Descriptive epidemiology of somatising tendency: findings from the CUPID study.

Somatising tendency, defined as a predisposition to worry about common somatic symptoms, is importantly associated with various aspects of health and health-related behaviour, including musculoskeletal pain and associated disability. To explore its epidemiological characteristics, and how it can be specified most efficiently, we analysed data from an international longitudinal study. A baseline questionnaire, which included questions from the Brief Symptom Inventory about seven common symptoms, was completed by 12,072 participants aged 20-59 from 46 occupational groups in 18 countries (response rate 70%). The seven symptoms were all mutually associated (odds ratios for pairwise associations 3.4 to 9.3), and each contributed to a measure of somatising tendency that exhibited an exposure-response relationship both with multi-site pain (prevalence rate ratios up to six), and also with sickness absence for non-musculoskeletal reasons. In most participants, the level of somatising tendency was little changed when reassessed after a mean interval of 14 months (75% having a change of 0 or 1 in their symptom count), although the specific symptoms reported at follow-up often differed from those at baseline. Somatising tendency was more common in women than men, especially at older ages, and varied markedly across the 46 occupational groups studied, with higher rates in South and Central America. It was weakly associated with smoking, but not with level of education. Our study supports the use of questions from the Brief Symptom Inventory as a method for measuring somatising tendency, and suggests that in adults of working age, it is a fairly stable trait

Musculoskeletal disorders and associated factors in nurses and bank workers in South Africa

A thesis submitted to the faculty of Health Sciences, University of Witwatersrand, in fulfilment of the requirements for the degree of Doctor of Philosophy Johannesburg, 2017Background Work has long been suspected of being involved in the genesis of musculoskeletal disorders. These disorders have been found to affect a significant proportion of the working population. Certain occupational groups across different industries are at a particular risk of musculoskeletal disorders possibly, due to the nature of their work, including nurses and bank workers. In South Africa, there is a paucity of information regarding musculoskeletal disorder risk factors in these two occupational groups. Additionally, no follow-up studies have been conducted to examine incident (new onset) and persistent pain and socio-cultural factors potentially associated with musculoskeletal pain. The research reported in this thesis was conducted in public hospital nurses and call centre bank workers. Objectives To determine the 12-month prevalences and body site localisation of reported musculoskeletal disorders in South African public hospital nurses and bank workers. To characterise the features and consequences of prevalent musculoskeletal disorders in South African public hospital nurses and bank workers. To identify the risk factors associated with prevalent musculoskeletal disorders in South African public hospital nurses and bank workers. To determine incident and persistent musculoskeletal disorders in South African public hospital nurses. To identify the risk factors associated with persistent musculoskeletal disorders in South African public hospital nurses. Methods The study had a baseline cross-sectional component which included both nurses and bank workers and a follow-up component ranging from 11.2-13.0 months from baseline which covered nurses. The main data collection tools were the modified CUPID baseline and follow-up questionnaires which were composites of standardised and validated instruments. Since the questionnaires were written in English, the baseline questionnaire was piloted in a suitable group of workers not earmarked for the study, for clarity and comprehension of questions and the time it would take to administer one questionnaire. After making the necessary changes, the baseline questionnaire was administered through interviews to 488 South African workers comprising 252 nurses and 236 bank workers who provided informed consent to participate in the study. Information about demographic characteristics, potential musculoskeletal disorder risk factors and occurrence of musculoskeletal disorders and their associated consequences was collected. At follow-up, 189 nurses (75.3%) who had participated at baseline were successfully re-interviewed about the occurrence of musculoskeletal disorders a month before the follow-up period. The collected data were cleaned and prepared for analysis. Descriptive statistics were generated followed by the selection of explanatory variables to be included in the multiple logistic regression. These variables were used to build partial models with age group, sex and occupational group. Variables with p-values ≤ 0.2 were viii selected for the full models. The full models were run to produce final models which contained variables with p-values < 0.05. Results Prevalence and characteristics of musculoskeletal disorders in South African workers, public hospital nurses, and bank workers The estimated 12-month prevalences (95% CI) of musculoskeletal disorders reported by the South African workers, public hospital nurses, and bank workers were high at 80.5% (77.0%-84.0%), 84.1% (79.5%-88.6%) and 76.7% (71.3%-82.1%), respectively. The most prevalent pain was in the low back (56.9%, 58.2% and 55.5%) and the least prevalent in the elbows (14.3%, 13.2% and 15 7%). More than half (58.6%, 64.9% and 51.4%) of the workers who reported pain in different body sites consulted healthcare providers for pain. Conservative estimates of sick leave days taken by each worker in the past 12 months due to musculoskeletal disorder pain were 2.2, 2.4 and 1.9 days for all workers, nurses and bank workers, respectively. Risk factors for musculoskeletal disorders in South African workers, public hospital nurses and bank workers Somatising tendency In South African workers, somatising tendency was associated with the reporting of pain in all body sites considered in the study. The associations with pain in “any” body site ORs (95% CI) 2.23 (1.15-4.31); 3.52 (1.84-6.72) and low back 1.81 (1.07-3.03); 2.72 (1.69-4.40), demonstrated increasing trends when the effect of one and two distressing somatic symptoms was compared to no symptoms, respectively. In public hospital nurses, it was associated with pain in four body sites which included “any” body site 6.58 (1.76-24.47) and knees 2.80 (1.33-5.86) and in bank workers, in six body sites which included “any” body site 3.17 (1.40-7.19) and low back 2.56 (1.22-5.36) when the effect of two or more distressing somatic symptoms was compared to no symptoms. Sex “Women” in South African workers and bank workers was associated with pain in the upper limbs constituted by shoulders 1.83 (1.04-3.37); 1.90 (1.01-3.59) and wrists or hands 2.28 (1.09-4.74); 2.53 (1.11-5.75) compared to men, respectively. Age group In South African workers, age groups (40-49 and ≥50 years) demonstrated increasing trends with pain in the shoulders 2.23 (1.27-3.90); 2.40 (1.21-4.79) and knees 2.18 (1.16-4.09); 2.50 (1.16-5.38), respectively. In public hospital nurses, age group (40-49 years) was associated with pain in the shoulders 4.70 (1.15-19.10) and age group (≥50 years) with pain in “any” body site 2.67 (1.09-6.54). In bank workers, an increasing trend with age groups (40-49 and ≥50 years) was demonstrated with pain in the knees 2.91 (1.19-7.10) and 4.04 (1.32-12.38), respectively. The effect of each age group was compared to <30 years age group. Occupational group Occupational group (bank workers) was associated with pain in the neck 1.66 (1.04-2.67) but no positive association was found with pain in “any” body site 0.51 (0.27-0.96) compared to nurses. Incident and persistent musculoskeletal disorders in public hospital nurses Incident “any” musculoskeletal disorders (95% CI) were estimated at 47.6% (36.5%-58.6%) with incident low back pain affecting the largest percentage of nurses (32.8%) and incident elbow pain (8.5%) the lowest. Persistent “any” musculoskeletal disorders (95% CI) were estimated at 83.7% (76.2%-91.1%) with persistent knee pain affecting most nurses (71.4%) and persistent elbow pain the least number of nurses (36.4%). Risk factor for persistent musculoskeletal disorders in public hospital nurses Somatising tendency was associated with persistent pain in “any" body site 7.32 (1.34-39.88) when the effect of two or more distressing somatic symptoms was compared to no symptoms. Ethnicity Ethnic group was associated with wrists or hands and low back. In all workers, Nguni and “other” ethnic groups were associated with wrists or hands 1.85 (1.08-3.18); 2.02 (1.09-3.72) and in bank workers 3.75 (1.41-9.97); 2.87 (1.13-7.28), respectively. In nurses, the “other” ethnic group was associated with wrists or hands 2.81 (1.07-7.39). In all workers, “other” ethnic group was associated with low back 1.86 (1.07-3.34) and in bank workers 2.43 (1.16-5.08). The effect of ethnic groups was compared to the Sotho group. Conclusions The study found a high burden of musculoskeletal disorders in the two groups of workers studied with pain in the low back being the most prevalent. The large proportions of workers, who consulted healthcare providers and took time off from work due to musculoskeletal disorders, indicate the negative impact that these disorders may have on the affected workers and their places of work. The main risk factors emerging from this research belong to the individual dimension of musculo-skeletal disorder risk factors. This may signal their importance in the development and persistence of these disorders. Furthermore, they may need to be considered in any effort to address musculoskeletal disorders in the groups of workers studied. This study failed to provide convincing evidence of association between ethnicity and musculoskeletal disorders in the groups studied.MT201

Patterns of change of multisite pain over 1 year of follow-up and related risk factors

Background: multisite musculoskeletal pain is common and disabling. This study aimed to prospectively investigate the distribution of musculoskeletal pain anatomically, and explore risk factors for increases/reductions in the number of painful sites.Methods: using data from participants working in 45 occupational groups in 18 countries, we explored changes in reporting pain at 10 anatomical sites on two occasions 14 months apart. We used descriptive statistics to explore consistency over time in the number of painful sites, and their anatomical distribution. Baseline risk factors for increases/reductions by ≥3 painful sites were explored by random intercept logistic regression that adjusted for baseline number of painful sites.Results: among 8927 workers, only 20% reported no pain at either time point, and 16% reported ≥3 painful sites both times. After 14 months, the anatomical distribution of pain often changed but there was only an average increase of 0.17 painful sites. Some 14% workers reported a change in painful sites by ≥3. Risk factors for an increase of ≥3 painful sites included female sex, lower educational attainment, having a physically demanding job and adverse beliefs about the work-relatedness of musculoskeletal pain. Also predictives were as follows: older age, somatizing tendency and poorer mental health (each of which was also associated with lower odds of reductions of ≥3 painful sites).Conclusions: longitudinally, the number of reported painful sites was relatively stable but the anatomical distribution varied considerably. These findings suggest an important role for central pain sensitization mechanisms, rather than localized risk factors, among working adults.Significance: our findings indicate that within individuals, the number of painful sites is fairly constant over time, but the anatomical distribution varies, supporting the theory that among people at work, musculoskeletal pain is driven more by factors that predispose to experiencing or reporting pain rather than by localized stressors specific to only one or two anatomical sites

The CUPID (Cultural and Psychosocial Influences on Disability) study: methods of data collection and characteristics of study sample

Background: The CUPID (Cultural and Psychosocial Influences on Disability) study was established to explore the hypothesis that common musculoskeletal disorders (MSDs) and associated disability are importantly influenced by culturally determined health beliefs and expectations. This paper describes the methods of data collection and various characteristics of the study sample.Methods/Principal Findings: standardised questionnaire covering musculoskeletal symptoms, disability and potential risk factors, was used to collect information from 47 samples of nurses, office workers, and other (mostly manual) workers in 18 countries from six continents. In addition, local investigators provided data on economic aspects of employment for each occupational group. Participation exceeded 80% in 33 of the 47 occupational groups, and after pre-specified exclusions, analysis was based on 12,426 subjects (92 to 1018 per occupational group). As expected, there was high usage of computer keyboards by office workers, while nurses had the highest prevalence of heavy manual lifting in all but one country. There was substantial heterogeneity between occupational groups in economic and psychosocial aspects of work; three- to five-fold variation in awareness of someone outside work with musculoskeletal pain; and more than ten-fold variation in the prevalence of adverse health beliefs about back and arm pain, and in awareness of terms such as “repetitive strain injury” (RSI).Conclusions/Significance: the large differences in psychosocial risk factors (including knowledge and beliefs about MSDs) between occupational groups should allow the study hypothesis to be addressed effectivel

Epidemiological differences between localized and non-localized low back pain

Study Design. A cross-sectional survey with a longitudinal follow-up.Objectives. The aim of this study was to test the hypothesis that pain, which is localized to the low back, differs epidemiologically from that which occurs simultaneously or close in time to pain at other anatomical sitesSummary of Background Data. Low back pain (LBP) often occurs in combination with other regional pain, with which it shares similar psychological and psychosocial risk factors. However, few previous epidemiological studies of LBP have distinguished pain that is confined to the low back from that which occurs as part of a wider distribution of pain.Methods. We analyzed data from CUPID, a cohort study that used baseline and follow-up questionnaires to collect information about musculoskeletal pain, associated disability, and potential risk factors, in 47 occupational groups (office workers, nurses, and others) from 18 countries.Results. Among 12,197 subjects at baseline, 609 (4.9%) reported localized LBP in the past month, and 3820 (31.3%) nonlocalized LBP. Nonlocalized LBP was more frequently associated with sciatica in the past month (48.1% vs. 30.0% of cases), occurred on more days in the past month and past year, was more often disabling for everyday activities (64.1% vs. 47.3% of cases), and had more frequently led to medical consultation and sickness absence from work. It was also more often persistent when participants were followed up after a mean of 14 months (65.6% vs. 54.1% of cases). In adjusted Poisson regression analyses, nonlocalized LBP was differentially associated with risk factors, particularly female sex, older age, and somatizing tendency. There were also marked differences in the relative prevalence of localized and nonlocalized LBP by occupational group.Conclusion. Future epidemiological studies should distinguish where possible between pain that is limited to the low back and LBP that occurs in association with pain at other anatomical locations.Level of Evidence:

Patterns of multi-site pain and associations with risk factors

To explore definitions for multisite pain, and compare associations with risk factors for different patterns of musculoskeletal pain, we analysed cross-sectional data from the Cultural and Psychosocial Influences on Disability study. The study sample comprised 12,410 adults aged 20-59years from 47 occupational groups in 18 countries. A standardised questionnaire was used to collect information about pain in the past month at each of 10 anatomical sites, and about potential risk factors. Associations with pain outcomes were assessed by Poisson regression, and characterised by prevalence rate ratios (PRRs). Extensive pain, affecting 6-10 anatomical sites, was reported much more frequently than would be expected if the occurrence of pain at each site were independent (674 participants vs 41.9 expected). In comparison with pain involving only 1-3 sites, it showed much stronger associations (relative to no pain) with risk factors such as female sex (PRR 1.6 vs 1.1), older age (PRR 2.6 vs 1.1), somatising tendency (PRR 4.6 vs 1.3), and exposure to multiple physically stressing occupational activities (PRR 5.0 vs 1.4). After adjustment for number of sites with pain, these risk factors showed no additional association with a distribution of pain that was widespread according to the frequently used American College of Rheumatology criteria. Our analysis supports the classification of pain at multiple anatomical sites simply by the number of sites affected, and suggests that extensive pain differs importantly in its associations with risk factors from pain that is limited to only a small number of anatomical sites.<br/

Determinants of international variation in the prevalence of disabling wrist and hand pain

BACKGROUND: Previous research has indicated that wide international variation in the prevalence of disabling low back pain among working populations is largely driven by factors predisposing to musculoskeletal pain more generally. This paper explores whether the same applies to disabling wrist/hand pain (WHP). METHODS: Using data from the Cultural and Psychosocial Influences on Disability (CUPID) study, we focused on workers from 45 occupational groups (office workers, nurses and other workers) in 18 countries. Among 11,740 participants who completed a baseline questionnaire about musculoskeletal pain and potential risk factors, 9082 (77%) answered a further questionnaire after a mean interval of 14 months, including 1373 (15%) who reported disabling WHP in the month before follow-up. Poisson regression was used to assess associations of this outcome with baseline risk factors, including the number of anatomical sites other than wrist/hand that had been painful in the 12 months before baseline (taken as an index of general propensity to pain). RESULTS: After allowance for other risk factors, the strongest associations were with general pain propensity (prevalence rate ratio for an index ≥6 vs. 0: 3.6, 95% confidence interval 2.9-4.4), and risk rose progressively as the index increased. The population attributable fraction for a pain propensity index > 0 was 49.4%. The prevalence of disabling WHP by occupational group ranged from 0.3 to 36.2%, and correlated strongly with mean pain propensity index (correlation coefficient 0.86). CONCLUSION: Strategies to prevent disability from WHP among working populations should explore ways of reducing general propensity to pain, as well as improving the ergonomics of occupational tasks

Epidemiological differences between localized and nonlocalized low back pain.

STUDY DESIGN: A cross-sectional survey with a longitudinal follow-up. OBJECTIVES: The aim of this study was to test the hypothesis that pain, which is localized to the low back, differs epidemiologically from that which occurs simultaneously or close in time to pain at other anatomical sites SUMMARY OF BACKGROUND DATA.: Low back pain (LBP) often occurs in combination with other regional pain, with which it shares similar psychological and psychosocial risk factors. However, few previous epidemiological studies of LBP have distinguished pain that is confined to the low back from that which occurs as part of a wider distribution of pain. METHODS: We analyzed data from CUPID, a cohort study that used baseline and follow-up questionnaires to collect information about musculoskeletal pain, associated disability, and potential risk factors, in 47 occupational groups (office workers, nurses, and others) from 18 countries. RESULTS: Among 12,197 subjects at baseline, 609 (4.9%) reported localized LBP in the past month, and 3820 (31.3%) nonlocalized LBP. Nonlocalized LBP was more frequently associated with sciatica in the past month (48.1% vs. 30.0% of cases), occurred on more days in the past month and past year, was more often disabling for everyday activities (64.1% vs. 47.3% of cases), and had more frequently led to medical consultation and sickness absence from work. It was also more often persistent when participants were followed up after a mean of 14 months (65.6% vs. 54.1% of cases). In adjusted Poisson regression analyses, nonlocalized LBP was differentially associated with risk factors, particularly female sex, older age, and somatizing tendency. There were also marked differences in the relative prevalence of localized and nonlocalized LBP by occupational group. CONCLUSION: Future epidemiological studies should distinguish where possible between pain that is limited to the low back and LBP that occurs in association with pain at other anatomical locations. LEVEL OF EVIDENCE: 2