Mental stress and psychosocial factors at work in relation to multiple-site musculoskeletal pain: a longitudinal study of kitchen workers.

Among 385 female kitchen workers, we examined (1) whether mental stress and psychosocial factors at work (job control, skill discretion, supervisor support, co-worker relationships, and hurry) predict multiple-site musculoskeletal pain (MSP; defined as pain at ≥ 3 of seven sites) and (2) reversedly, whether MSP predicts these psychosocial factors. Data were collected by questionnaire at 3-month intervals during 2 years. Trajectory analysis was applied. Four trajectories of MSP prevalence emerged: Low, Descending, Ascending, and High. For the psychosocial factors, a two-trajectory model (Ascending or High vs. Low) yielded the best fit. In logistic regression analysis, with the Low MSP trajectory as reference, poor co-worker relationships (odds ratio [OR] 3.9), mental stress (3.1) and hurry (2.1) at baseline predicted belonging to the High MSP trajectory. Also MSP at baseline predicted the trajectories (Ascending vs. Low) of low job control (2.2) and mental stress (3.2). Adverse changes in most psychosocial factors were associated with belonging to the High (ORs between 2.3 and 8.6) and Ascending (2.7-5.5) MSP trajectories. In generalized estimating equations, time-lagged by 3 months, all psychosocial factors but two predicted MSP (1.4-2.1), allowing, e.g. for MSP at baseline, and vice versa, MSP predicted low job control, low supervisor support, and mental stress (1.4-2.0), after adjustment for e.g. the relevant psychosocial factor at baseline. In conclusion, we found that several psychosocial factors predicted MSP and that MSP predicted several psychosocial factors. The results suggest a cumulative process in which adverse psychosocial factors and MSP influence each other.

Effect of a participatory ergonomics intervention on psychosocial factors at work in a randomised controlled trial.

OBJECTIVES: To study the effect of a participatory ergonomics intervention on psychosocial factors among kitchen workers. DESIGN: A cluster randomised controlled trial. SETTING: Four cities in Finland, 2002-2005. PARTICIPANTS: 504 workers in 119 municipal kitchens. INTERVENTION: Kitchens were randomised to intervention (n=59) and control (n=60) groups. The intervention lasted 11-14 months and was based on the workers' active participation in work analysis, planning and implementing the ergonomic changes aimed at decreasing the physical and mental workload. MAIN OUTCOME MEASURES: Mental stress, mental strenuousness of work, hurry, job satisfaction, job control, skill discretion, co-worker relationships and supervisor support. Data were collected by questionnaire at baseline, at the end of the intervention, and at a 12-month follow-up (PI(12)). RESULTS: At the end of the intervention, the OR of job dissatisfaction for the intervention group as compared with the control group was 3.0 (95% CI 1.1 to 8.5), of mental stress 2.3 (1.2 to 4.7) and of poor co-worker relationships 2.3 (1.0 to 5.2). At the PI(12), the OR of job dissatisfaction was 3.0 (1.2 to 7.8). Analysis of the independent and joint effects of the intervention and unconnected organisational reforms showed that adverse changes were accentuated among those with exposure to both. CONCLUSIONS: No favourable effects on psychosocial factors at work were found. The adverse changes were due to a joint effect of the intervention and the unconnected organisational reforms. The findings do not support the usefulness of this kind of intervention in changing unsatisfactory psychosocial working conditions.

Association between interleukin 1 gene cluster polymorphisms and bilateral distal interphalangeal osteoarthritis.

OBJECTIVE: To examine the association of the interleukin 1 gene (IL1) cluster polymorphisms and their haplotypes with bilateral distal interphalangeal joint osteoarthritis (DIP OA). METHODS: Radiographs of both hands of 295 dentists and 248 teachers were examined and classified for the presence of OA using reference images. Bilateral DIP OA was defined by the presence of radiographic findings of grade 2 or more in at least 1 symmetrical pair of the DIP joints. We genotyped 10 single-nucleotide polymorphisms (SNP) in the IL1R1, IL1RL2, IL1A, IL1B, and IL1RN genes using polymerase chain reaction-based methods. Haplotypes were statistically reconstructed using the PHASE program. The association between the genotypes/diplotypes and bilateral DIP OA was examined with logistic regression analysis. RESULTS: Two IL1B SNP (rs1143634 and rs1143633) were associated with bilateral DIP OA. The carriers of the IL1B rs1143634 minor allele had an increased OA risk [odds ratio (OR) 1.6; 95% confidence interval (CI) 1.08-2.26] compared to the noncarriers. The association was stronger in the dentists. The distribution of the IL1B rs1143633 genotype fit a recessive mode of inheritance (OR 3.03, 95% CI 1.35-6.83, p = 0.006). Two IL1B-IL1RN extended haplotype alleles (211-1 and 121-1) were associated with bilateral DIP OA. An interaction between the IL1B rs1143634 and the IL1R1-IL1RL2 and IL1B-IL1RN extended haplotypes and occupation (increased risk of OA among dentists only) was observed. CONCLUSION: Our results provide further evidence for the role of IL1 gene cluster polymorphisms in the etiology of OA and suggest that some of these may predispose DIP joints to the effects of mechanical overload.

Modic changes and interleukin 1 gene locus polymorphisms in occupational cohort of middle-aged men.

According to recent systematic reviews, Modic changes are associated with low-back pain. However, their pathophysiology remains largely unknown. A previous study of Northern Finnish males implicated that IL1A and MMP3 polymorphisms play a role in type II Modic changes. The purpose of the current study was to examine the association of IL1 cluster polymorphisms with Modic changes amongst middle-aged men in Southern Finland. The final study sample consisted of 108 men from three different occupations, who underwent magnetic resonance imaging (MRI) with a 0.1 T-scanner. Six single nucleotide polymorphisms (SNP) in the IL1 gene cluster (IL1A c.1-889C>T; IL1B c.3954C>T; IL1RN c.1812G>A; IL1RN c.1887G>C; IL1RN c.11100T>C; IL1RN c.1506G>A) were genotyped with the SNP-TRAP method or by allele-specific primer extension on modified microarray. In all, 45 subjects had Modic changes at one or more disc levels. The presence of the minor allele of IL1A (c.1-889C>T) was associated with these changes (any Modic change p = 0.031, type II changes p = 0.036). The carriers of the T-allele had a 2.5-fold risk of Modic change and the association was independent of the other IL1 gene cluster loci studied. In addition, a minor haplotype, with a frequency of 7.5% in the study population, including the minor alleles of IL1A c.1-889C>T, IL1RN c.1812G>A, and IL1RN c.1506G>A, was significantly associated with Modic changes. This observation is in accordance with the previous finding from a different geographical area, and thus confirms the importance of the IL1A gene in the pathophysiology of Modic changes.

Evaluation of a participatory ergonomic intervention process in kitchen work.

We evaluated a participatory ergonomic intervention process applied in 59 municipal kitchens. In groups of three to five kitchens, the workers participated in eight workshops, and generated and evaluated solutions to optimize musculoskeletal load in their work. An ergonomist initiated and supported the process. By the end, 402 changes were implemented. Evaluative data were collected using research diaries, questionnaires, and focus group interviews. The intervention model proved feasible and the participatory approach was mostly experienced as motivating. The workers' knowledge and awareness of ergonomics increased, which improved their ability to tackle ergonomic problems by themselves. The changes in ergonomics were perceived to decrease physical load and improve musculoskeletal health. As hindering factors for implementation, lack of time and motivation, and insufficient financial resources were mentioned. In addition, the workers expressed a wish for more support from the management, technical staff, and ergonomists.

Common interleukin-6 promoter variants associate with the more severe forms of distal interphalangeal osteoarthritis.

INTRODUCTION: The objective of this study was to investigate the relationship of the IL-6 promoter variants G-597A, G-572C and G-174C (rs1800797, rs1800796 and rs1800795, respectively), which have been shown to affect both the transcription and secretion of IL-6, to symptomatic distal interphalangeal (DIP) osteoarthritis (OA). METHODS: A total of 535 women aged 45 to 63 years were included. Radiographs of both hands were taken and each DIP joint was evaluated (grade 0 to 4) for the presence of OA. Information on symptoms (pain, tenderness) in each joint was collected by using a self-administered questionnaire. Symptomatic DIP OA was defined by the presence of both radiographic findings of grade 2 or more and symptoms in at least two DIP joints, and symmetrical DIP OA by the presence of radiographic findings of grade 2 or more in at least one symmetrical pair of DIP joints. Common polymorphic loci in the IL-6 gene were amplified and the promoter haplotypes were reconstructed from genotype data with the PHASE program. Logistic regression analysis was used to examine the association between the IL-6 genotypes/diplotypes and the DIP OA outcome. RESULTS: The G alleles of two promoter single nucleotide polymorphisms (SNPs) G-597A and G-174C were more common among the subjects with symptomatic DIP OA than among those with no disease (P = 0.020 and 0.024, corrected for multiple testing). In addition, the carriage of at least one G allele in these positions increased the risk of disease (P = 0.006 and P = 0.008, respectively). Carrying a haplotype with the G allele in all three promoter SNPs increased the risk of symptomatic DIP OA more than fourfold (odds ratio (OR) 4.45, P = 0.001). Carriage of the G-G diplotype indicated an increased risk of both symmetrical DIP OA (OR 1.52, 95% confidence interval 1.01 to 2.28) and symptomatic DIP OA (OR 3.67, 95% confidence interval 1.50 to 9.00). CONCLUSION: The present study showed that the presence of G alleles at common IL-6 polymorphic promoter loci was associated with the more severe DIP OA outcomes, symmetrical and symptomatic.

Effectiveness of early part-time sick leave in musculoskeletal disorders.

BACKGROUND: The importance of staying active instead of bed rest has been acknowledged in the management of musculoskeletal disorders (MSDs). This emphasizes the potential benefits of adjusting work to fit the employee's remaining work ability. Despite part-time sick leave being an official option in many countries, its effectiveness has not been studied yet. We have designed a randomized controlled study to assess the health effects of early part-time sick leave compared to conventional full-day sick leave. Our hypothesis is that if work time is temporarily reduced and work load adjusted at the early stages of disability, employees with MSDs will have less disability days and faster return to regular work duties than employees on a conventional sick leave. METHODS/DESIGN: The study population will consist of 600 employees, who seek medical advice from an occupational physician due to musculoskeletal pain. The inclusion requires that they have not been on a sick leave for longer than 14 days prior to the visit. Based on the physician's judgement, the severity of the symptoms must indicate a need for conventional sick leave, but the employee is considered to be able to work part-time without any additional risk. Half of the employees are randomly allocated to part-time sick leave group and their work time is reduced by 40-60%, whereas in the control group work load is totally eliminated with conventional sick leave. The main outcomes are the number of days from the initial visit to return to regular work activities, and the total number of sick leave days during 12 and 24 months of follow-up. The costs and benefits as well as the feasibility of early part-time sick leave will also be evaluated. CONCLUSION: This is the first randomised trial to our knowledge on the effectiveness of early part-time sick leave compared to conventional full-time sick leave in the management of MSDs. The data collection continues until 2011, but preliminary results on the feasibility of part-time sick leave will be available already in 2008. The increased knowledge will assist in better decision making process regarding the management of disability related to MSDs. TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number Register, register number ISRCTN30911719.

Occupational loading, health behavior and sleep disturbance as predictors of low-back pain.

OBJECTIVES: Risk factors for low-back pain are known to co-occur, but their joint effect has not often been studied. Little is also known about the variation of the risk factors or their effects with age. METHODS: This prospective study assessed the 1-year incidence of low-back pain by age group in a Finnish industrial population. The effects of the baseline variables on the risk of low-back pain in the follow-up were estimated with a log-binomial regression. RESULTS: Among 2256 blue- and white-collar workers free of low-back pain 12 months preceding the baseline, 21% reported low-back pain after 1-year of follow-up. Physical work load (sum of heavy lifting, awkward postures, and whole-body vibration) predicted low-back pain among those younger than 50 years [highest relative risk (RR) 2.4, 95% confidence interval (95% CI) 1.4-4.2], whereas health behavior (sum of smoking, overweight, and lack of physical exercise) increased the risk only among those 50 years or older (RR up to 2.8, 95% CI 1.4-5.4). Mental stress, dissatisfaction with life, and sleep problems were significant predictors in the group of 40- to 49-year-old workers. Work-related psychosocial factors were not associated with the outcome. CONCLUSIONS: In this study, workers of different ages were affected by slightly different risk factors. The results support the provision of health promotion and stress management as part of programs to prevent work-related low-back pain. In particular, aging workers may benefit from such an integrated approach. More prospective studies on the joint effects of age-specific risk factors of low-back pain are warranted.

Association between the aggrecan gene variable number of tandem repeats polymorphism and intervertebral disc degeneration.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: To examine the association between an aggrecan variable number of tandem repeats (VNTR) polymorphism and intervertebral disc degeneration in middle-aged Finnish men. SUMMARY OF BACKGROUND DATA: An association between the aggrecan VNTR polymorphism and multilevel disc degeneration has been previously reported in young Japanese women. METHODS: Lumbar discs of 132 men representing 3 occupations (carpenters, machine drivers, and office workers) were evaluated on magnetic resonance imaging, using decreased signal intensity of the nucleus pulposus, disc bulges, and decreased disc height as signs of degeneration. The aggrecan gene VNTR region was analyzed by Southern hybridization. RESULTS: The allele A26 with 26 repeats was statistically significantly overrepresented among the persons with dark nucleus pulposus. Carrying 2 copies of the A26 allele increased the risk of dark nucleus pulposus (odds ratio = 2.77; 95% confidence interval, 1.24-6.16). Carrying the alleles with either less or more than 26 repeats decreased the risk of dark nucleus pulposus. The carpenters and machine drivers with the A26 allele had a statistically significantly higher risk of disc bulge and decreased disc height than the office workers without the allele. CONCLUSION: The findings provide additional support for the role of the aggrecan gene VNTR polymorphism in intervertebral disc degeneration.

Co-occurrence of musculoskeletal pain among female kitchen workers.

OBJECTIVES: The co-occurrence of musculoskeletal pain symptoms in seven body sites and their combinations among women in kitchen work were studied. METHODS: Data on musculoskeletal pain during the past 3 months in the neck, shoulders, forearms/hands, low back, hips, knees and ankles/feet were gathered by questionnaire from 495 female workers (mean age 45 years) in connection with an ergonomic intervention study in municipal kitchens of four cities in Finland. Altogether 122 kitchens (60% of those eligible) participated in the study. The response rate in the participating kitchens was 98%. RESULTS: The 3-month prevalence of any musculoskeletal pain was 87%, the most common sites being the neck (71%), low back (50%) and forearms/hands (49%). About 73% of the subjects had pain in at least two, 36% in four or more, and 10% in 6-7 sites. In pair wise comparisons, e.g. neck pain was associated with pain in other sites with prevalence ratios (PR) varying from 1.3 to 1.6, and ankle or foot pain with ratios between 1.9 and 2.4. The seven pain symptoms occurred in more than 80 different combinations. When the co-occurrence of pain was studied in three larger anatomical areas, i.e. any pain in the axial (neck and low back), upper limb and lower limb areas, subjects reporting concurrent pain in all three were the largest category (36% of the respondents). Altogether 53% of the workers reported pain in at least the axial and upper limb areas, and 48% in at least the axial and lower limb areas. CONCLUSIONS: Widespread co-occurrence of musculoskeletal pain symptoms was common among female kitchen workers with slight predominance in the upper body.

Serum lipids and low back pain: an association? A follow-up study of a working population sample.

STUDY DESIGN: Cohort study with 5-, 10-, and 28-year follow-up. OBJECTIVES: To examine associations between baseline serum lipid concentrations and later low back pain (LBP). SUMMARY OF BACKGROUND DATA: Atherosclerosis of the lumbar vessels has been suggested as a mechanism leading to disc degeneration and LBP. Cholesterol is considered essential for atherosclerosis development. METHODS: A sample (n = 902) of employees in an engineering company was examined for serum total cholesterol and triglycerides, body mass index (BMI), smoking, exercise, work history, and LBP in 1973. By November 2000, 232 subjects had died. In 1978, 748 (84% of the survivors), in 1983, 654 (76%), and in 2000, 546 (81%) responded to a follow-up questionnaire. RESULTS: In men, baseline serum total cholesterol predicted new cases of radiating LBP in the 5-year follow-up (highest tertile vs. lowest: odds ratio [OR], 2.5; 95% confidence interval [CI], 1.1-5.9) and in the 10-year follow-up (OR, 2.8; 95% CI, 1.3-6.1), adjusted for age, occupational class, work history, BMI, smoking and exercise. Also, serum triglycerides predicted new cases in the latter examination (OR, 2.6; 95% CI, 1.2-5.8). In women, no associations were seen until the 10-year follow-up, when their results were similar to those in men. In the total material, serum total cholesterol predicted radiating LBP reported both at the 10- and the 28-year follow-up. CONCLUSIONS: High serum lipids predicted incident radiating LBP, consistent with the atherosclerosis-LBP hypothesis.

Cardiovascular risk factors and low-back pain in a long-term follow-up of industrial employees.

OBJECTIVES: Atherosclerosis of the lumbar vessels has been suggested as a mechanism leading to low-back pain (LBP). We studied whether seven cardiovascular disease (CVD) risk factors predict LBP. METHODS: A sample (N=902) stratified by gender, age, and occupational class was drawn from employees in an engineering company in 1973 and examined for body mass index (BMI), smoking, exercise, serum total cholesterol and triglyceride concentrations, systolic blood pressure (SBP), diastolic blood pressure (DBP), and LBP. By November 2000, 232 persons had died, 108 from cardiovascular causes. In 2000, 546 (81% of the survivors) responded to a follow-up questionnaire on, for example, LBP. RESULTS: Among the men, frequent local LBP at follow-up was predicted by high triglyceride and DBP levels and being a past smoker at baseline, adjusted for age, occupational class and frequent local LBP at baseline. In analogous models, high triglyceride and SBP levels and smoking (past and current) predicted frequent radiating LBP. An increased LBP score was predicted by a high BMI, serum total cholesterol, triglyceride, SBP and DBP levels, and smoking status at baseline. When BMI was allowed for, the associations between triglyceride level and all LBP outcomes persisted, as well as the association between SBP and frequent radiating LBP and an increased LBP score. An overall score of CVD risk factors showed a graded association with increased LBP. Among the women, a high BMI predicted frequent local and radiating LBP, and smoking at baseline predicted frequent radiating LBP and an increased LBP score. CONCLUSIONS: The study adds to the evidence supporting the atherosclerosis-LBP hypothesis particularly for men.

Vitamin D receptor gene polymorphisms and susceptibility of hand osteoarthritis in Finnish women.

We examined whether polymorphisms of the vitamin D receptor (VDR) gene was associated with individual risk of hand osteoarthritis (OA). Radiographs of both hands of 295 dentists and of 248 teachers were examined and classified for the presence of OA using reference images. The VDR ApaI and TaqI genotypes were determined by PCR-based methods. No association was observed between the VDR polymorphisms and the odds of overall hand OA. However, the carriers of the VDR t allele or At haplotype were at almost half the odds of symmetrical hand OA (odds ratio [OR] = 0.60, 95% confidence interval [CI] = 0.38-0.94 and OR = 0.59, 95% CI = 0.38-0.93, respectively) compared with the carriers of the T allele and of the non-At haplotype, respectively. Increased odds of this disease, on the contrary, was observed for women with two copies of the VDR a allele (OR = 1.93, 95% CI = 1.99-3.70) compared with women with the AA genotype. Conversely, the VDR a allele carriage was associated with a tendency of lowered odds of osteophyte (OR = 0.51, 95% CI = 0.25-1.03). When the genotype data were used to construct haplotypes, the VDR AaTt joint genotype appeared to pose a remarkably lower odds (OR = 0.26, 95% CI = 0.08-0.91) of osteophyte compared with the AAtt joint genotype. As a novel finding we observed a joint effect of a low calcium intake and VDR polymorphisms on symmetrical OA; the OR was 2.64 (95% CI = 1.29-5.40) for carriers of the aT haplotype with low daily calcium intake compared with non-carriers of the haplotype with high daily calcium intake. Our results suggest that VDR gene polymorphisms play a role in the etiology of symmetrical hand OA. Moreover, the association between the VDR gene and OA may be modified by calcium intake.

Sleep disturbances as predictors of hospitalization for back disorders-a 28-year follow-up of industrial employees.

STUDY DESIGN: A prospective cohort study. OBJECTIVE: To study the relationship of sleep disturbances with severe back disorders leading to hospitalization. SUMMARY OF BACKGROUND DATA: Sleep disturbances are associated with persistent pain syndromes, but little is known about their relationship with back disorders. METHODS: The first hospital admission for back disorders from 1973 to 2000 was studied in a cohort of metal industry workers (n = 902). The occurrence of sleep disturbances at baseline was categorized as: none; 1 type (either difficulties in falling asleep/waking up at night or nightmares); or both types. Cox proportional hazards regression was used to estimate the time between the assessment of risk factors and first hospital admission for back disorders. RESULTS: Those individuals who had 1 type of sleep disturbance had a 2.1-fold (95% confidence interval 1.1-3.8) risk of back-related hospitalization, and those with both types of disturbance a 2.4-fold (1.2-4.6) risk, compared with those with no sleep disturbances. The hazard ratios were 2.1; 1.0-4.6 and 2.9; 1.2-7.1, respectively, when patients with chronic back disease or recurrent back symptoms at baseline were excluded from the analyses. CONCLUSION: These findings suggest that sleep disturbances are predictive of hospitalization for back disorders. The mechanism underlying this association warrants further study.

Persistence of low back pain reporting among a cohort of employees in a metal corporation: a study with 5-, 10-, and 28-year follow-ups.

Low back pain (LBP) is a common symptom among adults but little is known about its persistence over time in defined populations. The aim of this study was to examine the persistence of LBP among a cohort of industrial employees studied in four successive surveys during a total of 28 years. Cross-tabulations and logistic regression was used to estimate the interdependence of LBP occurrence at the surveys. At baseline, 54% of the subjects reported local LBP and 25% LBP radiating to the lower limb(s). Persistent or recurrent LBP was common. Of those with LBP at baseline, 75, 73, and 88% reported it also at the 5-, 10- or 28-year follow-up, respectively. Of those with radiating pain, 66, 65, and 69% were symptomatic 5, 10, or 28 years later. The onset of reporting LBP increased during follow-up. Of those without local LBP at baseline, 33, 37 and 64% had pain at the 5-, 10-, or 28-year follow-up, respectively. Of those without radiating LBP, 17, 22, and 46% had pain at the 5-, 10-, or 28-year follow-up. The odds ratio of local LBP at the 5-, 10-, or 28-year follow-up for those with such pain at baseline vs. not were 6.0 (95% CI 4.3-8.3), 4.7 (3.3-6.6) and 4.0 (2.6-6.3), adjusted for age, gender and occupational class. The respective figures for radiating LBP were 8.5 (5.7-12.5), 6.7 (4.4-10.1) and 2.3 (1.5-3.6). We conclude that LBP is commonly recurrent.

Intervertebral disc degeneration in relation to the COL9A3 and the IL-1ss gene polymorphisms.

Disc degeneration is a complex condition in which environmental factors and multiple genes are expected to act together to determine the degenerative phenotype. Recently associations of COL9A2 (Trp2 allele) and COL9A3 (Trp3 allele) polymorphisms with lumbar disc disease characterized by sciatica have been reported. However, it is not known whether the Trp2 or Trp3 alleles contribute to disc degeneration (DD). In this study, the association between the collagen genes polymorphisms and lumbar DD was investigated. Furthermore, the influence of the IL-1beta(C(3954)-T) polymorphism on the association of collagen genes polymorphisms with DD was examined. Lumbar intervertebral discs of 135 middle-aged occupationally active men were evaluated with magnetic resonance imaging, using decreased signal intensity of the nucleus pulposus, disc bulges, and decreased disc height as signs of degeneration. Blood samples were analysed for the presence of COL9A3 and COL9A2 tryptophan alleles (Trp3 and Trp2 alleles). The COL11A2, COL2A1 and IL-1beta(C(3954)-T) polymorphisms were also analysed. Multivariate logistic regression analysis allowing for occupation and body mass index showed that the carriage of the Trp3 allele in the absence of the IL-1betaT(3954) allele increased the risk of dark nucleus pulposus (OR 7.0, 95% CI 1.3-38.8) and joint occurrence of degenerative changes (OR 8.0, 95% CI 1.4-44.7). There was no effect of the Trp3 allele on DD in the presence of the IL-1betaT(3954) allele. The carriers of the COL11A2 minor allele had an increased risk of disc bulges (OR 2.1, 95% CI 1.0-4.2) as compared with non-carriers. The results suggest that the effect of the COL9A3 gene polymorphism on DD might be modified by the IL-1beta gene polymorphism.

Low back pain among nurses: a follow-up beginning at entry to the nursing school.

STUDY DESIGN: A prospective cohort. OBJECTIVES: To investigate the prevalence of back pain from entering the nursing school through 5 years in nursing and the determinants and modifiers of back pain and disability. SUMMARY OF BACKGROUND DATA: Physical loading, psychologic characteristics, and several other factors have been associated with back pain at work in earlier studies. Because of the lack of the prework entry morbidity data, the nature of the associations between these exposures and the symptoms is unclear. That previous back pain is a predictor of later pain underlines the importance to have pre-employment data in investigations of the role of exposures at work. METHODS: Female nursing students (n = 174) were followed for 7.5 years. Data on constitutional and behavioral factors, occupational exposures, and back-related symptoms and disability were collected. Back pain was grouped into "sciatic," "sudden," or "other" and related disability. RESULTS: The lifetime cumulative prevalence of back pain increased from 31% at entry to nursing school to 72% at the end of the school and further to 82% after 5 years as a nurse. The 1-year prevalence of any back pain was 54% for the first year in nursing school, 57% for the first year as a nurse, and 64% for the fifth year as a nurse. In multivariate analyses, other back pain and related disability as a nurse were associated with back pain history at the entry to nursing school (odds ratio, 7.1; 95% confidence interval, 1.5-34; and 3.6; 1.2-11, respectively), and working in twisted/bent positions (odds ratio, 6.2; 95% confidence interval, 1.7-23; and 7.5; 2.9-20, respectively). Sudden back pain was not associated with any of the studied risk factors. Sciatic back pain was associated only with working positions (odds ratio, 6.9; 95% confidence interval, 2.1-23). CONCLUSIONS: Lifetime prevalence of back pain increased sharply during nursing school but slowly after that. Back pain at entering the nursing school was a predictor for back-related pain and disability. Self- reported occupational physical work load was associated with back pain and related disability. The nature of the association is unclear, but it is likely that back pain is exacerbated during nursing.

Respiratory symptoms and diseases among construction painters.

OBJECTIVE: To study the self-reported prevalence of respiratory symptoms and diseases among construction painters and estimate the potential risk for this group compared with a representative group of carpenters sharing the construction work environment but without significant exposure to paint. METHODS: A questionnaire study was conducted on 1,000 male Finnish construction painters and 1,000 carpenters (mean response rate 60.5%). Symptoms and diseases of the respiratory tract were studied, by logistic regression modelling, in relation to occupation and duration of painting experience. Age, atopy and smoking habits were taken into account. RESULTS: The painters reported more asthma-like, rhinitis, laryngeal and eye symptoms than the carpenters [odds ratio (OR) 1.4-1.8]. The difference in the prevalence of asthma between the occupations was not statistically significant, but the painters with 1-10 years of painting experience had a threefold risk of asthma compared with the carpenters. Chronic bronchitis was linked to painting occupation [OR 1.9, 95% confidence interval (CI) 1.2-3.0] and to the duration of exposure; OR (CI) for over 30 years of painting was 2.2 (1.2-4.0). Occupation was not associated with allergic rhinitis or conjunctivitis. CONCLUSIONS: The results indicate a higher risk for respiratory symptoms and chronic bronchitis among construction painters than among carpenters.

Low back pain, work absenteeism, chronic back disorders, and clinical findings in the low back as predictors of hospitalization due to low back disorders: a 28-year follow-up of industrial employees.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To study symptoms, chronic disorders, and clinical findings in the low back, and work absenteeism, as predictors of hospitalization. SUMMARY OF BACKGROUND DATA: Socioeconomic and lifestyle factors are associated with back-related hospitalization, but the significance in the working normal population of low back symptoms and clinical findings are not known. METHODS: The cohort (n = 902) was drawn in 1973 from among employees in the metal industry (n = 2,653). The data were collected by questionnaire and a structured clinical assessment by a physiotherapist. Weight was measured. A sum score of local and radiating low back symptoms (frequency during the past year on a 4-point Likert scale) was categorized as no/yes and no/infrequent/frequent. Local and radiating symptoms were considered also separately. The data were linked with those from the Finnish Hospital Discharge Register during 1973 to 2000. Logistic regression and the Cox proportional hazard models were used. RESULTS: As compared with persons without low back pain, those with frequent or radiating low back pain had an increased risk of hospitalization due to low back disorders (hazard rate ratio (HRR), 3.0; 95% confidence interval (CI), 1.4-6.5, and 3.7; 1.8-7.7, respectively) after adjustment for age, gender, and occupational class. Similarly, clinical findings (HRR, 2.4; 95% CI, 1.3-4.7), back-related absenteeism (HRR, 3.3; 95% CI, 1.6-6.7), and chronic low back disorders (HRR, 2.8; 95% CI, 1.5-5.4) predicted hospitalization. The associations persisted when further adjusted for smoking, body mass index, and distress symptoms at baseline. CONCLUSION: Frequent or radiating low back symptoms, chronic low back disorders, back-related work absenteeism, and having clinical findings in the low back predicted inpatient hospital care for low back disorders.

A population study on differences in the determinants of a specific shoulder disorder versus nonspecific shoulder pain without clinical findings.

Musculoskeletal pain frequently occurs without particular clinical findings. Pain per se may be determined by factors other than those indicating a clinical disorder. The authors examined the prevalence and determinants of clinically diagnosed chronic rotator cuff tendinitis and self-reported nonspecific shoulder pain. The Health 2000 survey, carried out in 2000-2001 in Finland, included a nationally representative sample of 8,028 persons aged 30 years or more. In the present study, analyses were restricted to subjects aged 30-64 years who had held a job during the preceding 12 months. The prevalences of chronic rotator cuff tendinitis and nonspecific shoulder pain were 2.0% (78 of 3,909 subjects) and 12% (410 of 3,525 subjects), respectively. Nonspecific pain was related to burnout (adjusted odds ratio (OR) = 1.7, 95% confidence interval (CI): 1.4, 2.2), depression (among women, the adjusted OR was 1.8 (95% CI: 1.1, 2.9) for mild depression and 3.0 (95% CI: 1.6, 5.6) for severe depression), and inability to express one's feelings (alexithymia) (adjusted OR = 1.6, 95% CI: 1.1, 2.5). However, these factors were not associated with chronic rotator cuff tendinitis, determinants of which were work-related cumulative loading on the shoulder, age, and insulin-dependent diabetes mellitus (adjusted OR = 8.8, 95% CI: 1.9, 40.3). The determinants of specific musculoskeletal disorders differ from those of subjective complaints without clinical findings. Such complaints may be indicators of adverse psychological and psychosocial factors rather than the presence of an underlying pathologic condition.