence that physical activity may not be a prognostic factor for predicting pain and disability in patients with LBP.

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.

Are perinatal factors associated with musculoskeletal pain across the lifespan? A systematic review with meta-analysis.

BACKGROUND: Musculoskeletal conditions are common health issues with great impact on individuals. Although many factors have been associated with the development of musculoskeletal pain, such as perinatal factors, its aetiology is still poorly understood. OBJECTIVE: To systematically investigate whether perinatal factors can increase the risk of having musculoskeletal pain across the lifespan. METHODS: MEDLINE, CINAHL, Scopus, Web of Science and EMBASE databases were searched from their inception to December 2017. Descriptors used in our search strategy were related to "perinatal factors" and "musculoskeletal pain". There were no language, age, sex or date restrictions. Meta-analysis was used to pool the estimates of association between perinatal factors and musculoskeletal pain. RESULTS: Among the six articles included in this systematic review, three were extracted for the meta-analysis. The pooled of three and two studies showed no association between chronic musculoskeletal pain and low birth weight (OR 1.8, 95% CI 0.9-3.8, I2 = 0; n = 157) or pre-term birth (OR 0.5, 95% CI 0.0-4.5; I2 = 78%; n = 374) in adults, respectively. Overall, the quality of evidence after applying the GRADE approach was very low across all the studies. CONCLUSION: In adults, our meta-analysis showed no association between birth weight or pre-term birth and musculoskeletal pain, and the quality of the evidence was very low. Thus, the very low quality of evidence and limited number of studies do not suggest a direct clear association. Further high-quality longitudinal studies accounting for more relevant confounders are needed to better understand the complex mechanism that may operate between perinatal factors and musculoskeletal pain.

Physical activity and disability measures in chronic non-specific low back pain: a study of responsiveness.

OBJECTIVES:: To compare the responsiveness of disability measures with physical activity measures in patients with chronic low back pain (CLBP) undergoing a course of physical therapy treatment. DESIGN:: This is a prospective cohort study with two-month follow-up. SUBJECTS:: A total of 106 patients presenting with non-specific CLBP of more than three months duration were recruited. MAIN MEASURES:: Disability measures investigated were Quebec Back Pain Disability Scale and Roland Morris Disability Questionnaire. Physical activity measures analyzed include the Baecke Habitual Physical Activity Questionnaire and objective measures derived from an accelerometer (i.e. total time spent in moderate-to-vigorous and light physical activity, number of steps and counts per minute). Disability and physical activity measures were collected at the baseline and after eight weeks of treatment. For the responsiveness analyses, effect size (ES) and standardized response mean (SRM) were calculated. Correlations between the change in disability and physical activity measures were calculated. RESULTS:: Responsiveness for disability measures was considered to be large with ESs ranging from -1.03 to -1.45 and SRMs ranging from -0.99 to -1.34, whereas all physical activity measures showed values lower than 0.20. Changes in disability measures did not correlate with changes in physical activity measures (correlation coefficients ranged from -0.10 to 0.09). CONCLUSION:: Disability measures were responsive after a course of physical therapy treatment in patients with CLBP. The lack of responsiveness in the physical activity measures might be due to the inability of these measures to detect change over time or the use of an intervention not designed to increase physical activity levels.

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.

Physical Activity-Based Interventions Using Electronic Feedback May Be Ineffective in Reducing Pain and Disability in Patients With Chronic Musculoskeletal Pain: A Systematic Review With Meta-Analysis.

OBJECTIVE: To investigate the effectiveness of physical activity-based interventions using electronic feedback in reducing pain and disability compared to minimal or no interventions in patients with chronic musculoskeletal pain. DATA SOURCES: The following electronic databases were searched: EMBASE, MEDLINE, Cochrane Central Register of Controlled Trials, PsycINFO, Cumulative Index to Nursing and Allied Health Literature, SPORTDiscus, Web of Science, Physiotherapy Evidence Database, and main clinical trial registers. STUDY SELECTION: Randomized controlled trials investigating the effect of physical activity interventions using electronic feedback (eg, physical activity monitors) on pain and disability compared to minimal or no interventions in adults with chronic musculoskeletal pain were considered eligible. DATA EXTRACTION: Pooled effects were calculated using the standardized mean difference (SMD), and the Grading of Recommendations Assessment, Development and Evaluation system was used to assess the overall quality of the evidence. DATA SYNTHESIS: Four published randomized controlled trials and 4 registered unpublished randomized controlled trials were included. At short-term follow-up, pooled estimations showed no significant differences in pain (2 trials: n=116; SMD=-.50; 95% confidence interval, -1.91 to 0.91) and disability (2 trials: n=116; SMD=-.81; 95% confidence interval, -2.34 to 0.73) between physical activity-based interventions and minimal interventions. Similarly, nonsignificant results were found at intermediate-term follow-up. According to Grading of Recommendations Assessment, Development and Evaluation, the overall quality of the evidence was considered to be of low quality. CONCLUSIONS: Our findings suggest that physical activity-based interventions using electronic feedback may be ineffective in reducing pain and disability compared to minimal interventions in patients with chronic musculoskeletal pain. Clinicians should be cautious when implementing this intervention in patients with chronic musculoskeletal pain.

Correlates of a Recent History of Disabling Low Back Pain in Community-dwelling Older Persons: The Pain in the Elderly (PAINEL) Study.

OBJECTIVES: To investigate the correlates of a recent history of disabling low back pain (LBP) in older persons. MATERIALS AND METHODS: The Pain in the Elderly (PAINEL) Study was derived from the Frailty among Brazilian Older Adults (FIBRA) Network Study. Data were collected through face-to-face/telephone interviews and clinical examination. A series of logistic regressions assessed associations between a recent history of disabling LBP and sociodemographic, physical/lifestyle, and psychological factors. RESULTS: Of the 378 community-dwelling elders included in the study (age±SD, 75.5±6.1), 9.3% experienced LBP that was bad enough to limit or change their daily activities during the past year. Those reporting a recent history of disabling LBP were more likely to be women and under financial strain, to present poor self-rated health, overweight, multimorbidity, low physical activity level, fatigue, depressive symptomatology/diagnosis and fear beliefs, and to report decreased sleep time, prolonged sitting time, chronic pain (in location other than lower back), and frequently recurring LBP. The multivariate logistic regression analysis indicated that overweight (odds ratio [OR], 29.6; 95% confidence interval [CI], 2.3-391.0), low physical activity level (OR, 4.4; 95% CI, 1.3-15.4), fatigue (OR, 10.3; 95% CI, 2.4-43.4), depression diagnosis (OR, 4.9; 95% CI, 1.3-18.4), and frequently recurring LBP (OR, 4.6; 95% CI, 1.0-20.1) were independently associated with a recent history of disabling LBP. DISCUSSION: Our study supports the link between disabling LBP and other age-related chronic conditions in a middle-income country with a rapidly aging population.