Software-recorded and self-reported duration of computer use in relation to the onset of severe arm–wrist–hand pain and neck–shoulder pain

Objectives: In both science and media, the adverse effects of a long duration of computer use at work on musculoskeletal health have long been debated. Until recently, the duration of computer use was mainly measured by self-reports, and studies using more objective measures, such as software-recorded computer duration, were lacking. The objective of this study was to examine the association between duration of computer use at work, measured with software and self-reports, and the onset of severe arm-wrist-hand and neck-shoulder symptoms. Methods: A 2-year follow-up study was conducted between 2004 and 2006 among 1951 office workers in The Netherlands. Self-reported computer duration and other risk factors were collected at baseline and at 1-year follow-up. Computer use at work was recorded continuously with computer software for 1009 participants. Outcome questionnaires were obtained at baseline and every 3 months during follow-up. Cases were identified based on the transition within 3 months of no or minor symptoms to severe symptoms. Results: Self-reported duration of computer use was positively associated with the onset of both arm-wrist-hand (RR 1.9, 95% CI 1.1 to 3.1 for more than 4 h/day of total computer use at work) and neck-shoulder symptoms (RR 1.5, 95% CI 1.1 to 2.0 for more than 4 h/day of mouse use at work). The recorded duration of computer use did not show any statistically significant association with the outcomes. Conclusions: In the present study, no association was found between the software-recorded duration of computer use at work and the onset of severe arm-wrist-hand and neck-shoulder symptoms using an exposure window of 3 months. In contrast, a positive association was found between the self-reported duration of computer use at work and the onset of severe arm-wrist-hand and neck-shoulder symptoms. The different findings for recorded and self-reported computer duration could not be explained satisfactorily

Loss of Productivity Due to Neck/Shoulder Symptoms and Hand/Arm Symptoms: Results from the PROMO-Study

Introduction: The objective of the present study is to describe the extent of productivity loss among computer workers with neck/shoulder symptoms and hand/arm symptoms, and to examine associations between pain intensity, various physical and psychosocial factors and productivity loss in computer workers with neck/shoulder and hand/arm symptoms. Methods: A cross-sectional design was used. The study population consisted of 654 computer workers with neck/shoulder or hand/arm symptoms from five different companies. Descriptive statistics were used to describe the occurrence of self-reported productivity loss. Logistic regression analyses were used to examine the associations. Results: In 26% of all the cases reporting symptoms, productivity loss was involved, the most often in cases reporting both symptoms (36%). Productivity loss involved sickness absence in 11% of the arm/hand cases, 32% of the neck/shoulder cases and 43% of the cases reporting both symptoms. The multivariate analyses showed statistically significant odds ratios for pain intensity (OR: 1.26; CI: 1.12-1.41), for high effort/no low reward (OR: 2.26; CI: 1.24-4.12), for high effort/low reward (OR: 1.95; CI: 1.09-3.50), and for low job satisfaction (OR: 3.10; CI: 1.44-6.67). Physical activity in leisure time, full-time work and overcommitment were not associated with productivity loss. Conclusion: In most computer workers with neck/shoulder symptoms or hand/arm symptoms productivity loss derives from a decreased performance at work and not from sickness absence. Favorable psychosocial work characteristics might prevent productivity loss in symptomatic workers. © 2007 Springer Science+Business Media, LLC

Plasma cadmium is associated with increased risk of long-term kidney graft failure

The kidney is one of the most sensitive organs to cadmium-induced toxicity, particularly in conditions of long-term oxidative stress. We hypothesized that, in kidney transplant recipients, nephrotoxic exposure to cadmium represents an overlooked hazard for optimal graft function. To test this, we performed a prospective cohort study and included 672 outpatient kidney transplant recipients with a functioning graft of beyond one year. The median plasma cadmium was 58 ng/L. During a median 4.9 years of follow-up, 78 kidney transplant recipients developed graft failure with a significantly different distribution across tertiles of plasma cadmium (13, 26, and 39 events, respectively). Plasma cadmium was associated with an increased risk of graft failure (hazard ratio 1.96, 95% confidence interval 1.56-2.47 per log(2) ng/L). Similarly, a dose-response relationship was observed over increasing tertiles of plasma cadmium, after adjustments for potential confounders (donor, recipient, transplant and lifestyle characteristics), robust in both competing risk and sensitivity analyses. These findings were also consistent for kidney function decline (graft failure or doubling of serum creatinine). Thus, plasma cadmium is independently associated with an increased risk of long-term kidney graft failure and decline in kidney function. Further studies are needed to investigate whether exposure to cadmium represents an otherwise overlooked modifiable risk factor for adverse long-term graft outcomes in different populations

Selenium and outcome in heart failure

Aims: Severe deficiency of the essential trace element selenium can cause myocardial dysfunction although the mechanism at cellular level is uncertain. Whether, in clinical practice, moderate selenium deficiency is associated with worse symptoms and outcome in patients with heart failure is unknown. Methods and results: BIOSTAT‐CHF is a multinational, prospective, observational cohort study that enrolled patients with worsening heart failure. Serum concentrations of selenium were measured by inductively coupled plasma mass spectrometry. Primary endpoint was a composite of all‐cause mortality and hospitalization for heart failure; secondary endpoint was all‐cause mortality. To investigate potential mechanisms by which selenium deficiency might affect prognosis, human cardiomyocytes were cultured in absence of selenium, and mitochondrial function and oxidative stress were assessed. Serum selenium concentration (deficiency) was <70 μg/L in 485 (20.4%) patients, who were older, more often women, had worse New York Heart Association class, more severe signs and symptoms of heart failure and poorer exercise capacity (6‐min walking test) and quality of life (Kansas City Cardiomyopathy Questionnaire). Selenium deficiency was associated with higher rates of the primary endpoint [hazard ratio (HR) 1.23; 95% confidence interval (CI) 1.06–1.42] and all‐cause mortality (HR 1.52; 95% CI 1.26–1.86). In cultured human cardiomyocytes, selenium deprivation impaired mitochondrial function and oxidative phosphorylation, and increased intracellular reactive oxygen species levels. Conclusions: Selenium deficiency in heart failure patients is independently associated with impaired exercise tolerance and a 50% higher mortality rate, and impaired mitochondrial function in vitro, in human cardiomyocytes. Clinical trials are needed to investigate the effect of selenium supplements in patients with heart failure, especially if they have low plasma concentrations of selenium

Prospective research on musculoskeletal disorders in office workers (PROMO): study protocol

BACKGROUND: This article describes the background and study design of the PROMO study (Prospective Research on Musculoskeletal disorders in Office workers). Few longitudinal studies have been performed to investigate the risk factors responsible for the incidence of hand, arm, shoulder and neck symptoms among office workers, given the observation that a large group of office workers might be at risk worldwide. Therefore, the PROMO study was designed. The main aim is to quantify the contribution of exposure to occupational computer use to the incidence of hand, arm, shoulder and neck symptoms. The results of this study might lead to more effective and/or cost-efficient preventive interventions among office workers. METHODS/DESIGN: A prospective cohort study is conducted, with a follow-up of 24 months. In total, 1821 participants filled out the first questionnaire (response rate of 74%). Data on exposure and outcome is collected using web-based self-reports. Outcome assessment takes place every three months during the follow-up period. Data on computer use are collected at baseline and continuously during follow-up using a software program. DISCUSSION: The advantages of the PROMO study include the long follow-up period, the repeated measurement of both exposure and outcome, and the objective measurement of the duration of computer use. In the PROMO study, hypotheses stemming from lab-based and field-based research will be investigated

Test-retest reliability and validity of self-reported duration of computer use at work

This study evaluated the test–retest reliability and the validity of self-reported duration of computer use at work. Test–retest reliability was studied among 81 employees of a research department of a university medical center. The employees filled out a web-based questionnaire twice with an in-between period of 14 days. Validity was studied among a group of 572 office workers who participated in an epidemiologic field study. A software program recorded the duration of computer use at work during the 3 months preceding the questionnaire. The percentages of agreement for test–retest reliability were 75% [95% confidence interval (95% CI) 64–84] for total computer use and 67% (95% CI 55–77) for mouse use. The percentages of agreement between self-report and registration were 18% (95% CI 15–21) for total computer use and 16% (95% CI 13–19) for mouse use. Misclassification was mainly nondifferential in nature, since all of the evaluated subgroups showed at least 75% misclassification. It is concluded that the use of self-reports lead to the misclassification of exposure to computer use for more than 80% of all persons. This misclassification is predominantly nondifferential in nature and can only partly be explained by limited test–retest reliability