Sven-Olof Isacsson

Incidence of shoulder and neck pain in a working population: effect modification between mechanical and psychosocial exposures at work? Results from a one year follow up of the Malmö shoulder and neck study cohort

Study objective: To assess the impact of mechanical exposure and work related psychosocial factors on shoulder and neck pain. Design: A prospective cohort study. Participants: 4919 randomly chosen, vocationally active men and women ages 45–65 residing in a Swedish city. Neck and shoulder pain were determined by the standardised Nordic questionnaire. Mechanical exposure was assessed by an index based on 11 items designed and evaluated for shoulder and neck disorders. Work related psychosocial factors were measured by the Karasek and Theorell demand-control instrument. Main results: High mechanical exposure was associated with heightened risk for shoulder and neck pain among men and women during follow up. Age adjusted odds ratios (OR) were 2.17 (95% confidence intervals (CI): 1.65, 2.85) and 1.59 (95% CI: 1.22, 2.06), respectively. In women, job strain (high psychological job demands and low job decision latitude) correlated with heightened risk (OR = 1.73, 95% CI: 1.29, 2.31). These risk estimates remained statistically significant when controlled for high mechanical exposure regarding job strain (and vice versa), and for sociodemographic factors. Testing for effect modification between high mechanical exposure and job strain showed them acting synergistically only in women. Conclusion: Job related mechanical exposure in both sexes, and psychosocial factors in women, seem independently of each other to play a part for development of shoulder and neck pain in vocationally active people. The effect of psychosocial factors was more prominent in women, which could be the result of biological factors as well as gender issues. These results suggest that interventions aiming at reducing the occurrence of shoulder and neck pain should include both mechanical and psychosocial factors.

Reliability and validity assessments of measures of social networks, social support and control — results from the Malmö Shoulder and Neck Study

The reliability and validity of methods to assess social networks, social support and control were investigated in a population of 12,009 females and males born between 1926 and 1945 (the “Malmö Shoulder and Neck Study”). This study demonstrated an overall reliability with kappa coefficients between 0.70 and 0.47, but the reliability was more varying among females and lower in the youngest age group. The analysis of the construct validity indicated that the different indices measure different aspects of the psychosocial environment, but both theoretical and methodological problems were identified, when the validity of multidimensional concepts are to be determined. The validity of such indices can best be judged by combining quantitative and qualitative methods. Potential validity problems must be kept in mind when these indices are used in epidemiological research. The results from the reliability analysis call for repeated assessments and the sample size must be adjusted vis-à-vis the reliability.

Ten year cerebrovascular morbidity and mortality in 68 year old men with asymptomatic carotid stenosis

Abstract Objective: To study the natural course of carotid artery stenosis detected by ultrasonography. Design: Prospective cohort study. Baseline examination in 1982-3 included ultrasound examination of carotid arteries, measurement of anklebrachial blood pressure index, and detection of atrial fibrillation by 24 hour ambulatory electrocardiography. Setting: Malmo, a city in southern Sweden with 230000 inhabitants. Subjects: 470 men aged 68 years randomly selected from the population. Main outcome measures: Incidence of stroke and transient ischaemic attack and all cause mortality during 10 years of follow up in relation to carotid stenosis, leg artery disease (ankle-brachial blood pressure index below 0.9), and atrial fibrillation. Results: Fifty men had a stroke; six of these were haemorrhagic. Another 11 had a transient ischaemic attack. Eighteen of the men with carotid stenosis (21.6 events/1000 person years) and 43 of the men with normal carotid arteries (14.8 events/1000 person years) had a stroke or transient ischaemic attack (P=0.188). Men with atrial fibrillation had an increased rate of cerebrovascular events (36.7/1000 person years (P=0.048). The highest rate was found in men with asymptomatic disease of the leg arteries (38.6/1000 person years) (P<0.001). The increased risk of stroke or transient ischaemic attack in this group remained after multivariate analysis (relative risk 2.0; 95% confidence interval 1.1 to 3.7). Conclusions: In this cohort carotid stenosis was not associated with an increased risk of stroke. Part of this lack of association was explained by the high mortality from ischaemic heart disease in men with severe stenosis. Twenty seven of the 61 cerebrovascular events, however, occurred in men who had normal carotid arteries, normal ankle pressure, and no atrial fibrillation. Key messages Key messages Asymptomatic atherosclerosis in carotid and leg arteries is a common occurrence among elderly people Both conditions were found to be associated with an excess cardiovascular mortality Compared with leg artery disease, asymptomatic carotid stenosis was not found to be associated with an increased risk of stroke Assessment of peripheral atherosclerotic disease by measurement of arm and ankle blood pressure is a useful method for identifying patients with an increased risk of stroke

The experience of pain from the shoulder-neck area related to the total body pain, self-experienced health and mental distress

The present paper presents the relationship between the total body-pain (TBP) score, defined as the total number of areas shaded on a pain drawing, and the pain from one area, the Shoulder-Neck (SN), among subjects in or out of full-time gainful work respectively. Furthermore, relationships between pain-score, self-experienced health (SEH) and level of mental distress, measured with the General Health Questionnaire (GHQ) were investigated. The analyses is based on a general population sample of 8,116 men and women, 45-60 years of age, completing a questionnaire in the Malmö Shoulder Neck Study. The TBP-score was higher with increasing pain from the SN area, being out of full-time work and among women. Independently of working status, the SEH decreased with increasing pain in the SN area, which was enhanced, by increasing TBP-score. The proportion of women out of full-time gainful work was twice as high as for men. Women showed the same SEH levels with regard to their pain status, independently of their working status while men working full-time scored higher than women did. Oppositely, men out of full-time work had the lowest SEH in relation to their pain status. The GHQ scores of mental distress varied essentially in the same way as the SEH did. The results emphasize the need for an assessment of the number of pain locations and which one that first gave symptoms when studying possible causal relationships between low force musculoskeletal load and development of localized pain. If such data are not collected in epidemiological studies on causes for musculoskeletal pain it will at best lead to unnoticed effect modifications. At worst a potential confounding situation may occur. The relationship between the self-experienced health, mental distress and chronic pain identifies chronic pain as a major public-health problem and suggests a multidisciplinary approach in the treatment and rehabilitation already before work capacity is lost.

Long term and transitional intermittent smokers: a longitudinal study

Objective: To investigate differences in snuff consumption, sociodemographic and psychosocial characteristics between baseline intermittent smokers that had become daily smokers, stopped smoking or remained intermittent smokers at the one year follow up. Design/setting/participants/measurements: A population of 12 507 individuals interviewed at baseline in 1992-94 and at a one year follow up, aged 45–69 years, was investigated in a longitudinal study. The three groups of baseline intermittent smokers were compared to the reference population (all others) according to sociodemographic, psychosocial, and snuff consumption characteristics. A multivariate logistic regression model was used to assess differences in psychosocial conditions, adjusting for age, sex, country of origin, marital status, education, and snuff consumption. Results: 60% of all baseline intermittent smokers had remained intermittent smokers, 16% had become daily smokers, and 24% had stopped smoking at the one year follow up. The long term intermittent smokers and those who had stopped smoking were young, unmarried, highly educated, and snuff consumers to a higher extent than the reference population. They also had more psychosocial resources than the reference population, while the psychosocial resources of those who had become daily smokers were poorer. Conclusions: The majority of intermittent smokers are long term intermittent smokers. The results suggest that long term intermittent smokers have other psychosocial characteristics than daily smokers.

Impact of different aspects of social participation and social capital on smoking cessation among daily smokers: a longitudinal study

Objective: To investigate differences in different aspects of social participation and social capital among baseline daily smokers that had remained daily smokers, become intermittent smokers, or stopped smoking at one year follow up. Design/setting/participants/measurements: 12 507 individuals, aged 45–69 years, interviewed at baseline between 1992 and 1994 and at a one year follow up were investigated in this longitudinal study. The three groups of baseline daily smokers were compared to the reference population (baseline intermittent smokers and non-smokers) according to different aspects of social participation and social capital. A multivariate logistic regression model was used to assess differences in different aspects of social participation and social capital. Results: The baseline daily smokers that remained daily smokers at the one year follow up had significantly increased odds ratios of non-participation in study circles in other places than at work, meeting of organisations other than unions, theatre/cinema, arts exhibition, church, sports events, large gatherings of relatives, and private parties compared to the reference population. The baseline daily smokers that had become intermittent smokers at the one year follow up had significantly increased odds ratios of non-participation in church services. The baseline daily smokers that had stopped smoking had increased odds ratios of non-participation in having attended a meeting of organisations other than labour unions during the past year, having been to a theatre or cinema, and of having visited an arts exhibition during the past year. All three categories of baseline daily smokers had significantly decreased odds ratios of non-participation in night club/entertainment. Conclusions: The baseline daily smokers that had remained daily smokers at the one year follow up had particularly high rates of non-participation compared to the reference population in both activities specifically related to social capital, such as other study circles, meetings of organisations other than labour unions, and church attendance and cultural activities such as theatre/cinema and arts exhibition, although significantly lower participation in cultural activities and meetings of other organisations was also observed among daily smokers that had stopped smoking. All three baseline daily smoker groups had higher rates of having visited a night club during the past year.

Job stress and major coronary events: results from the Job Stress, Absenteeism and Coronary Heart Disease in Europe study.

Aims The intention of this study is to investigate the relationship of the demands/control/strain model with hard coronary events in an epidemiological, prospective, multicenter, European study. Methods and results Six cohorts (Brussels, Ghent, Lille, Barcelona, Göteborg and Malmö) from four European countries (Belgium, France, Spain and Sweden) consisting of 21 111 middle-aged male subjects participated between 1993 and 1996 in the baseline survey of the Job Stress, Absenteeism and Coronary Heart Disease in Europe (JACE) study. The Karasek strain model of psychological demands (five items)/control (nine items) was used. During a mean follow-up of 40 months 185 acute coronary events or coronary deaths were observed. Age-adjusted hazard ratios (HRs) for developing an acute coronary event were 1.46 [CI 95% confidence interval (1.08–1.97)] for high against low psychological demands and 1.53 (95% CI 1.0–2.35) for strained (high demands plus low control) against relaxed (low demands plus high control) groups. After adjustment for standard cardiovascular risk factors the HR for developing a coronary event for those above or equal to the median against those below the median of psychological demands was 1.46 (95% CI 1.08–1.97) whereas the HR for strained against relaxed groups is 1.46 (95% CI 0.96–2.25). Sensitivity analyses confirmed the robustness of the results. Conclusion In this European, multicenter, prospective, epidemiological study the Karasek job strain model was an independent predictor of acute coronary events, with the psychological demands scale emerging as the important component.

Incidence of myocardial infarction in elderly men being treated with antihypertensive drugs: population based cohort study.

Abstract Objective: To analyse the association between use of antihypertensive treatment, diastolic blood pressure, and long term incidence of ischaemic cardiac events in elderly men. Design: Population based cohort study. Baseline examination in 1982-3 and follow up for up to 10 years. Setting: Malmo, Sweden. Subjects: 484 randomly selected men born in 1914 and living in Malmo during 1982. Main outcome measures: Observational comparisons of incidence rates and rate and hazard ratios of ischaemic cardiac events (myocardial infarction or death due to chronic ischaemic cardiac disease). Results: The crude incidence rate of ischaemic cardiac events was higher in those subjects who were taking antihypertensive drugs than in those who were not (rate ratio 2.6 (95% confidence interval 1.7 to 3.9)). After adjustment for potential confounders (differences in baseline smoking habits, blood pressure, time since diagnosis of hypertension, ischaemic or other cardiovascular disease, hypercholesterolaemia, hypertriglyceridaemia, diabetes mellitus, obesity, and raised serum creatinine concentration) this rate was reduced but still raised (hazard ratio 1.9 (1.0 to 3.7)). In men with diastolic blood pressure >90 mm Hg, antihypertensive treatment was associated with a twofold increase in the incidence of ischaemic cardiac events (rate ratio 2.0 (1.1 to 3.6)), which vanished after adjustment for potential confounders (hazard ratio 1.1 (0.5 to 2.6)). In those subjects with diastolic blood pressure </=90 mm Hg, antihypertensive treatment was associated with fourfold increase in incidence (rate ratio 3.9 (2.1 to 7.1)), which remained after adjustment for potential confounders (hazard ratio 3.8 (1.3 to 11.0)). Conclusion: Antihypertensive treatment may increase the risk of myocardial infarction in elderly men with treated diastolic blood pressures </=90 mm Hg.

Control of blood pressure and risk of first acute myocardial infarction: Skaraborg hypertension project

Abstract Objective: To analyse the relation between treated blood pressure and concomitant risk factor and morbidity from acute myocardial infarction. Design: Prospective longitudinal study. Treated blood pressures and other variables were used to predict acute myocardial infarction. Setting: Primary health care in Skaraborg, Sweden. Subjects: 1121 men and 1453 women aged 40-69 years at registration at outpatient clinics, 1977-81, with no evidence of previous myocardial infarction were followed up for an average of 7.4 years. Subjects were undergoing treatment with drugs to lower blood pressure or had blood pressure that exceeded the systolic or diastolic limits, or both, for diagnosis (>170/>105 mm Hg (patients aged 40-60 years) and >180/>110 mm Hg (older than 60 years)) on three different occasions, or both. Main outcome measures: First validated event of fatal or non-fatal acute myocardial infarction. Results - In men but not in women there was a negative relation between treated diastolic blood pressure and risk of acute myocardial infarction. Left ventricular hypertrophy and smoking were contributory risk factors in both sexes, as was serum cholesterol concentration in men. In men with normal electrocardiograms (n=345) risk increased with increasing diastolic blood pressure (P=0.047), whereas the opposite was found in men with electrocardiograms suggesting ischaemia or hypertrophy, or both (n=499, P=0.009). In those with a reading of 95-99 mm Hg the relative risk was 0.30 (P=0.034); at >=100 mm Hg it was 0.37 (P=0.027). No similar relations were seen in women or for systolic blood pressure. Conclusion: It may be hazardous to lower diastolic20blood pressure below 95 mm Hg in hypertensive men with possible ischaemia or hypertrophy, or both. Electrocardiographic findings should be considered when treatment goals are decided for men with hypertension.

Sleeping problems as a risk factor for subsequent musculoskeletal pain and the role of job strain: Results from a one-year follow-up of the Malmö shoulder neck study cohort

Background: The role of sleeping problems in the causal pathway between job strain and musculoskeletal pain is not clear.Purpose: To investigate the impact of sleeping problems and job strain on the one-year risk for neck, shoulder, and lumbar pain.Method: A prospective study, using self-administered questionnaires, of a healthy cohort of 4,140 vocationally active persons ages 45–64, residing in the city of Malmö.Results: At follow-up, 11.8% of the men and 14.8% of the women had developed pain. The odds ratios (OR) for pain at follow-up and sleeping problems at baseline were 1.72 (95% CI: 1.13–2.61) in men and 1.91 (1.35–2.70) in women. Regarding exposure to job strain, ORs were 1.39 (0.94–2.05) for men and 1.63 (1.18–2.23) for women. These statistically significant risks remained so when controlled for possible confounding. A modest synergistic effect was noted in women with concurrent sleeping problems and job strain, but not in men.Conclusion: One in 15–20 of all new cases of chronic pain in the population could be attributed to sleeping problems. No evidence was found for a causal chain with job strain leading to musculoskeletal pain by the pathway of sleeping problems.