Understanding chronic pain in older adults: Abdominal fat is where it is at

Obesity, Adipokines, and Chronic and Persistent Pain in Rheumatoid Arthritis

We aimed to determine whether adipokines are associated with pain and polysymptomatic distress in patients with rheumatoid arthritis (RA) over time in a large patient registry. The cohort study was conducted in a subset of Forward; a patient-based multi-disease, multipurpose rheumatic disease registry with patients enrolled from community-based rheumatology practices across the U.S. Adipokines (adiponectin, leptin, and fibroblast growth factor[FGF]-21) were measured on stored serum as part of a multi-analyte panel. Body mass index (BMI), pain, polysymptomatic distress, and other patient-reported outcomes (PROs) were reported on biannual questionnaires. Linear regression was used to evaluate independent associations between BMI, adipokines, and PROs. Cox proportional hazards models evaluated independent associations between adipokines and clinically meaningful changes in pain over time (change in numerical rating>1.1 [range 0-10], sustained over 1 year). Among 645 patients included in these analyses, there were significant differences in RA characteristics, comorbidity, PROs, and adipokines across obesity categories. Of note, severely obese patients were more likely to experience greater pain, polysymptomatic distress, and fatigue. Patients with higher FGF-21 levels had higher pain and polysymptomatic stress at baseline, were more likely to use opioids, and were more likely to have sustained worsening pain over time [HR (per 1 SD) (95% CI): 1.22 (1.02,1.46) P = .03] independent of BMI. Obesity and elevated levels of FGF-21 are associated with pain and polysymptomatic distress in RA. Elevated FGF-21 levels may help identify those at risk of worsening pain trajectories over time, independent of BMI. PERSPECTIVE: This study characterizes the relationship between severe obesity and pain and polysymptomatic distress in patients with rheumatoid arthritis and demonstrates that the adipocytokine fibroblast growth factor-21 is independently associated with pain and predicts a worsening trajectory over time. Further mechanistic studies are needed.

Obesity and Response to Advanced Therapies in Rheumatoid Arthritis

OBJECTIVE

We performed a study of tumor necrosis factor inhibitors (TNFi) compared to non-TNFi biologic therapies in rheumatoid arthritis to test whether body mass index (BMI) modified the effect of each therapy.

METHODS

We utilized data from CorEvitas. We studied 3 clinical outcomes based on the Clinical Disease Activity Index (CDAI) at 6 months from therapy initiation: 1) achievement of low disease activity (LDA); 2) a change as large as the minimum clinically important difference (MCID); and 3) the absolute change. We categorized BMI and utilized restricted cubic splines to consider nonlinear associations. We used linear and logistic regression to evaluate associations with response, adjusting for confounders. To determine if comparative effectiveness of therapy varied by BMI, we tested for interactions between BMI and class of therapy.

RESULTS

The sample included 2,891 TNFi and 3,010 non-TNFi initiators. Among all initiators, those with severe obesity experienced lower odds of achieving LDA or MCID and less improvement in CDAI score, although associations were attenuated with adjustment. Low BMI was associated with reduced response rates in adjusted models including lower odds of LDA (odds ratio 0.32 [95% confidence interval (95% CI) 0.15, 0.71], P = 0.005). Analyses stratified by TNFi and non-TNFi therapies demonstrated no differences in clinical response rates for TNFi versus non-TNFi across BMI categories (all P for interaction >0.05). Estimates for non-TNFi biologics fit within the 95% CI for TNFi.

CONCLUSION

This study observed lower response rates among obese and underweight patients and no evidence of a superior effect of non-TNFi therapy over TNFi therapy in particular BMI categories.

Patient reported outcomes measures (PROMs) trajectories after elective hip arthroplasty: a latent class and growth mixture analysis

Background

Patient-reported outcome measures (PROMs) are an extensively used tool to assess and improve the quality of healthcare services. PROMs can be related to individual demographic and clinical characteristics in patients undergoing hip arthroplasty (HA). The aim of this study is to identify distinct subgroups of patients with unique trajectories of PROMS scores and to determine patients’ features associated with these subgroups.

Methods

We conducted a prospective, cohort study in which PROMs questionnaires (Euro Quality 5 Dimensions 3L, EQ-5D-3L, Euro-Quality-Visual-Analytic-Score, EQ-VAS, Hip disability and Osteoarthritis Outcome Score, HOOS-PS) were administered to patients undergoing elective HA pre-operatively, and at 6 and 12 months after surgery. For each measure, latent class growth analysis and growth mixture models were used to identify subgroups of patients with distinct trajectories of scores. Demografic and clinical predictors of the latent classes in growth mixture model were identified using a 3-step approach.

Results

We found three distinct trajectories for each PROM score. These trajectories indicated a response heterogeneity to the HA among the patients (n = 991). Patient’s gender, ASA score, and obesity were significantly associated with different PROMs trajectories.

Conclusions

We identified three distinct trajectories for each of the three PROMs indicators. Several demographic and clinical characteristics are associated with the different trajectories of PROMs at 6 and 12 months after HA and could be used to identify groups of patients with different outcomes following HA surgery. These findings underline the importance of patient-centered care, supporting the usefulness of integrating PROMs data alongside routinely collected healthcare records for guiding clinical care and maximizing patients’ positive outcomes.

Trial registration: Protocol version (1.0) and trial registration data are available on the platform www.clinicaltrial.gov with the identifier NCT03790267, posted on December 31, 2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41687-022-00503-5.

Central Obesity Is Associated With an Increased Rate of Multisite Pain in Older Adults

Objective

Central obesity has been associated with several adverse health events, but little research exists about the longitudinal effects of central obesity on multisite pain. The purpose of this study was to assess if central obesity, as measured by waist circumference measurement, was associated with an increased rate of having multisite pain among older adults aged 65 years and older.

Design

The National Health and Aging Trends Study is a longitudinal cohort study initiated in 2011 and intended to be representative of Medicare beneficiaries in the contiguous United States.

Methods

There were 7,145 community-dwelling participants included in this study. Data for this study were collected annually between 2011 and 2018. Researchers assessed if waist circumference risk level was associated with an increased rate ratio of multisite pain. Weighted data were used in a multivariable generalized estimating equation model that used a log link specified with a Poisson distribution.

Results

Participants with high-risk waist circumferences (98 cm or greater for women and 109 cm or greater for men) had a 11% higher rate of multisite pain than those with low-risk waist circumferences [rate ratio (RR) 1.11, 95% CI: 1.07–1.15] adjusting for gender, age, race, education, probable major depression, arthritis, and multimorbidity count.

Conclusion

As measured by waist circumference, central adiposity is associated with multisite pain in older adults. While more research is needed, reducing waist circumference may prove beneficial in reducing the burden of multisite pain.

Fibromyalgia Syndrome and Cognitive Decline: The Role of Body Mass Index and Clinical Symptoms

The high prevalence of obesity and overweight in fibromyalgia (FM) may be an important factor in the well-known cognitive deficits seen in the disorder. This study analyzed the influence of body mass index (BMI) and primary clinical symptoms of FM (pain, fatigue, insomnia, anxiety, and depression) on attention, memory, and processing speed in FM. Fifty-two FM patients and thirty-two healthy participants completed cognitive tasks assessing selective, sustained, and divided attention; visuospatial and verbal memory; and information processing speed. Furthermore, they were evaluated in terms of the main clinical symptoms of the disorder. FM patients showed a marked reduction of cognitive performance in terms of selective, sustained, and divided attention; visuospatial memory; and processing speed, but no group differences were observed in verbal memory. BMI negatively affects sustained and selective attention, verbal memory, and processing speed and is the main predictor of performance in these basic cognitive domains. Our findings confirm the presence of cognitive deficits with respect to attention and visual memory, as well as slower processing speed, in FM. Moreover, the results support a role of BMI in the observed cognitive deficits. Interventions increasing physical activity and promoting cognitive stimulation could be useful for strengthening cognitive function in FM patients.

Fibromyalgia and obesity: A comprehensive systematic review and meta-analysis

INTRODUCTION

Obesity has been associated with several complications, including musculoskeletal disorders. Aim of the present systematic review was to identify all available evidence on the relationship between fibromyalgia (FM) and obesity, including epidemiological association, impact of obesity on FM severity and effect of weight loss strategies on FM symptoms.

METHODS

MedLine, Cochrane Central Register of Controlled Trials and Web of Science databases were searched up to September 2020 to identify eligible articles. Data from studies reporting the prevalence of obesity in FM patients were pooled using a random-effects model.

RESULTS

After removal of duplicate records, 393 studies proceeded to review. A total of 41 articles were deemed eligible for inclusion in final synthesis. Quality assessment revealed that the overall risk of bias was high. The overall prevalence of obesity in FM was 35.7% (95% CI: 31.8 - 39.9%), with higher figures reported for USA. The majority of studies included demonstrated that obesity is associated with different domains of the disorder, including composite measures of activity, pain severity, tender point count, stiffness, fatigue, physical functioning/disability, sleep, cognitive dysfunction, and quality of life; the strength of correlation was weak on average. Inconsistent data were available regarding the correlation with depression and anxiety. Only few studies addressed the effect of therapeutic weight loss in FM, either by bariatric surgery, diet/exercise combination or behavioral weight loss, providing preliminary evidence for a potential benefit of weight loss in ameliorating FM symptoms.

CONCLUSIONS

Available data support a potential interplay between obesity and FM-related symptoms. Weight management should be encouraged in patients with FM.

Modulation of Pain Sensitivity by Chronic Consumption of Highly Palatable Food Followed by Abstinence: Emerging Role of Fatty Acid Amide Hydrolase

There is a strong relationship between palatable diet and pain sensitivity, and the cannabinoid and opioid systems might play an important role in this correlation. The palatable diet used in many animal models of obesity is the cafeteria (CAF) diet, based on human food with high sugar, salt, and fat content. In this study, we investigated whether long-term exposure to a CAF diet could modify pain sensitivity and explored the role of the cannabinergic system in this modification. Male Sprague–Dawley rats were divided into two groups: one fed with standard chow only (CO) and the other with extended access (EA) to a CAF diet. Hot plate and tail flick tests were used to evaluate pain sensitivity. At the end of a 40-day CAF exposure, EA rats showed a significant increase in the pain threshold compared to CO rats, finding probably due to up-regulation of CB1 and mu-opioid receptors. Instead, during abstinence from palatable foods, EA animals showed a significant increase in pain sensibility, which was ameliorated by repeated treatment with a fatty acid amide hydrolase inhibitor, PF-3845 (10 mg/kg, intraperitoneally), every other day for 28 days. Ex vivo analysis of the brains of these rats clearly showed that this effect was mediated by mu-opioid receptors, which were up-regulated following repeated treatment of PF-3845. Our data add to the knowledge about changes in pain perception in obese subjects, revealing a key role of CB1 and mu-opioid receptors and their possible pharmacological crosstalk and reinforcing the need to consider this modulation in planning effective pain management for obese patients.

Evaluation of temporomandibular disorders and oral health-related quality of life with obese patients

Objective: The aim of this study was to investigate the relationship between temporomandibular disorders and oral health impact profile in healthy, overweight, and obese patients.Methods: This study was carried out on 1528 individuals divided into three groups as healthy, overweight, and obese patients. Diagnostic Criteria for Temporomandibular Disorders, Fonseca's questionnaire, and Oral Health Impact Profile-14 (OHIP-14) forms were used.Results: Gender, classification, pain, temporomandibular joint noise, and open-lock of the jaw of healthy, overweight, and obese groups were found to be related. The differences in the Fonseca and the OHIP-14 total scores according to the groups were found to be statistically significant. The correlation between the Fonseca total score and age was positive and significant.Conclusion: In the obese patients, both total Fonseca and OHIP-14 values were found to be higher. Also, the presence of pain in the obese patients was found to be higher.

Physical activity containing behavioural interventions for adults living with modifiable chronic non-communicable diseases in Africa: a systematic mixed-studies review

Background

Physical activity improves physiological, cognitive and psychosocial functioning in chronic non-communicable diseases (NCDs). This study reviewed papers on the effects and patients' experiences of physical activity interventions for chronic NCDs in Africa.

Methods

We conducted a systematic review of clinical and qualitative studies by searching eight bibliographic databases and grey literature until 19 April 2017. The mixed-methods appraisal and Cochrane Collaboration's tools were used for quality and risk of bias assessments. Three-stage sequential explanatory syntheses were done.

Results

One randomized controlled trial (RCT), two non-controlled before and after studies and two qualitative studies of diabetic South African and Reunion patients were included. Exercise and sports unrelated to home and occupational activities were increased in the long term (1 year, moderate quality evidence) and short term immediately after a 4-week intervention (low quality evidence). There was conflicting evidence of intervention effects on home and occupational physical activities. Behaviour-change techniques improving chronic disease knowledge, addressing environmental barriers and stimulating/supporting physical activity were important to patients. Procedure-related components-health professional training and adequate health facilities-were important to patients, but were not addressed.

Conclusion

High quality RCTs are needed to confirm the intervention components for improving physical activity for chronic NCD management in Africa.

Weight loss interventions for adults with overweight/obesity and chronic musculoskeletal pain: a mixed methods systematic review

Worldwide prevalence of adult overweight and obesity is a growing public health issue. Adults with overweight/obesity often have chronic musculoskeletal pain. Using a mixed-methods review, we aimed to quantify the effectiveness and explore the appropriateness of weight loss interventions for this population. Electronic databases were searched for studies published between 01/01/90 and 01/07/16. The review included 14 randomized controlled trials that reported weight and pain outcomes and three qualitative studies that explored perceptions of adults with co-existing overweight/obesity and chronic musculoskeletal pain. The random-effects pooled mean weight loss was 4.9 kg (95%CI:2.9,6.8) greater for intervention vs control. The pooled mean reduction in pain was 7.3/100 units (95%CI:4.1,10.5) greater for intervention vs control. Study heterogeneity was substantial for weight loss (I²  = 95%, tau = ±3.5 kg) and pain change (I²  = 67%, tau = ±4.1%). Meta-regression slopes for the predictors of study quality, mean age and baseline mean weight on mean study weight reduction were shallow and not statistically significant (P > 0.05). The meta-regression slope between mean pain reduction and mean weight lost was shallow, and not statistically significant, -0.09 kg per unit pain score change (95%CI:-0.21,0.40, P = 0.54). Meta-synthesis of qualitative findings resulted in two synthesized findings; the importance of healthcare professionals understanding the effects of pain on ability to control weight and developing management/education programmes that address comorbidity.

What are the similarities and differences between healthy people with and without pain?

BACKGROUND AND AIMS

Knowledge of pain characteristics among the healthy population or among people with minimal pain-related disability could hold important insights to inform clinical practice and research. This study investigated pain prevalence among healthy individuals and compared psychosocial and physical characteristics between adults with and without pain.

METHODS

Data were from 1,000 self-reported healthy participants aged 3-101 years (1,000 Norms Project). Single-item questions assessed recent bodily pain ("none" to "very severe") and chronic pain (pain every day for 3 months in the previous 6 months). Assessment of Quality of Life (AQoL) instrument, New Generalised Self-Efficacy Scale, International Physical Activity Questionnaire, 6-min walk test, 30-s chair stand and timed up-and-down stairs tests were compared between adults with and without pain.

RESULTS

Seventy-two percent of adults and 49% of children had experienced recent pain, although most rated their pain as mild (80% and 87%, respectively). Adults with recent pain were more likely to be overweight/obese and report sleep difficulties, and had lower self-efficacy, AQoL mental super dimension scores and sit-to-stand performance, compared to adults with no pain (p<0.05). Effect sizes were modest (Cohen's d=0.16-0.39), therefore unlikely clinically significant. Chronic pain was reported by 15% of adults and 3% of children. Adults with chronic pain were older, more likely to be overweight/obese, and had lower AQoL mental super dimension scores, 6-min walk, sit-to-stand and stair-climbing performance (p<0.05). Again, effect sizes were modest (Cohen's d=0.25-0.40).

CONCLUSIONS

Mild pain is common among healthy individuals. Adults who consider themselves healthy but experience pain (recent/chronic) display slightly lower mental health and physical performance, although these differences are unlikely clinically significant.

IMPLICATIONS

These findings emphasise the importance of assessing pain-related disability in addition to prevalence when considering the disease burden of pain. Early assessment of broader health and lifestyle risk factors in clinical practice is emphasised. Avenues for future research include examination of whether lower mental health and physical performance represent risk factors for future pain and whether physical activity levels, sleep and self-efficacy are protective against chronic pain-related disability.

Body-scaled action in obesity during locomotion: Insights on the nature and extent of body representation disturbances

OBJECTIVE

Conscious perception of our own body, also known as body image, can influence body-scaled actions. Certain conditions such as obesity are frequently accompanied by a negative body image, leaving open the question if body-scaled actions are distorted in these individuals.

METHODS

To shed light on this issue, we asked individuals affected by obesity to process dimensions of their own body in a real action: they walked in a straight-ahead direction, while avoiding collision with obstacles represented by door-like openings that varied in width.

RESULTS

Participants affected by obesity showed a body rotation behavior similar to that of the healthy weighted, but differences emerged in parameters such as step length and velocity.

CONCLUSION

When participants with obesity walk through door-like openings, their body parts rotation is scaled according to their physical body dimensions; however, they might try to minimize risk of collision. Our study is in line with the hypothesis that unconscious body-scaled actions are related to emotional, cognitive and perceptual components of a negative body image.

Two colliding epidemics - obesity is independently associated with chronic pain interfering with activities of daily living in adults 18 years and over; a cross-sectional, population-based study

BACKGROUND

Chronic pain interfering with activities of daily living is highly prevalent in the community. More than 600 million people worldwide are obese. The aim of this paper is to assess if such chronic pain is associated independently with obesity across the adult population, having controlled for other key factors.

METHODS

The South Australian Health Omnibus is an annual, population-based, cross-sectional study. Data on 2616 participants were analysed for episodes of daily pain for three of the preceding six months. Obesity was derived from self-reported height and weight. Multivariable logistic regression analysed the associations between chronic pain interfering with activities of daily living, body mass index (BMI) and key socio-demographic factors.

RESULTS

Chronic pain interfering with activities of daily living peaks in people ≥75 years of age while obesity peaks in the 45-54 age group. Pain and obesity together peak in the 55-74 year age group. In the adjusted multinominal logistic regression model, compared to those with no pain, there was a strong association between obesity and pain that interfered moderately or extremely with day-to-day activities (OR 2.25; 95 % CI 1.57-3.23; p < 0.001) having controlled for respondents' age, gender, rurality, country of birth and highest educational attainment. People over 65 years of age and those with lower educational levels were more likely to experience such chronic pain related to obesity.

CONCLUSION

This study demonstrates a strong association between chronic pain and obesity/morbid obesity in the South Australian population. Prospective, longitudinal data are needed to understand the dynamic interaction between these two prevalent conditions.

Pain Intensity and Pain Interference in Older Adults: Role of Gender, Obesity and High-Sensitivity C-Reactive Protein

BACKGROUND

Among older adults, pain intensity and pain interference are more common in women than men and associated with obesity and inflammatory markers.

OBJECTIVE

We examined whether the obesity and pain relationship is mediated by the high-sensitivity C-reactive protein (hsCRP), a nonspecific marker of systemic inflammation, and whether this relationship differs by sex.

METHODS

Items from Medical Outcomes Study Short Form-36 were used to measure pain intensity and pain interference in daily life. Ordinal logistic regression was used to assess the cross-sectional association among body mass index (BMI), hsCRP levels, pain intensity and pain interference using gender-stratified models adjusted for demographic variables.

RESULTS

Participants included 667 community-residing adults over the age of 70 years, free of dementia, enrolled in the Einstein Aging Study (EAS). In women (n = 410), pain intensity was associated with obesity [BMI ≥30 vs. normal, odds ratio (OR) = 2.29, 95% confidence interval (CI) 1.43-3.68] and higher hsCRP (OR = 1.28, 95% CI 1.08-1.51). In a model with obesity and hsCRP, both remained significant, but the association between hsCRP and pain intensity was somewhat attenuated. Obesity (OR = 3.04, 95% CI 1.81-5.11) and higher hsCRP levels (OR = 1.30, 95% CI 1.08-1.56) were also independently associated with greater pain interference in women. After adjustment for pain intensity and BMI, hsCRP was no longer associated with pain interference in women. Greater pain intensity and being overweight or obese continued to be significantly associated with pain interference in women. In men (n = 257), obesity and hsCRP were not associated with pain intensity or pain interference.

CONCLUSIONS

In women, the relationship between obesity and higher levels of pain intensity or interference may be accounted for by factors related to hsCRP.

Weight-loss interventions for overweight/obese adults with chronic musculoskeletal pain: a mixed methods systematic review protocol

REVIEW QUESTION/OBJECTIVE

The objective of this mixed methods review is to develop an aggregated synthesis of qualitative and quantitative data on weight-loss interventions for overweight/obese adults with chronic musculoskeletal pain in an attempt to derive conclusions and recommendations useful for clinical practice and policy decision making.The objective of the quantitative component of this review is to quantify the effectiveness of weight-loss interventions on weight, pain and physical and/or psychosocial function in overweight/obese adults with chronic musculoskeletal pain.The objectives of the qualitative component of this review are to explore the perceptions and experiences of overweight/obese adults with chronic musculoskeletal pain of the link between their weight and pain, and the effectiveness and appropriateness of weight-loss interventions and sustainability of weight-loss efforts.

Obesity and chronic pain: systematic review of prevalence and implications for pain practice

The combination of obesity and pain may worsen a patient's functional status and quality of life more than each condition in isolation. We systematically searched PubMed/MEDLINE and the Cochrane databases for all reports published on obesity and pain. The prevalence of combined obesity and pain was substantial. Good evidence shows that weight reduction can alleviate pain and diminish pain-related functional impairment. However, inadequate pain control can be a barrier to effective lifestyle modification and rehabilitation. This article examines specific pain management approaches for obese patients and reviews novel interventional techniques for treatment of obesity. The infrastructure for simultaneous treatment of obesity and pain already exists in pain medicine (eg, patient education, behavioral medicine approaches, physical rehabilitation, medications, and interventional treatment). Screening for obesity, pain-related disability, and behavioral disorders as well as monitoring of functional performance should become routine in pain medicine practices. Such an approach requires additional physician and staff training. Further research should focus on better understanding the interplay between these 2 very common conditions and the development of effective treatment strategies.

Obesity and pain

Recent reports suggest that almost half of the UK population is expected to be obese by 2030. A number of associations between obesity and chronic pain have been displayed in previous studies, and therefore it can be expected that the presentation of obese patients with chronic pain will rise in accordance with the prevalence of obesity. No single causative relationship between the two can be suggested, so the link between them is believed to be multifactorial. Despite this, little work has been done to draw together the many associations between obesity and pain. A better understanding of their connection, then, is required to appropriately manage this patient group that is increasing in numbers. This article aims to draw together existing evidence on the associations between obesity and pain to create a model of their multifactorial relationship. The article will systematically address each of the current theories in order to gradually build a diagrammatic representation of the relationship, which shall conclude the article.

Effective components of exercise and physical activity-related behaviour-change interventions for chronic non-communicable diseases in Africa: protocol for a systematic mixed studies review with meta-analysis

INTRODUCTION

Chronic non-communicable diseases (NCDs) account for a high burden of mortality and morbidity in Africa. Evidence-based clinical guidelines recommend exercise training and promotion of physical activity behaviour changes to control NCDs. Developing such interventions in Africa requires an understanding of the essential components that make them effective in this context. This is a protocol for a systematic mixed studies review that aims to determine the effective components of exercise and physical activity-related behaviour-change interventions for chronic diseases in Africa, by combining quantitative and qualitative research evidence from studies published until July 2015.

METHODS AND ANALYSIS

We will conduct a detailed search to identify all published and unpublished studies that assessed the effects of exercise and physical activity-related interventions or the experiences/perspectives of patients to these interventions for NCDs from bibliographic databases and the grey literature. Bibliographic databases include MEDLINE, EMBASE, CENTRAL (Cochrane Central Register of Controlled Trials), PsycINFO, CINAHL and Web of Science. We will include the following African regional databases: African Index Medicus (AIM) and AFROLIB, which is the WHO's regional office database for Africa. The databases will be searched from inception until 18 July 2015. Appraisal of study quality will be performed after results synthesis. Data synthesis will be performed independently for quantitative and qualitative data using a mixed methods sequential explanatory synthesis for systematic mixed studies reviews. Meta-analysis will be conducted for the quantitative studies, and thematic synthesis for qualitative studies and qualitative results from the non-controlled observational studies. The primary outcome will include exercise adherence and physical activity behaviour changes. This review protocol is reported according to Preferred Reporting Items for Systematic reviews and Meta-Analysis protocols (PRISMA-P) 2015 guidelines.

ETHICS AND DISSEMINATION

There is no ethical requirement for this study, as it utilises published data. This review is expected to inform the development of exercise and physical activity-related behaviour-change interventions in Africa, and will be presented at conferences, and published in peer reviewed journals and a PhD thesis at King's College London.

PROTOCOL REGISTRATION NUMBER

This study was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on 22 January 2015 (registration number: PROSPERO 2015: CRD42015016084).

Pain in Canadian Veterans: analysis of data from the Survey on Transition to Civilian Life

In the United States, extensive research has been conducted investigating chronic pain among Veterans; however, such research has not been conducted among Canadians who served in the military. Accordingly, this study aimed to investigate the prevalence of chronic pain among Canadian Veterans, and to determine correlates of chronic pain in this population. Data for this study were obtained from the Survey on Transition to Civilian Life; 3154 Veterans released from service between January 1, 1998 and December 31, 2007 responded to the survey.

BACKGROUND:

Little is known about the prevalence of chronic pain among Veterans outside the United States.

OBJECTIVE:

To describe the prevalence of chronic pain and associated sociodemographic, health behaviour, employment/income, disability, and physical and mental health factors in Canadian Veterans.

METHODS:

The 2010 Survey on Transition to Civilian Life included a nationally representative sample of 3154 Canadian Armed Forces Regular Force Veterans released from service between 1998 and 2007. Data from a telephone survey of Veterans were linked with Department of National Defence and Veterans Affairs Canada administrative databases. Pain was defined as constant/reoccurring pain (chronic pain) and as moderate/severe pain interference with activities.

RESULTS:

Forty-one percent of the population experienced constant chronic pain and 23% experienced intermittent chronic pain. Twenty-five percent reported pain interference. Needing help with tasks of daily living, back problems, arthritis, gastrointestinal conditions and age ≥30 years were independently associated with chronic pain. Needing help with tasks of daily living, back problems, arthritis, mental health conditions, age ≥30 years, gastrointestinal conditions, low social support and noncommissioned member rank were associated with pain interference.

CONCLUSIONS:

These findings provide evidence for agencies and those supporting the well-being of Veterans, and inform longitudinal studies to better understand the determinants and life course effects of chronic pain in military Veterans.

Tactile mental body parts representation in obesity

Obese people׳s distortions in visually-based mental body-parts representations have been reported in previous studies, but other sensory modalities have largely been neglected. In the present study, we investigated possible differences in tactilely-based body-parts representation between an obese and a healthy-weight group; additionally we explore the possible relationship between the tactile- and the visually-based body representation. Participants were asked to estimate the distance between two tactile stimuli that were simultaneously administered on the arm or on the abdomen, in the absence of visual input. The visually-based body-parts representation was investigated by a visual imagery method in which subjects were instructed to compare the horizontal extension of body part pairs. According to the results, the obese participants overestimated the size of the tactilely-perceived distances more than the healthy-weight group when the arm, and not the abdomen, was stimulated. Moreover, they reported a lower level of accuracy than did the healthy-weight group when estimating horizontal distances relative to their bodies, confirming an inappropriate visually-based mental body representation. Our results imply that body representation disturbance in obese people is not limited to the visual mental domain, but it spreads to the tactilely perceived distances. The inaccuracy was not a generalized tendency but was body-part related.