The effect of leisure-time physical activity on the risk of acute myocardial infarction depending on Body Mass Index: a population-based case-control study

BACKGROUND: High body mass index (BMI) and lack of physical activity have been recognized as important risk factors for coronary heart disease. The aim of the present study was to evaluate whether leisure-time physical activity compensates for the increased risk of acute myocardial infarction associated with overweight and obesity. METHODS: Data from the SHEEP (Stockholm Heart Epidemiology Program) study were used. The SHEEP study is a large Swedish population-based case-control study, comprising 1204 male and 550 female cases, and 1538 male and 777 female controls, conducted in Stockholm County, Sweden, during the period 1992–1994. Odds ratios (OR), together with 95 % confidence intervals (95% CI), were calculated using unconditional logistic regression, as estimates of the relative risks. RESULTS: Regular leisure-time physical activity was associated with a decreased risk of myocardial infarction among lean, normal-weight and overweight subjects, but not among obese subjects. Obese (BMI ≥ 30) and physically active persons had an almost twofold risk of myocardial infarction, compared with normal-weight and sedentary persons (OR 1.85, 95% CI 1.07–3.18). The results were similar for men and women. CONCLUSION: While regular leisure-time physical activity seems to provide protection against myocardial infarction among lean, normal-weight and overweight subjects, this does not appear to be the case in obese subjects

A comparison of occupational and non-occupational exposure to diesel exhausts and its consequences for studying health effects

published on September 21, 2012 as 10.1136/oemed-2012-101134</p

Mortality attributable to occupational exposure in Sweden

OBJECTIVES: The objective of this study was to estimate the mortality from cancer, cardiovascular, and respiratory diseases attributable to occupational exposure in Sweden. METHODS: Estimates were calculated for men and women separately, and we considered only deaths between 25-74 years of age. We considered cancer exposures/sites classified as I or 2a according to the International Agency for Research on Cancer (IARC). Acute myocardial infarction was the only included cardiovascular disease. Respiratory diseases comprised chronic obstructive pulmonary disease (COPD) asthma, pneumoconiosis and alveolitis. All deaths of pneumoconiosis and alveolitis were considered work-related. Estimates were based on the Swedish mortality in 2007. RESULTS: In total, we estimate that there are about 800 work-related deaths per year in the studied causes. The majority are due to acute myocardial infarction, with 126 deaths among women and 337 deaths among men attributable to job strain, shift work, exhaust gases, combustion products, or environmental tobacco smoke (ETS). There are 99 respiratory disease-related deaths, the vast majority from COPD (N=92). In total, 270 cancer deaths are estimated to be work-related. For men, half of the cases are attributed to asbestos exposure. CONCLUSIONS: Our results indicate that preventive measures to decrease occupational mortality should consider factors associated with myocardial infarction such as job strain, shift work and exhaust gases from vehicles and combustion products. Exposures to factors associated with COPD, such as dust, also seem important to prevent

Work situation and self-perceived economic situation as predictors of change in burnout - a prospective general population-based cohort study

Background: Sick leave rates due to mental and behavioural disorders have increased in Sweden during the last decades. The aim of this prospective study was to investigate changes in the level of burnout in a working subset of the general population and to identify how such changes relate to changes in work situation and self-perceived economic situation. Methods: A cohort of 1000 persons from a subset of the 2004 northern Sweden MONICA (Multinational Monitoring of Trends and Determinants in Cardiovascular Disease) general population survey was followed over a five-year period (2004-2009). In total, 623 persons (323 women and 300 men) were included in the analysis. Burnout levels were measured at baseline and follow-up using the Shirom Melamed Burnout Questionnaire. Risk factors were assessed at both measuring points. Results: In the whole study cohort, a small (-0.15) but statistically significant reduction in burnout level was found. No differences in change of burnout were found between men and women. Constant strain at work, an increased risk of unemployment, and a perceived worsening of economic situation during the study time period were related to an increased burnout level. An accumulation of these risk factors was associated with increased burnout level. Conclusions: Risk factors in work situation and self-perceived economy are related to changes in burnout level, and special attention should be directed towards persons exposed to multiple risk factors

Is the effect of job strain on myocardial infarction risk due to interaction between high psychological demands and low decision latitude? Results from Stockholm Heart Epidemiology Program (SHEEP)

The objectives are to examine if the excess risk of myocardial infarction from exposure to job strain is due to interaction between high demands and low control and to analyse what role such an interaction has regarding socioeconomic differences in risk of myocardial infarction. The material is a population-based case-referent study having incident first events of myocardial infarction as outcome (SHEEP: Stockholm Heart Epidemiology Program). The analysis is restricted to males 45-64 yr of age with a more detailed analysis confined to those still working at inclusion. In total, 1047 cases and 1450 referents were included in the analysis. Exposure categories of job strain were formed from self reported questionnaire information. The results show that high demands and low decision latitude interact with a synergy index of 7.5 (95% C.I.: 1.8-30.6) providing empirical support for the core mechanism of the job strain model. Manual workers are more susceptible when exposed to job strain and its components and this increased susceptibility explains about 25-50% of the relative excess risk among manual workers. Low decision latitude may also, as a causal link, explain about 30% of the socioeconomic difference in risk of myocardial infarction. The distinction between the interaction and the causal link mechanisms identifies new etiologic questions and intervention alternatives. The specific causes of the increased susceptibility among manual workers to job strain and its components seem to be an interesting and important research question.job strain myocardial infarction socioeconomic status susceptibility

Work situation and self-perceived economic situation as predictors of change in burnout - a prospective general population-based cohort study

Background: Sick leave rates due to mental and behavioural disorders have increased in Sweden during the last decades. The aim of this prospective study was to investigate changes in the level of burnout in a working subset of the general population and to identify how such changes relate to changes in work situation and self-perceived economic situation. Methods: A cohort of 1000 persons from a subset of the 2004 northern Sweden MONICA (Multinational Monitoring of Trends and Determinants in Cardiovascular Disease) general population survey was followed over a five-year period (2004-2009). In total, 623 persons (323 women and 300 men) were included in the analysis. Burnout levels were measured at baseline and follow-up using the Shirom Melamed Burnout Questionnaire. Risk factors were assessed at both measuring points. Results: In the whole study cohort, a small (-0.15) but statistically significant reduction in burnout level was found. No differences in change of burnout were found between men and women. Constant strain at work, an increased risk of unemployment, and a perceived worsening of economic situation during the study time period were related to an increased burnout level. An accumulation of these risk factors was associated with increased burnout level. Conclusions: Risk factors in work situation and self-perceived economy are related to changes in burnout level, and special attention should be directed towards persons exposed to multiple risk factors

Interaction between Shift Work and Established Coronary Risk Factors

Background: Shift work is associated with increased risk of cardiovascular disease, but the causes have not yet been fully established. It has been proposed that the coronary risk factors are more hazardous for shift workers, resulting in a potential interaction effect with shift work. Objective: To analyse interaction effects of work schedule and established risk factors for coronary artery disease on the risk of myocardial infarction. Methods: This analysis was conducted in SHEEP/VHEEP, a case-control study conducted in two counties in Sweden, comprising all first-time cases of myocardial infarction among men and women 45-70 years of age with controls stratified by sex, age, and hospital catchment area, totalling to 4648 participants. Synergy index (SI) was used as the main outcome analysis method for interaction analysis. Results: There was an interaction effect between shift work and physical inactivity on the risk of myocardial infarction with SI of 2.05 (95% CI 1.07 to 3.92) for male shift workers. For female shift workers, interaction effects were found with high waist-hip ratio (SI 4.0, 95% CI 1.12 to 14.28) and elevated triglycerides (SI 5.69, 95% CI 1.67 to 19.38). Conclusion: Shift work and some established coronary risk factors have significant interactions