Childhood abuse and unplanned pregnancies: a cross-sectional study of women in the Norwegian Mother and Child Cohort Study.

OBJECTIVE: To study if childhood emotional, physical and sexual abuse are determinants for having an unplanned pregnancy, if the categories of abuse interact, and if a potential bias due to the selection of the participants (collider stratification bias) could explain the effect of childhood abuse. DESIGN: A cross-sectional study. SETTING: The study is based on the Norwegian Mother and Child Cohort Study (MoBa) and uses data from the Medical Birth Registry of Norway. SAMPLE: Women participating in the MoBa for the first time, ≥18 years of age who responded to questions regarding childhood abuse and pregnancy planning (n = 76 197). METHODS: Data were collected using questionnaires. We conducted analyses using modified Poisson regressions and the relative excess risks due to interaction (RERI). Sensitivity analyses were performed. MAIN OUTCOME MEASURE: An unplanned pregnancy (yes/no). RESULTS: Exposure to childhood emotional (adjusted relative risk [RR] 1.14, 95% CI 1.10-1.19), physical (adjusted RR 1.11, 95% CI 1.04-1.18) and sexual (adjusted RR 1.20, 95% CI 1.14-1.27) abuse increased the risk of having an unplanned pregnancy. The effects could not be explained by the collider stratification bias. The different combinations of categories of abuse did not show any interaction effects. CONCLUSIONS: Childhood emotional, physical and sexual abuses separately increase the risk of having an unplanned pregnancy. The results indicate that victims of childhood abuse are in greater need of support to achieve their reproductive goals. TWEETABLE ABSTRACT: Childhood abuse increases the risk of having an unplanned pregnancy. #reproductivehealth #epitwitter.

Shift work, parental cardiovascular disease and myocardial infarction in males.

Background: Shift work has been associated with an increased risk of cardiovascular disease (CVD). However, there is a need for more studies to determine whether there is an interaction between shift work and other risk factors of CVD, thereby increasing the risk of CVD in shift workers. Aims: To discern whether shift work and parental mortality from myocardial infarction (MI) or sudden cardiac death (SCD) interact to increase the risk of MI in men. Methods: A case-control dataset was used to assess interaction between shift work and parental history of CVD, using death from MI or SCD, or death before age 65, on an additive scale. Results were reported as relative excess risk due to interaction, attributable proportion due to interaction (AP) and synergy index (SI). Results: There was an interaction between shift work and paternal mortality from MI or SCD, when both factors were present [SI = 2.39; 95% confidence interval (CI) 1.02‒5.6 and AP = 0.4; 95% CI 0.08‒0.73]. Conclusions: Paternal mortality from MI or SCD interacts with shift work to increase the risk of MI in men.

Snus (Swedish smokeless tobacco) use and risk of stroke: pooled analyses of incidence and survival.

BACKGROUND: Snus is a moist smokeless tobacco product with high nicotine content. Its use has a short-term effect on the cardiovascular system, but the relationship between snus use and stroke is unclear. OBJECTIVE: The aim of this study was to assess the associations between use of snus and incidence of and survival after stroke, both overall and according to subtypes. METHODS: Pooled analyses of eight Swedish prospective cohort studies were conducted, including 130 485 men who never smoked. We estimated hazard ratios (HRs) with 95% confidence intervals (CIs) of incidence and death after diagnosis using Cox proportional hazard regression models and case fatality and survival using logistic regression and Kaplan-Meier methods, respectively. RESULTS: No associations were observed between the use of snus and the risk of overall stroke (HR 1.04, 95% CI 0.92-1.17) or of any of the stroke subtypes. The odds ratio (OR) of 28-day case fatality was 1.42 (95% CI 0.99-2.04) amongst users of snus who had experienced a stroke, and the HR of death during the follow-up period was 1.32 (95% CI 1.08-1.61). CONCLUSION: Use of snus was not associated with the risk of stroke. Hence, nicotine is unlikely to contribute importantly to the pathophysiology of stroke. However, case fatality was increased in snus users, compared with nonusers, but further studies are needed to determine any possible causal mechanisms.

Do physical activity level and body mass index predict recovery from persistent neck pain in men and women of working age? A population-based cohort study.

PURPOSE: The study sought to examine the gender-specific effects of physical activity level and body mass index on recovery from persistent neck pain (PNP) among citizens of working age in Stockholm, Sweden. METHODS: A population-based cohort of 1,730 subjects (18-65) with PNP answered surveys in 2002 and 2007. Prognostic factors were self-reported body mass index (BMI) and physical activity level (PAL) at baseline. Analyses were performed with odds ratios (OR) with corresponding 95 % confidence intervals (95 % CI). RESULTS: Women reporting higher physical activity level had higher odds of recovering from PNP than women with sedentary leisure time (OR of 1.5, 95 % CI 1.0-2.4), but no associations were found in men. No associations were found between BMI and recovery from PNP in any analyses. CONCLUSION: Physical activity seems to be associated with recovery from PNP in women and should therefore be encouraged. Future studies should continue investigating physical activity and lifestyle factors in relation to recovery from persistent neck pain, since these modifiable factors may be considered in interventions.

Job strain predicts recurrent events after a first acute myocardial infarction: the Stockholm Heart Epidemiology Program.

OBJECTIVES: Studies investigating the prognostic role of job stress in coronary heart disease are sparse and have inconclusive findings. We aimed (i) to investigate whether job strain predicts recurrent events after acute myocardial infarction (AMI) and if so (ii) to determine behavioural and biological factors that contribute to the explanation of this association. DESIGN: Prospective study. SETTING: Ten emergency hospitals in the larger Stockholm area, Sweden. SUBJECTS: Non-fatal AMI cases from the Stockholm Heart Epidemiology Program case-control study who were employed and younger than 65 years at the time of their hospitalization (n = 676). RESULTS: During the 8.5 year follow-up, 155 patients experienced cardiac death or non-fatal AMI; totally 96 patients died, 52 of cardiac causes. After adjustment for potential confounders, patients with high job strain had an increased risk for the combination of cardiac death and non-fatal AMI relative to those with low job strain, the hazard ratio (HR) and the 95% confidence interval (CI) being 1.73 (1.06-2.83). Results were similar for cardiac [HR (95% CI): 2.81 (1.16-6.82)] and total mortality [HR (95% CI): 1.65 (0.91-2.98)]. We found no evidence for mediation from lifestyle, sleep, lipids, glucose, inflammatory and coagulation markers on the association between job strain and the combination of cardiac death and non-fatal AMI. CONCLUSIONS: Job strain was associated with poor long-term prognosis after a first myocardial infarction. Interventions focusing on reducing stressors at the workplace or on improving coping with work stress in cardiac patients might improve their survival post-AMI.

Recent time trends in levels of self-reported anxiety, mental health service use and suicidal behaviour in Stockholm.

OBJECTIVE: To investigate recent time trends in several indicators of mental ill-health and the patterning of these indicators between genders and younger vs. older individuals in Stockholm County. METHOD: Several indicators were used; self-reported anxiety from the Swedish Survey of Living Conditions, information on psychiatric in-patient and out-patient care, attempted and completed suicides from national and regional registers. Gender- and age-specific trends were compared for the time period of 1997-2006. RESULTS: Self-reported anxiety and psychiatric service use increased among young individuals of both genders, while attempted suicides increased only among young women. By contrast, these indicators decreased or remained stable in the older age group from year 2001 and onwards. CONCLUSION: Our data indicate a rising, and highly prevalent, mental ill-health among the young in Stockholm County, a region representative of urbanized, secular Western societies.

Prognostic role of the glucometabolic status assessed in a metabolically stable phase after a first acute myocardial infarction: the SHEEP study.

OBJECTIVES: Our objective was to examine fasting glucose and insulin levels in patients surviving 3 months after a first AMI in relation to long-term prognosis. DESIGN: A total of 1167 consecutive patients between 45 and 70 years with a first nonfatal AMI underwent a standardized clinical examination and were followed for a mean of 8 years for total and cardiac mortality and hospitalization for nonfatal cardiovascular disease. Impaired fasting glucose (IFG) was defined as fasting glucose between 5.6 and 7 mmol L(-1) and a level >or=7 mmol L(-1) as newly detected diabetes. Patients with a fasting glucose level <5.6 mmol L(-1) and without a history of diabetes were classified as normoglycemic (NG). An estimate of insulin resistance was calculated using the homeostasis model assessment (HOMA). RESULTS: We recorded 219 deaths, 121 deaths from cardiac causes, during the follow-up period. After adjustment for several potential confounders, hazard ratios for total mortality were 1.36 (95% confidence interval 0.93-1.99, P=0.11), 2.27 (1.26-4.09, P=0.006) and 2.15 (1.43-3.21, P<0.001) for patients with IFG, newly detected diabetes and history of diabetes when compared to the NG group. Cardiac mortality, risk of hospitalization for recurrent nonfatal AMI, stroke or heart failure generally showed a similar pattern to that of total mortality. Insulin level and HOMA values were also associated with increased risk for recurrent events. CONCLUSIONS: We confirmed that both known and newly detected diabetes is a strong prognostic factor in AMI. In addition, our findings suggest that glucose levels below the diabetes cut off value might also predict poor long-term prognosis when assessed in a metabolically stable phase.

Chocolate consumption and mortality following a first acute myocardial infarction: the Stockholm Heart Epidemiology Program.

OBJECTIVES: To assess the long-term effects of chocolate consumption amongst patients with established coronary heart disease. DESIGN: In a population-based inception cohort study, we followed 1169 non-diabetic patients hospitalized with a confirmed first acute myocardial infarction (AMI) between 1992 and 1994 in Stockholm County, Sweden, as part of the Stockholm Heart Epidemiology Program. Participants self-reported usual chocolate consumption over the preceding 12 months with a standardized questionnaire distributed during hospitalization and underwent a health examination 3 months after discharge. Participants were followed for hospitalizations and mortality with national registries for 8 years. RESULTS: Chocolate consumption had a strong inverse association with cardiac mortality. When compared with those never eating chocolate, the multivariable-adjusted hazard ratios were 0.73 (95% confidence interval, 0.41-1.31), 0.56 (0.32-0.99) and 0.34 (0.17-0.70) for those consuming chocolate less than once per month, up to once per week and twice or more per week respectively. Chocolate consumption generally had an inverse but weak association with total mortality and nonfatal outcomes. In contrast, intake of other sweets was not associated with cardiac or total mortality. CONCLUSIONS: Chocolate consumption was associated with lower cardiac mortality in a dose dependent manner in patients free of diabetes surviving their first AMI. Although our findings support increasing evidence that chocolate is a rich source of beneficial bioactive compounds, confirmation of this strong inverse relationship from other observational studies or large-scale, long-term, controlled randomized trials is needed.

Use of snus and risk for cardiovascular disease: results from the Swedish Twin Registry.

OBJECTIVE: To study the association between snus use and the risk for cardiovascular disease, i.e. ischemic heart disease and stroke. DESIGN: Cohort study. SETTING: Sweden. SUBJECTS: Sixteen thousand six hundred and forty-two male Swedish twins participating in the Screening Across the Lifespan Twin Study, conducted in 1998- 2002, were followed for incident cardiovascular disease. Participants were without a history of cardiovascular disease at baseline and incident cases were identified via the Swedish Cause of Death Register and Hospital Discharge Register. RESULTS: Overall, there was no association between use of snus and risk for cardiovascular disease. Current snus users, without a smoking history, had a relative risk of 1.00 (95% confidence interval 0.69-1.46) for cardiovascular disease as compared to non users. Corresponding relative risks for ischemic heart disease and stroke were 0.85 (95% confidence interval 0.51-1.41) and 1.18 (95% confidence interval 0.67-2.08), respectively. In smoking adjusted models, risk estimates for ischemic heart disease in relation to snus use were all close to unity regardless of timing or intensity of snus use. However, current heavy snus users (consuming more than four cans week(-1)) had a relative risk for stroke of 1.75 (95% confidence interval 0.95-3.21). CONCLUSION: These data do not support any strong association between snus use and risk for cardiovascular disease.

Socio-economic position at three points in life in association with type 2 diabetes and impaired glucose tolerance in middle-aged Swedish men and women.

BACKGROUND: It has been suggested that low socio-economic position (SEP) during childhood and adolescence predicts risk of adult type 2 diabetes. We investigated the associations between type 2 diabetes and childhood SEP (fathers' occupational position), participants' education and adult SEP (participants' occupational position). To determine possible independent associations between early SEP (fathers' occupational position and participants' education) and disease, we adjusted for adult SEP and factors present in adult life associated with type 2 diabetes. METHODS: This cross-sectional study comprised 3128 men and 4821 women aged 35-56 years. All subjects have gone through a health examination and answered a questionnaire on lifestyle factors. At the health centre, an oral glucose tolerance test was administered and identified 55 men and 52 women with previously undiagnosed type 2 diabetes. Relative risks (RRs) with 95% CIs were calculated in multiple logistic regression analyses. RESULTS: The age-adjusted RRs of type 2 diabetes if having a father with middle occupational position were 2.3 [Confidence interval (CI:1.0-5.1) for women and, 2.0 (CI:0.7-5.6) for men]. Moreover, low education was associated with type 2 diabetes in women, RR = 2.5 (CI:1.2-4.9). Low occupational position in adulthood was associated with type 2 diabetes in women, RR = 2.7 (CI:1.3-5.9) and men, RR = 2.9 (CI:1.5-5.7). The associations between early SEP and type 2 diabetes disappeared after adjustment for adult SEP and factors associated with type 2 diabetes. CONCLUSION: The association between type 2 diabetes and low SEP during childhood and adolescence in middle-aged Swedish subjects disappeared after adjustment for adult SEP and adult risk factors of diabetes.

Association of TNF-alpha serum levels and TNFA promoter polymorphisms with risk of myocardial infarction.

Elevated levels of tumor necrosis factor-alpha (TNF-alpha), and presence of polymorphisms of the TNFA gene have been implicated in cardiovascular disease pathogenesis. We explored the relationship between polymorphisms in the TNFA gene (-1031C/T, -863C/A -857T/C, -308G/A, -238G/A), protein levels of TNF-alpha and their association to myocardial infarction (MI) using a sample of 1213 post-MI patients and 1561 healthy controls. MI risk was higher among men with elevated TNF-alpha levels, with the highest compared to the lowest TNF-alpha quartile giving a 70% risk increase (OR [95% CI]: 1.7 [1.1; 2.6]). Obese subjects who also had elevated TNF-alpha levels were at even higher risk for MI (OR [95% CI]: 3.4 [2.1; 5.6]). Higher TNF-alpha levels were seen among smokers (but not among non-smokers) carrying the -857T allele. Furthermore, a rare haplotype occurred more frequently among the cases than the controls. Elevated TNF-alpha levels are associated with increased MI risk. Obese subjects with elevated TNF-a levels, and carriers of polymorphisms in or near TNFA are particularly susceptible to the hazards of smoking, results which may have implications for cardiovascular preventive measures.

Accumulation of adverse socioeconomic position over the entire life course and the risk of myocardial infarction among men and women: results from the Stockholm Heart Epidemiology Program (SHEEP).

BACKGROUND: Accumulation of adverse socioeconomic position over the life course is assumed to increase the risk of myocardial infarction. OBJECTIVE: To analyse in detail whether the accumulation of adverse socioeconomic position over the life course increases the risk of myocardial infarction, using yearly information on individual socioeconomic position from birth to disease onset. DESIGN: Case-control study of risk factors for incident myocardial infarction (Stockholm Heart Epidemiology Program). SETTING: All Swedish citizens born during 1922-49 and living in Stockholm County during 1992-4. PARTICIPANTS: 550 female and 1204 male patients and 777 female and 1538 male controls. Every year in manual work was added to calculate a proportion of the whole life course spent in adverse socioeconomic position. RESULTS: With increasing proportion of life spent in adverse socioeconomic position, we found an increasing risk of myocardial infarction. The relative risk of myocardial infarction was 2.36 (95% confidence interval (CI) = 1.79 to 3.11) for men and 2.54 (95% CI = 1.70 to 3.78) for women who, over the entire life course, had always been in adverse socioeconomic position compared with those who had never been in adversity. We also found a strong increase in risk from being in adversity for only a few years, indicating important selection processes. CONCLUSIONS: Accumulated experience of adverse socioeconomic position over the entire life course increases the risk of myocardial infarction for men and women, but it is not a pure accumulation process as "how" and "when" the accumulation occurs also seems to have a role. The accumulation effect is partly mediated by the acquisition of health-damaging experiences.

Trends in occupational mortality among middle-aged men in Sweden 1961-1990.

BACKGROUND: Many European countries have in recent decades reported growing socioeconomic differentials in mortality. While these trends have usually paralleled high unemployment and increasing income disparities, Sweden had low unemployment and narrowing income differences. This study describes trends, 1961-1990, in total and cardiovascular mortality among men, 45-69 years of age, in major occupational classes in Sweden. METHODS: From census data four cohorts were created from those enumerated in 1960, 1970, 1980 and 1985. Through record linkage with the Swedish cause of death registry the mortality in each cohort was followed for 5-10 years. Age-standardized mortality trends 1961-1990 were calculated for occupational groups, categorized according to sector of the economy. RESULTS: The increase in mortality among middle-aged men in Sweden 1965-1980 was mainly a result of increasing cardiovascular mortality among industrial workers and farmers. In the 1980s the trend for these groups changed into a last decrease in mortality similar to that for non-manual occupations for the whole period. Consequently the rate ratio for industrial workers in comparison with men having a professional/managerial type of occupation increased from 0.98 to 1.43. The slowest decrease is now found among unqualified occupations in services and transportation. CONCLUSIONS: While Sweden, during the period studied, had narrowing income differentials and low unemployment this result points to the importance of working conditions in understanding trends and distribution of male adult mortality.

Socioeconomic differences in risk of myocardial infarction 1971-1994 in Sweden: time trends, relative risks and population attributable risks.

BACKGROUND: The general trend in incidence of myocardial infarction (MI) in the Stockholm area changed from increasing to decreasing around 1980. The objective of this study is to examine time trends in incidence in major socioeconomic strata, relative risk between socioeconomic groups and population risk attributable to socioeconomic differences during this period. METHODS: All cases of MI from 1971 to 1986 were identified from hospital discharge and cause-of-death registers. Person-years for each year of follow-up were calculated from the population register in the Stockholm region 1971-1986. Census registers were used for information on socioeconomic status. Register information was individually linked through the Swedish personal identification number. Supplementary information for 1992-1994 was taken from the case-control study SHEEP (Stockholm Heart Epidemiology Program). RESULTS: The decline in MI risk among male high- and middle-level employees started in 1976 and in male manual workers in 1981. For women incidence increased from 1971 to 1986 among manual workers and decreased among high- and middle-level employees. The increase over time of the relative risk from low socioeconomic position continued into the 1990s. Despite the reduction of the category of manual workers, the population attributable risk from socioeconomic differences also increased over time. The process of social change influencing the size of the socioeconomic groups contributes to the change in time trends of MI morbidity. CONCLUSIONS: The increase over time of relative and population attributable risks of MI from low socioeconomic status add to the public health importance of social inequity.

Is perceived failure in school performance a trigger of physical injury? A case-crossover study of children in Stockholm County.

OBJECTIVES: To investigate whether perceived failure in school performance increases the potential for children to be physically injured. SUBJECTS: Children aged 10-15 years residing in the Stockholm County and hospitalised or called back for a medical check up because of a physical injury during the school years 2000-2001 and 2001-2002 (n = 592). METHODS: A case-crossover design was used and information on potential injury triggers was gathered by interview. Information about family socioeconomic circumstances was gathered by a questionnaire filled in by parents during the child interview (response rate 87%). RESULTS: Perceived failure in school performance has the potential to trigger injury within up to 10 hours subsequent to exposure (relative risk = 2.70; 95% confidence intervals = 1.2 to 5.8). The risk is significantly higher among pre-adolescents and among children from families at a higher education level. CONCLUSIONS: Experiencing feelings of failure may affect children's physical safety, in particular among pre-adolescents. Possible mechanisms are perceptual deficits and response changes occasioned by the stress experienced after exposure.

Association between job characteristics and plasma fibrinogen in a normal working population: a cross sectional analysis in referents of the SHEEP Study. Stockholm Heart Epidemiology Program.

STUDY OBJECTIVE: To explore the association between job characteristics and plasma fibrinogen concentrations. DESIGN: Cross sectional design. SETTING: The Greater Stockholm area. SUBJECTS: A total of 1018 men and 490 women aged 45-70 who were randomly selected from the general population during 1992-1994. They were all employed and had no history of myocardial infarction. MAIN RESULTS: The self reported job characteristics were measured by a Swedish version of the Karasek demand-control questionnaire. For inferred scoring of job characteristics, psychosocial exposure categories (job control and psychological demands) were assigned by linking each subject's occupational history with a work organisation exposure matrix. Job strain was defined as the ratio between demands and control. In univariate analyses, expected linear trends were found in three of four tests of association between high plasma fibrinogen and low control (the self reported score for women and the inferred score for both sexes), in one of four tests of association between high plasma fibrinogen and high demands (the inferred score for women) and in two of four tests of association between high plasma fibrinogen and job strain (the inferred score for both sexes). Multiple logistic regression analyses showed that men in the inferred job strain group have an increased risk of falling into the increased plasma fibrinogen concentration group (above median level of the distribution) (odds ratio (OR) 1.2; 95% CI 1.0, 1.5) after adjustment for the variables that were associated with plasma fibrinogen in the univariate analyses. In women, low self reported control, high inferred demand, and inferred job strain were significantly associated with increased plasma fibrinogen concentration (OR 1.3; 95% CI 1.0, 1.8, OR 1.5; 95% CI 1.0, 2.2, OR 1.5; 95% CI 1.1, 2.2, respectively). CONCLUSIONS: These results indicate that adverse job characteristics may be related to plasma fibrinogen concentrations and this relation is more relevant in female workers. The clearest evidence for psychosocial effects on plasma fibrinogen seems to be with job control and the associations are clearer for the objective than for the self report variables.

Psychosocial work environment and myocardial infarction: improving risk estimation by combining two complementary job stress models in the SHEEP Study.

OBJECTIVES: Associations between two alternative formulations of job stress derived from the effort-reward imbalance and the job strain model and first non-fatal acute myocardial infarction were studied. Whereas the job strain model concentrates on situational (extrinsic) characteristics the effort-reward imbalance model analyses distinct person (intrinsic) characteristics in addition to situational ones. In view of these conceptual differences the hypothesis was tested that combining information from the two models improves the risk estimation of acute myocardial infarction. METHODS: 951 male and female myocardial infarction cases and 1147 referents aged 45-64 years of The Stockholm Heart Epidemiology (SHEEP) case-control study underwent a clinical examination. Information on job stress and health adverse behaviours was derived from standardised questionnaires. RESULTS: Multivariate analysis showed moderately increased odds ratios for either model. Yet, with respect to the effort-reward imbalance model gender specific effects were found: in men the extrinsic component contributed to risk estimation, whereas this was the case with the intrinsic component in women. Controlling each job stress model for the other in order to test the independent effect of either approach did not show systematically increased odds ratios. An improved estimation of acute myocardial infarction risk resulted from combining information from the two models by defining groups characterised by simultaneous exposure to effort-reward imbalance and job strain (men: odds ratio 2.02 (95% confidence intervals (CI) 1.34 to 3.07); women odds ratio 2.19 (95% CI 1.11 to 4.28)). CONCLUSIONS: Findings show an improved risk estimation of acute myocardial infarction by combining information from the two job stress models under study. Moreover, gender specific effects of the two components of the effort-reward imbalance model were observed.

Socioeconomic context in area of living and risk of myocardial infarction: results from Stockholm Heart Epidemiology Program (SHEEP).

STUDY OBJECTIVE: To analyse if socioeconomic characteristics in area of living affect the risk of myocardial infarction in a Swedish urban population, and to evaluate to what extent the contextual effect is confounded by the individual exposures. DESIGN: A population based case-referent study (SHEEP). SETTING: Cases (n=1631) were all incident first events of myocardial infarction during 1992-1994. The study base included all Swedish citizens aged 45-70 years, living in Stockholm metropolitan area during these years. The social context of all metropolitan parishes (n=89) was determined by routine statistics on 21 socioeconomic indicators. A factor analysis of the socioeconomic indicators resulted in three dimensions of socioeconomic deprivation, which were analysed separately as three different contextual exposures. MAIN RESULTS: The main characteristics of the extracted factors were; class structure, social exclusion and poverty. Among men, there were increased relative risks of similar magnitudes (1.28 to 1.33) in the more deprived areas according to all three dimensions of the socioeconomic context. However, when adjusting for individual exposures, the poverty factor had the strongest contextual impact. The contextual effects among women showed a different pattern. In comparison with women living the most affluent areas according to the class structure index, women in the rest of Stockholm metropolitan area had nearly 70% higher risk of myocardial infarction after adjustment for individual social exposures. CONCLUSIONS: The results suggest that the socioeconomic context in area of living increases the risk of myocardial infarction. The increased risk in only partially explained by individual social factors (the compositional effect).

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.

Time trends in the incidence of myocardial infarction among professional drivers in Stockholm 1977-96.

AIMS: To investigate time trends in the incidence of first myocardial infarction (MI) among bus, taxi, and lorry drivers in Stockholm. METHODS: In this population based case-control study, all first events of acute MI among men aged 40-69 in Stockholm County 1977-96 were identified using registers of hospital discharges and deaths. Controls were selected randomly from the general population. National censuses were used for information on occupational titles. A total of 20,364 cases and 136,342 controls were included in the study. Among these, 1183 cases and 6072 controls had worked as drivers. RESULTS: During 1977-84 the MI incidence was higher in all three driver groups than among other manual workers. There was a decline in MI incidence among drivers as well as in the general population during the study period. The decline was greater among drivers than among other manual workers. During 1985-96 the relative risk remained increased compared to other manual workers among taxi and lorry drivers, but not among bus drivers. CONCLUSIONS: Despite a reduced MI incidence for professional drivers in recent years, preventive measures to reduce the risk of MI in these occupational groups, and in particular among taxi and lorry drivers, continue to be of importance.