Job strain in relation to body mass index: pooled analysis of 160 000 adults from 13 cohort studies.

BACKGROUND: Evidence of an association between job strain and obesity is inconsistent, mostly limited to small-scale studies, and does not distinguish between categories of underweight or obesity subclasses. OBJECTIVES: To examine the association between job strain and body mass index (BMI) in a large adult population. METHODS: We performed a pooled cross-sectional analysis based on individual-level data from 13 European studies resulting in a total of 161 746 participants (49% men, mean age, 43.7 years). Longitudinal analysis with a median follow-up of 4 years was possible for four cohort studies (n = 42 222). RESULTS: A total of 86 429 participants were of normal weight (BMI 18.5-24.9 kg m(-2) ), 2149 were underweight (BMI < 18.5 kg m(-2) ), 56 572 overweight (BMI 25.0-29.9 kg m(-2) ) and 13 523 class I (BMI 30-34.9 kg m(-2) ) and 3073 classes II/III (BMI ≥ 35 kg m(-2) ) obese. In addition, 27 010 (17%) participants reported job strain. In cross-sectional analyses, we found increased odds of job strain amongst underweight [odds ratio 1.12, 95% confidence interval (CI) 1.00-1.25], obese class I (odds ratio 1.07, 95% CI 1.02-1.12) and obese classes II/III participants (odds ratio 1.14, 95% CI 1.01-1.28) as compared with participants of normal weight. In longitudinal analysis, both weight gain and weight loss were related to the onset of job strain during follow-up. CONCLUSIONS: In an analysis of European data, we found both weight gain and weight loss to be associated with the onset of job strain, consistent with a 'U'-shaped cross-sectional association between job strain and BMI. These associations were relatively modest; therefore, it is unlikely that intervention to reduce job strain would be effective in combating obesity at a population level.

Can strenuous leisure time physical activity prevent psychological complaints in a working population?

AIMS: To investigate the longitudinal relation between strenuous leisure time physical activity and psychological complaints (depression and emotional exhaustion) in a Dutch working population in order to find evidence for the preventive role of physical activity in the development of psychological complaints. METHODS: All data came from the Study on Musculoskeletal disorders, Absenteeism, Stress, and Health (SMASH), a three year follow up study that started between 1994 and 1995. The study population consisted of 1747 workers from 34 companies. Generalised estimating equation (GEE) analyses were performed to investigate the longitudinal relation between strenuous leisure time physical activity and psychological complaints using models with and without a time lag. Logistic regression analyses were performed to study the relation between physical activity and sickness absence due to psychological complaints during the three year follow up study. RESULTS: Only in workers with a sedentary job was strenuous leisure time physical activity (1-2 times per week) significantly associated with a reduced risk of future depression and emotional exhaustion. This was not the case for physical activity at higher frequencies (> or =3 times per week). There was a dose-response relation between strenuous leisure time physical activity and poor general health which was strongest in workers with a sedentary job. Strenuous leisure time physical activity (1-2 times per week) was associated with a lower risk of long term absenteeism (>21 days), whereas physical activity at a higher frequency was not. CONCLUSIONS: Results suggest that strenuous leisure time physical activity might play a role in the prevention of future psychological complaints, poor general health, and long term absenteeism in a working population. Workers with a sedentary job seem to benefit more from strenuous leisure time physical activity than workers without a sedentary job.

High quantitative job demands and low coworker support as risk factors for neck pain: results of a prospective cohort study.

STUDY DESIGN: A 3-year prospective cohort study among 1334 workers was conducted. OBJECTIVE: To determine whether the work-related psychosocial factors of quantitative job demands, conflicting job demands, skill discretion, decision authority, supervisor support, coworker support, and job security are risk factors for neck pain. SUMMARY OF BACKGROUND DATA: Among the various risk factors for neck pain, work-related psychosocial factors play a major role. Previous studies on risk factors for neck pain often had a cross-sectional design, and did not take both physical and psychosocial factors into account. METHODS: At baseline, data on work-related psychosocial factors were collected by means of a questionnaire. During the 3-year follow-up period, data on the occurrence of neck pain were collected by means of postal questionnaires. Individuals without neck pain at baseline were selected for the analyses. Cox regression analysis was applied to examine the relation between the work-related psychosocial factors and the cumulative incidence of neck pain. Adjustments were made for various physical factors and individual characteristics. RESULTS: The analysis included 977 patients. Altogether, 141 workers (14.4%) reported that they had experienced neck pain at least once during the 3-year follow-up period. The relation of neck pain to high quantitative job demands (relative risk [RR], 2.14; 95% confidence interval [CI], 1.28-3.58) and low coworker support (RR, 2.43; 95% CI, 1.11-5.29) was statistically significant. An increased risk was found for low decision authority in relation to neck pain (RR, 1.60; 95% CI, 0.74-3.45), but this relation was not statistically significant. CONCLUSIONS: High quantitative job demands and low coworker support are independent risk factors for neck pain. There are indications that another risk factor for neck pain is low decision authority.

Psychosocial work characteristics and psychological strain in relation to low-back pain.

OBJECTIVES: This study investigated the relationship between psychosocial work characteristics and low-back pain and the potential intermediate role of psychological strain variables in this relationship. METHODS: The research was part of a prospective cohort study of risk factors for musculoskeletal symptoms. The study population consisted of 861 workers from 34 companies in The Netherlands who had no low-back pain at baseline and for whom data on the occurrence of low-back pain were obtained with annual questionnaires during a 3-year follow-up period. Information on psychosocial work characteristics and psychological strain variables was collected using a questionnaire at baseline. Cases of low-back pain were defined as workers who reported, in at least one of the annual follow-up questionnaires, that they had had regular or prolonged low-back pain in the previous 12 months. RESULTS: After adjustment for individual factors and quantified physical load at work, nonsignificant relative risks ranging from 1.3 to 1.6 were observed for high quantitative job demands, high conflicting demands, low supervisory support, and low co-worker support. Decision authority and skill discretion showed no relationship with low-back pain. In general, the estimated relative risks for the psychosocial work characteristics were scarcely influenced by additional adjustment for job satisfaction, emotional exhaustion, and sleeping difficulties. CONCLUSIONS: It can be concluded that low social support, from either supervisors or co-workers, appears to be a risk factor for low-back pain. Some indications of a relationship between high quantitative job demands and high conflicting demands and low-back pain were also found. Little evidence was found for an intermediate role for the psychological strain variables under study.

Job strain and risk indicators for cardiovascular disease in young female nurses.

This study examined the possible effects of job demands, decision latitude, and job-related social support on risk indicators for cardiovascular disease (CVD) in 165 female nurses. Job strain was measured with the Job Content Questionnaire; CVD risk was measured with insulin, total cholesterol, triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), fibrinogen, tissue-type plasminogen activator (tPA) antigen, tPA activity, plasminogen activator inhibitor-1 antigen, and blood pressure. Multivariate analysis of covariance and regression analyses revealed no effects of either job strain or social support on these risk indicators. All risk indicators deteriorated with age and body mass index. Oral contraceptive use improved fibrinolytic potential and increased HDL-C but had adverse effects on TG levels. Results suggest that in healthy young women job strain is not associated with an unfavorable metabolic or fibrinolytic risk profile.

Linear and nonlinear relations between psychosocial job characteristics, subjective outcomes, and sickness absence: baseline results from SMASH. Study on Musculoskeletal Disorders, Absenteeism, Stress, and Health.

This study investigates the demand-control-support (DCS) model by (a) using a more focused measure of job control, (b) testing for interactive and nonlinear relationships, and (c) further extending the model to the prediction of an objective outcome measure (i.e., company-administrated sickness absence). Hypotheses were tested in a heterogeneous sample of 1,739 employees from a 3-year prospective cohort study called SMASH (Study on Musculoskeletal Disorders, Absenteeism, Stress, and Health). Baseline results showed that a linear additive model was superior for job satisfaction, psychosomatic health complaints, and sickness absence, whereas a curvilinear model was superior for emotional exhaustion and depression. It is concluded that, first, there was no evidence of interactive effects. Second, it seems sensible to pay more attention to curvilinear relationships in future research. Finally, the DCS model was not supported using a more objective outcome measure.

Dutch monitor on stress and physical load: risk factors, consequences, and preventive action.

OBJECTIVES: Due to recent changes in legislation on occupational health and safety, a national monitor on stress and physical load was developed in The Netherlands to monitor (a) risks and consequences of stress and physical load at work, (b) preventive actions in companies to reduce these risks, and (c) organisational and environmental variables that facilitate preventive actions. METHODS: Information was gathered from employers, employees, and employees' representatives. The monitor was used with a nationally representative sample of companies in industry, wholesale trade, and banking and finance, 782 companies in total. RESULTS AND CONCLUSIONS: The information from the employees, aggregated at the company level, was not found to be correlated with that from the employer from the same companies. Although many employers do recognise risk factors for both physical load and stress as a problem they often seem to underestimate the problem when compared with employees or their representatives. This is particularly the case for psychosocial risk factors. Also, the perception of outcome measures, especially employers who consider emotional exhaustion to be work related, were fewer than the employees' representatives of the same organisation. Preventive measures on physical load are much more popular than measures against stress. It is the responsibility of the employer to take more preventive action of all kinds. They need to recognise risk factors as problems and health outcomes to be related to work. Employees of larger companies should participate with employers to consider effective measures, and more use should be made of support at branch level. For specific preventive measures, specific predictors emerged. Except for measures to prevent work stress, information from employees did not sufficiently contribute to the initiation of preventive measures in the workplace.

Priorities in occupational health research: a Delphi study in The Netherlands.

OBJECTIVES: To achieve a coherent programme of topics for research in occupational health and safety, with well founded priorities and to relate them to perceived gaps and needs in The Netherlands. METHODS: In the first phase of the study 33 key informants were interviewed. In the second phase questionnaires were sent to 150 Dutch experts (including the key informants). Four groups were recruited, originating from: occupational health and safety services; scientific research institutes; governmental and other administrative bodies; and companies. Using the Delphi technique, the experts were asked to prioritize several topics, which were placed under different headings. In the third phase five workshops were organised to elaborate on the highly prioritized topics. RESULTS: The response rates were 86% for the first and 81% for the second questionnaire. In the second round consistency was reached and consensus proved to be satisfactory; so that the Delphi process was stopped. There were surprisingly few differences in opinion between the four groups. The most important heading was "design/implementation/evaluation of measures", in which the topic cost-benefit analysis of measures had the highest score. "Assessment of relations between exposure and effect" was the second most important heading. Under this heading, topics on work stress were generally judged to be more important than topics on safety and biological, chemical, and physical hazards. The headings "occupational rehabilitation/sociomedical guidance" and "occupational health care/occupational health services" had about the sam priority, closely following the heading "assessment of relations between exposure and effect". CONCLUSIONS: The general agreement on priorities should provide a sufficiently broad basis for decision makers to initiate a long term programme for occupational health research and development in The Netherlands.

Psychosocial stressors at work and musculoskeletal problems.

OBJECTIVES: This paper examines the relationship between work stressors and the following health indicators: psychosomatic complaints, health behavior, and musculoskeletal problems. METHODS: Secondary analyses were performed on data from the National Work and Living Condition Survey, which provides a representative sample of the working population in The Netherlands. The survey was made in 1977, 1983, and 1986 by The Netherlands Central Bureau of Statistics. By means of factor analysis the following three risk dimensions were identified in the survey: work pace, intellectual discretion, and physical stressors. RESULTS: High work pace, low intellectual discretion, and physical stressors were associated with increased health complaints (both psychosomatic and musculoskeletal) and musculoskeletal disorders after adjustment for gender, age, education, and sports participation. Low intellectual discretion, but not high work pace, was associated with poor general health and health behavior indicative of poor health. Physical stressors were associated with general health as well, but not with health behavior, except for reported absenteeism. CONCLUSIONS: Psychosocial stressors are not only associated with psychosomatic complaints and health indicators, but also with musculoskeletal problems, both acute and chronic. Especially the relation between intellectual discretion and musculoskeletal problems can be partly attributed to physical load. Even after adjustment for physical stressors and moderating personal characteristics, the relationships between the psychosocial stressors and musculoskeletal problems remained significant and comparable in strength to the relationship between psychosocial stressors and several other health outcomes, such as psychosomatic complaints.

Stress and coping in lecturing, and the stability of responses across practice.

The central issues of the present paper are the responses to the stress of lecturing in a standardized situation, and the adaptation to this stressor across a period of real-life lecturing practice. Special attention is given to the stability of rank-order in the physiological and psychological responses to the lecturing stressor across practice. Lecturing in the standardized situation involved lecturing at the training institute to six fellow student teachers and two members of the university staff. The responses to be measured were heart rate, cortisol excretion and subjective anxiety. The results indicate that lecturing is stressful for student teachers. The adaptation in stress responses was very significant. Despite the significant reduction in the stress responses, a considerable stability of rank-order was found, indicating that subjects who were the most reactive before practice were still more reactive after practice. The implications of a high stability in reactivity are discussed.

Individual differences in reactivity to and coping with the stress of lecturing.

The aim of this study was to evaluate the moderating effect of several psychologically and biologically defined characteristics for both psychological and physiological indices of reactivity to and coping with lecturing stress. Student teachers were measured in two standardized lecturing situations: once at the start of a three-month practice period and once at the end of this period. Reactivity was operationalized as an increase in heart rate, cortisol excretion and subjective anxiety responses in anticipation of and at the start of the lecture. Coping was operationalized as the attunement of these responses during, or recovery after lecturing (short term coping), and as the adaptation of these responses across the three-month practice period (long term coping). It was found that reactivity to and (particularly long term) coping with the lecturing stressor could well be predicted by moderators such as physical fitness, extraversion, neuroticism, social anxiety and several coping styles. Specificity of predictor sets for sex and response parameters is discussed.

The anxiety thermometer: a validation study.

The aim of our study was to provide validation and reproducible data for the anxiety thermometer. This thermometer is either a continuous or a 10-point Likert-type scale on which subjects are asked to rate their anxiety feelings at a particular moment. It is a quick way to measure state-anxiety. As a validation criterion the State-Trait Anxiety Inventory (STAI) A-State scale was used. To test the reproducibility of the thermometer, a test-retest correlation coefficient was calculated, with a retrospective second thermometer score. The ego-threatening situation used was a written examination. Two experiments were carried out during different examination conditions. The data consistently indicated that the validity and reproducibility of the anxiety thermometer is fair (correlation coefficients between .60 and .78) In the second study, the possible influence of two factors on the retrospective scores were additionally tested.

Comparison of physiology and biomechanics of speed skating with cycling and with skateboard exercise.

Eight well-trained speed skaters performed three all-out tests during ice speed skating, board skating and cycling. Compared to speed skating, cycling produced significantly higher values of oxygen consumption (57.2 +/- 4.9 vs. 53.9 +/- 4.2 ml/(kg X min], ventilation (111.3 +/- 10.2 vs. 98.8 +/- 7.3 l/min) and respiratory exchange ratio (1.18 +/- 0.13 vs. 1.03 +/- 0.05). This seems to suggest a different demand on the aerobic metabolism during cycling compared to speed skating. Board skating resulted in a significantly higher value of the ventilation (110.0 +/- 8.6 l/min) only. Kinematic analysis showed that during both skating activities the time series of the hip and knee angles, angular velocities and angular accelerations were similar. High peak values, especially of the knee angular acceleration, occur in the short push-off phase. During cycling completely different curves were found. The possible significance of these differences for movement co-ordination and motor unit involvement is discussed. The results show that board skating is a more specific training exercise for speed skating than cycling, at least when training for skating performances lasting 8-10 minutes at most.

Stress in student teachers during real and simulated standardized lectures.

This study describes and compares the intensity of stress responses, both psychologically and physiologically, to a real and a simulated stressor. The real stressor involved lecturing to a class of students in a post-secondary institution during a practice teaching course. The simulated stressor was a simulated, standardized lecture given in a lecture room to 6 fellow students and 2 members of the university staff. To gain insight into the intensity of the stress responses, the measurements took place before, during, and after lecturing. The adaptation to the stressor after a teaching practice period in which the student teacher gave at least 20 lectures was also studied. Subjective anxiety scores were obtained in both situations from 26 subjects. For 12 of these subjects, heart rate responses were also obtained. The psychological and physiological data indicated that lecturing imposes a severe load on the student teacher, especially at the beginning of the teaching experience. At the end of the practice course, all stress indices showed lower values. Heart rate and subjective anxiety scores indicated that the standardized lecture is experienced as more ego threatening than the real lecture.