Poul Frost

Aarhus University Hospital, Aarhus, Central Jutland, Denmark

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Publications (58)163.87 Total impact

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    ABSTRACT: Study Design A prospective cohort study nested in a randomized controlled trial. Objectives To determine and compare responsiveness and minimal clinically important change (MCIC) of the modified Constant Score (CS) and the Oxford Shoulder Score (OSS). Background The OSS and the CS are commonly used to assess shoulder outcomes. However, measurement properties in terms of responsiveness and MCIC have been sparsely evaluated. Methods The study included 126 patients with difficulty returning to usual activities 8-12 weeks after arthroscopic decompression surgery for subacromial impingement syndrome. The assessment at baseline and 3 months included the OSS, the CS, and the EQ-5D-3L index. Responsiveness was assessed in three ways: by correlation analysis between change scores of the two shoulder scores and the EQ-5D-3L index and Patients' Global Impression of Change (PGIC), receiver operating characteristics (ROC) curve analysis using the PGIC as an external anchor, and effect size (ES) statistics. Results At 3 months, 112 patients were followed up. The change scores of the CS and the OSS were more strongly correlated with the external anchor (PGIC) than those of the EQ-5D-3L index. The area under the ROC curves exceeded 0.80 for both shoulder scores, with no significant differences between them, and comparable ES estimates were observed for the CS and the OSS. MCICROC values were 6 points for the OSS and 11 points for the CS, with upper 95% cut off limits of 12 and 22 points, respectively. Conclusion The CS and the OSS were both suitable for assessing improvement after decompression surgery. J Orthop Sports Phys Ther, Epub 25 Jun 2015. doi:10.2519/jospt.2015.5760.
    No preview · Article · Jun 2015
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    Full-text · Article · May 2015 · Physiotherapy
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    ABSTRACT: Background: Rotator cuff tendinopathy including tears is a cause of significant morbidity. The molecular pathogenesis of the disorder is largely unknown. This review aimed to present an overview of the literature on gene expression and protein composition in human rotator cuff tendinopathy and other tendinopathies, and to evaluate perspectives of proteomics--the comprehensive study of protein composition--in tendon research. Materials and methods: We conducted a systematic search of the literature published between 1 January 1990 and 18 December 2012 in PubMed, Embase, and Web of Science. We included studies on objectively quantified differential gene expression and/or protein composition in human rotator cuff tendinopathy and other tendinopathies as compared to control tissue. Results: We identified 2199 studies, of which 54 were included; 25 studies focussed on rotator cuff or biceps tendinopathy. Most of the included studies quantified prespecified mRNA molecules and proteins using polymerase chain reactions and immunoassays, respectively. There was a tendency towards an increase of collagen I (11 of 15 studies) and III (13 of 14), metalloproteinase (MMP)-1 (6 of 12), -9 (7 of 7), -13 (4 of 7), tissue inhibitor of metalloproteinase (TIMP)-1 (4 of 7), and vascular endothelial growth factor (4 of 7), and a decrease in MMP-3 (10 of 12). Fourteen proteomics studies of tendon tissues/cells failed inclusion, mostly because they were conducted in animals or in vitro. Conclusions: Based on methods, which only allowed simultaneous quantification of a limited number of prespecified mRNA molecules or proteins, several proteins appeared to be differentially expressed/represented in rotator cuff tendinopathy and other tendinopathies. No proteomics studies fulfilled our inclusion criteria, although proteomics technologies may be a way to identify protein profiles (including non-prespecified proteins) that characterise specific tendon disorders or stages of tendinopathy. Thus, our results suggested an untapped potential for proteomics in tendon research.
    Full-text · Article · Apr 2015 · PLoS ONE
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    Full-text · Article · Apr 2015 · Hernia
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    ABSTRACT: Pain in more than one site is common in working populations. We aimed to characterise combined pain (pain in the upper and lower body) and to evaluate whether the prevalence of combined pain is positively related to combined occupational mechanical exposures to the upper and lower body and to high psychosocial job strain. This cross-sectional study was based on questionnaire data from the Musculoskeletal Research Database at the Danish Ramazzini Centre. The study included 14,081 men and 20,173 women. Occupational exposures were assessed by job exposure matrices. We analysed the prevalence of pain limited to the upper body, pain limited to the lower body, and combined pain in relation to occupational exposures using Poisson regression. During the last year, 23.2 % of the men and 33.9 % of the women reported combined pain, which was characterised by somatisation, illness worrying, and low SF-36 scores. For men, the adjusted prevalence ratio for combined pain was 1.51 [95 % confidence interval (95 % CI) 1.40-1.64] in relation to exposures limited to the upper body and 2.24 (95 % CI 2.11-2.39) in relation to combined exposures. For women, the corresponding adjusted prevalence ratios were 1.56 (95 % CI 1.50-1.63) and 1.55 (95 % CI 1.50-1.61). High job strain was related to pain among men, only. Combined pain may in part be explained by local effects of occupational mechanical exposures acting at more than one site.
    No preview · Article · Mar 2015 · International Archives of Occupational and Environmental Health
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    ABSTRACT: This paper describes the development and details of a standardised physiotherapy exercise intervention designed to address pain and disability in patients with difficulty returning to usual activities after arthroscopic decompression surgery for subacromial impingement syndrome. To develop the intervention, the literature was reviewed with respect to the effectiveness of postoperative exercises, components of previous exercise programmes were extracted, and input from clinical physiotherapists in the field was obtained through a series of workshops. The physiotherapy exercise intervention is currently being evaluated within the framework of the Shoulder Intervention Project (ISRCTN55768749). Copyright © 2015 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.
    No preview · Article · Jan 2015 · Physiotherapy
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    ABSTRACT: To evaluate if occupational mechanical exposures are associated with an increased risk of surgery for varicose veins (VV) in the lower extremities. We conducted a longitudinal study of persons from the Musculoskeletal Research Database at the Danish Ramazzini Centre who were 18-65 years old when they provided baseline questionnaire data during 1993-2004. Exposure estimates were obtained from a job exposure matrix based on expert ratings. The register information on first-time surgery for VV was retrieved. We used Cox regression analyses. During 416 317 person-years of follow-up among 38 036 persons, 851 first-time operations for VV occurred. Using standing/walking <4 h/day and uncommon lifting as references, exposure-response relationships with risk of surgery were found for men. For women, the risk increased too, but without clear exposure-response patterns. The adjusted HRs for ≥6 h/day spent standing/walking were 3.17 (95% CI 2.06 to 4.89) and 2.34 (95% CI 1.72 to 3.19) for men and women, respectively. For high lifting exposures (≥1000 kg/day), the adjusted HRs were 3.95 (95% CI 2.32 to 6.73) for men and 2.54 (95% CI 1.95 to 3.31) for women. Other risk factors were increasing age for men and parity for women. Minimal leisure-time physical activity, a high body mass index and smoking were not associated with increased risk. The results suggested an increased risk of surgery for VV in relation to prolonged standing/walking and heavy lifting and a preventive potential of more than 60% of all cases in exposed occupations. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
    No preview · Article · Jan 2015 · Occupational and Environmental Medicine
  • M V Vad · P Frost · S W Svendsen
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    ABSTRACT: The aim of this study was to evaluate exposure-response relationships between occupational mechanical exposures and risk of reoperation after inguinal hernia repair. Using register information, we identified all men born in Denmark 1938-1988, who had their first inguinal hernia repair 1998-2008, and who were 18-65 years old and active in the labour market at the time of surgery. The Danish Hernia Database provided information on repairs and reoperations. We used registered occupational codes and a job exposure matrix based on experts' ratings to estimate total load lifted per day, frequency of heavy lifting, and number of hours per day spent standing/walking. We also obtained register information on sickness absence. Multivariable Cox regression analysis was used. The cohort comprised 34,822 patients. We did not reveal exposure-response relationships between occupational mechanical exposures and the hazard ratio (HR) of reoperation. The percentage of patients with >2 weeks of sickness absence within 8 weeks after surgery increased with total load lifted per day from 15 to 53 %. Longer sickness absence was associated with an increased HR of reoperation, but within strata of sickness absence, we found no increase in the HR of reoperation with increasing exposures. We did not find indications that the HR of reoperation was related to occupational mechanical exposures, even after accounting for a potential protective effect of sickness absence. Hence, the exposure-related prolonged duration of sickness absence could not be explained by exposure-related complications that led to reoperation.
    No preview · Article · Dec 2014 · Hernia
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    ABSTRACT: Objective: To investigate the risk of total hip replacement (THR) due to primary osteoarthritis in relation to cumulative occupational mechanical exposures and lifestyle factors. Methods: Using register information, we identified first-time THR cases within the Danish working population in 2005-2006. For each case, 2 age- and sex-matched controls were drawn. Persons within 2,500 randomly selected case-control sets received a questionnaire about job history, weight at age 25 years, present weight and height, smoking, and sports activities at age 25 years. The job history was combined with a job exposure matrix. Cumulative exposure estimates were expressed according to the pack-year concept of smoking (e.g., cumulative lifting was expressed as ton-years). We used conditional logistic regression for statistical analyses. Results: In total, 1,776 case-control sets (71%) were available for analysis. The adjusted odds ratio (OR) for exposure to ≥20 ton-years was 1.35 (95% confidence interval [95% CI] 1.05-1.74) for men and 1.00 (95% CI 0.73-1.41) for women. Standing/walking and whole body vibration showed no associations. The adjusted OR for body mass index (BMI) ≥30 kg/m(2) at age 25 years was 2.44 (95% CI 1.38-4.32) for men and 5.12 (95% CI 2.30-11.39) for women. The corresponding adjusted ORs for an increase in BMI of ≥10 kg/m(2) since age 25 years were 2.16 (95% CI 1.25-3.70) and 2.46 (95% CI 1.47-4.13). Sports participation showed weak positive associations, while pack-years of smoking showed no associations. Conclusion: The results indicated a modest increase in risk of THR in relation to cumulative lifting among men and an increased risk in relation to a high BMI at age 25 years and to a gain in BMI in both sexes.
    No preview · Article · Oct 2014
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    ABSTRACT: Objectives The primary aim was to examine exposure–response relationships between cumulative occupational shoulder exposures and surgery for subacromial impingement syndrome (SIS), and to compare sex-specific exposure–response relationships. The secondary aim was to examine the time window of relevant exposures. Methods We conducted a nationwide register study of all persons born in Denmark (1933–1977), who had at least 5 years of full-time employment. In the follow-up period (2003–2008), we identified first-time events of surgery for SIS. Cumulative exposure estimates for a 10-year exposure time window with a 1-year lag time were obtained by linking occupational codes with a job exposure matrix. The exposure estimates were expressed as, for example, arm-elevation-years in accordance with the pack-year concept of tobacco consumption. We used a multivariable logistic regression technique equivalent to discrete survival analysis. Results The adjusted OR (ORadj) increased to a maximum of 2.1 for arm-elevation-years, repetition-years and force-years, and to 1.5 for hand-arm-vibration-years. Sex-specific exposure–response relationships were similar for men and women, when assessed using a relative risk scale. The ORadj increased gradually with the number of years contributing to the cumulative exposure estimates. The excess fraction was 24%. Conclusions Cumulative occupational shoulder exposures carried an increase in risk of surgery for SIS with similar exposure–response curves for men and women. The risk of surgery for SIS increased gradually, when the period of exposure assessment was extended. In the general working population, a substantial fraction of all first-time operations for SIS could be related to occupational exposures.
    Full-text · Article · Aug 2014 · Occupational and Environmental Medicine
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    ABSTRACT: Background Surgery for subacromial impingement syndrome is often performed in working age and postoperative physiotherapy exercises are widely used to help restore function. A recent Danish study showed that 10% of a nationwide cohort of patients retired prematurely within two years after surgery. Few studies have compared effects of different postoperative exercise programmes on shoulder function, and no studies have evaluated workplace-oriented interventions to reduce postoperative work disability. This study aims to evaluate the effectiveness of physiotherapy exercises and occupational medical assistance compared with usual care in improving shoulder function and reducing postoperative work disability after arthroscopic subacromial decompression. Methods/Design The study is a mainly pragmatic multicentre randomised controlled trial. The trial is embedded in a cohort study of shoulder patients referred to public departments of orthopaedic surgery in Central Denmark Region. Patients aged ≥18–≤63 years, who still have shoulder symptoms 8–12 weeks after surgery, constitute the study population. Around 130 participants are allocated to: 1) physiotherapy exercises, 2) occupational medical assistance, 3) physiotherapy exercises and occupational medical assistance, and 4) usual care. Intervention manuals allow individual tailoring. Primary outcome measures include Oxford Shoulder Score and sickness absence due to symptoms from the operated shoulder. Randomisation is computerised with allocation concealment by randomly permuted block sizes. Statistical analyses will primarily be performed according to the intention-to-treat principle. Discussion The paper presents the rationale, design, methods, and operational aspects of the Shoulder Intervention Project (SIP). SIP evaluates a new rehabilitation approach, where physiotherapy and occupational interventions are provided in continuity of surgical episodes of care. If successful, the project may serve as a model for rehabilitation of surgical shoulder patients. Trial registration Current Controlled Trials ISRCTN55768749.
    Full-text · Article · Jun 2014 · BMC Musculoskeletal Disorders
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    ABSTRACT: Background When conducting large scale epidemiologic studies, it is a challenge to obtain quantitative exposure estimates, which do not rely on self-report where estimates may be influenced by symptoms and knowledge of disease status. In this study we developed a job exposure matrix (JEM) for use in population studies of the work-relatedness of hip and knee osteoarthritis. Methods Based on all 2227 occupational titles in the Danish version of the International Standard Classification of Occupations (D-ISCO 88), we constructed 121 job groups comprising occupational titles with expected homogeneous exposure patterns in addition to a minimally exposed job group, which was not included in the JEM. The job groups were allocated the mean value of five experts’ ratings of daily duration (hours/day) of standing/walking, kneeling/squatting, and whole-body vibration as well as total load lifted (kg/day), and frequency of lifting loads weighing ≥20 kg (times/day). Weighted kappa statistics were used to evaluate inter-rater agreement on rankings of the job groups for four of these exposures (whole-body vibration could not be evaluated due to few exposed job groups). Two external experts checked the face validity of the rankings of the mean values. Results A JEM was constructed and English ISCO codes were provided where possible. The experts’ ratings showed fair to moderate agreement with respect to rankings of the job groups (mean weighted kappa values between 0.36 and 0.49). The external experts agreed on 586 of the 605 rankings. Conclusion The Lower Body JEM based on experts’ ratings was established. Experts agreed on rankings of the job groups, and rankings based on mean values were in accordance with the opinion of external experts.
    Full-text · Article · Jun 2014 · BMC Musculoskeletal Disorders
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    ABSTRACT: To investigate the risk of total hip replacement (THR) due to primary osteoarthritis (OA) in relation to cumulative occupational mechanical exposures and lifestyle factors.
    No preview · Article · Jun 2014 · Occupational and Environmental Medicine
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    ABSTRACT: We constructed a lower body job exposure matrix (JEM) based on five experts' assessments of occupational mechanical exposures. The aim of this study was to evaluate the face validity of the rankings of the job groups and the inter-rater agreement between the experts' rankings.
    No preview · Article · Jun 2014 · Occupational and Environmental Medicine
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    ABSTRACT: Controversies have long existed on causes for low back pain, and the role of occupational mechanical exposures, e.g. lifting has been debated for several decades. The aim of this study was to investigate if lifting is a risk factor for low back surgery.
    No preview · Article · Jun 2014 · Occupational and Environmental Medicine
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    ABSTRACT: To evaluate relations between occupational mechanical exposures and (1) carpal tunnel syndrome verified by ENG (ENG+CTS) and (2) CTS-like symptoms with normal ENG (ENG-CTS).
    No preview · Article · Jun 2014 · Occupational and Environmental Medicine
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    ABSTRACT: Little is known about the time window for accumulation of occupational exposures and shoulder disorders. We aimed to evaluate cumulative occupational shoulder exposures as risk factors for surgery for subacromial impingement syndrome (SIS), and to examine how long the relevant exposure time period is.
    No preview · Article · Jun 2014 · Occupational and Environmental Medicine
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    ABSTRACT: Little is known about the influence of occupational mechanical shoulder exposures on the development of acromioclavicular joint degeneration. We aimed to evaluate if arm elevation >90(o), force requirements, and repetitive work are associated with acromioclavicular joint degeneration as assessed by magnetic resonance imaging (MRI).
    No preview · Article · Jun 2014 · Occupational and Environmental Medicine
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    ABSTRACT: Introduction: We examined whether lifestyle factors differ between patients with ulnar neuropathy confirmed by electroneurography (ENG) and those with ulnar neuropathy-like symptoms with normal ulnar nerve ENG. Methods: Among patients examined by ENG for suspected ulnar neuropathy, we identified 546 patients with ulnar neuropathy and 633 patients with ulnar neuropathy-like symptoms. These groups were compared with 2 separate groups of matched community referents and to each other. Questionnaire information on lifestyle was obtained. The electrophysiological severity of neuropathy was also graded. We used conditional and unconditional logistic regression. Results: Responses were obtained from 59%. Ulnar neuropathy was related to smoking, adjusted odds ratio (OR) 4.31 (95% confidence interval [CI] 2.43-7.64) for >24 pack-years. Ulnar neuropathy-like symptoms were related to body mass index ≥30 kg/m(2), OR 1.99 (95% CI 1.25-3.19). Smoking was associated with increased severity of ulnar neuropathy. Conclusions: Findings suggest that smoking specifically affects the ulnar nerve.
    No preview · Article · Apr 2014 · Muscle & Nerve
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    ABSTRACT: We examined the association between occupational lifting during pregnancy and risk of fetal death and preterm birth using a job exposure matrix (JEM). For 68,086 occupationally active women in the Danish National Birth Cohort, interview information on occupational lifting was collected around gestational week 16. We established a JEM based on information from women, who were still pregnant when interviewed. The JEM provided mean total loads lifted per day within homogeneous exposure groups as informed by job and industry codes. All women were assigned an exposure estimate from the JEM. We used Cox regression models with gestational age as underlying time variable and adjustment for covariates. We observed 2,717 fetal deaths and 3,128 preterm births within the study cohort. No exposure-response relation was observed for fetal death, but for women with a prior fetal death, we found a hazard ratio (HR) of 2.87 (95% CI 1.37, 6.01) for stillbirth (fetal death ≥22 completed gestational weeks) among those who lifted >200 kg/day. For preterm birth, we found an exposure-response relation for primigravid women, reaching a HR of 1.43 (95% CI 1.13, 1.80) for total loads >200 kg per day. These findings correspond to an excess fraction of 11% for stillbirth and 10% for preterm birth. We found an increased risk of stillbirth among women with a prior fetal death, who lifted >200 kg/day, and an exposure-response relationship between occupational lifting and preterm birth among primigravid women. The study adds to a large body of prospective studies on occupational lifting and adverse pregnancy outcomes by refined exposure assessment.
    Preview · Article · Mar 2014 · PLoS ONE

Publication Stats

1k Citations
163.87 Total Impact Points

Institutions

  • 1998-2015
    • Aarhus University Hospital
      • Department of Occupational Medicine
      Aarhus, Central Jutland, Denmark
  • 2014
    • Herning Hospital
      Herning, Central Jutland, Denmark
  • 2012-2014
    • Danish Ramazzini Centre
      • Department of Occupational Medicine
      Ålborg, North Denmark, Denmark
  • 2011
    • Aarhus University
      Aarhus, Central Jutland, Denmark