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Biomedical subjects

J Hallqvist

Publications and source records attributed to J Hallqvist.

At least 19 recordsLinked to original sources
PubMed2006

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.

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PubMed2005

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.

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PubMed2004

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.

Adolescent↗
PubMed2004

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.

Adult↗
PubMed2003

Association of boiled and filtered coffee with incidence of first nonfatal myocardial infarction: the SHEEP and the VHEEP study.

OBJECTIVES: To evaluate the influence of consumption of filtered and boiled coffee, on the incidence of first nonfatal myocardial infarction. DESIGN: Population-based case-control study. SETTING AND SUBJECTS: The study base consisted of the population 45-65/70 years-old in two Swedish counties, Stockholm and Västernorrland, 1992/93-94. In all, 1943 cases of first nonfatal myocardial infarction were identified. For each case one control was selected from the study base concurrently with disease incidence by matching the sex, age and place of residence of the case. Information about coffee consumption and other factors was obtained by mailed questionnaire and a medical examination. The participation rate was 85% amongst cases and 74% amongst controls. RESULTS: Men with a reported consumption of 7-9 dL filtered coffee per day showed an increased incidence of first myocardial infarction compared with consumers of 3 dL day-1 or less (RR: 1.32; 95% CI: 1.03-1.70). A consumption of at least 10 dL day-1 was associated with an RR of 1.93 (95% CI: 1.42-2.63) for filtered and 2.20 (95% CI: 1.17-4.15) for boiled coffee. Amongst women, no clear association was seen between consumption of filtered coffee and myocardial infarction but consumption of boiled coffee tended to be related to an increased incidence. Comparing subjects drinking boiled coffee with those drinking filtered coffee and adjusting for the amount consumed gave an increased incidence for boiled coffee amongst both men (RR: 1.41; 95% CI: 1.07-1.80) and women (RR: 1.63; 95% CI: 1.04-2.56). CONCLUSIONS: Consumption of boiled coffee appears to increase the incidence of first nonfatal myocardial infarction. This increased incidence is consistent with randomized trials showing an adverse impact of boiled coffee on blood lipids.

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PubMed2002

Bullying in the school environment: an injury risk factor?

OBJECTIVE: To describe a research project assessing the role of bullying at school as an injury trigger and the modification effect of the socio-economic environment of the victims. Preliminary results are also presented. METHOD: A case-crossover and a case-referent design were combined. The study base consisted of all children aged 10-15 years residing in the Stockholm county in 2000-02. Cases were recruited at the county's children hospital and interviewed shortly after the injury, using a specially designed questionnaire. RESULTS: Preliminary analyses (261 interviews) reveal that about two injured children out of 10 reported having been bullied during the school term. Also, one out of 10 had been bullied shortly enough before the injury for bullying to be considered as a trigger. The circumstances of occurrence of those injuries varied. CONCLUSION: Bullying, apart from being frequent in the school environment, is quite likely to act as an injury trigger.

Adolescent↗
PubMed2002

The G-455A polymorphism of the fibrinogen Bbeta-gene relates to plasma fibrinogen in male cases, but does not interact with environmental factors in causing myocardial infarction in either men or women.

OBJECTIVES: To elucidate the association between a genetic polymorphism of the fibrinogen Bbeta-gene (G-455A) and plasma fibrinogen levels and myocardial infarction (MI), respectively. In addition, to explore potential synergistic gene-environment interactions involving this polymorphism--until now, these data were unavailable. DESIGN SETTING AND SUBJECTS: This case-referent study of subjects aged 45-70 and living in Stockholm includes 834 men and 346 women with first-time MI and 1034 men and 494 women randomly chosen as referents from the population. The cases were identified between 1992 and 1994 at the 10 emergency hospitals in Stockholm County. MAIN OUTCOME MEASURES: MI and plasma fibrinogen levels. RESULTS: Crude analyses associated a high level of plasma fibrinogen with an increased risk of MI in both men and women. However, the relative risk decreased after controlling for other risk factors. The multivariate-adjusted odds ratio (OR) (95% confidence interval) was 1.6 (1.2-2.3) for men and 1.5 (0.9-2.6) for women. Presence of the A allele at the G-455A polymorphic site indicated higher plasma fibrinogen levels than the presence of the G allele, but the difference was only statistically significant for male cases. The -455A allele was not associated with an increased risk of MI. Furthermore, there were no strong indications of synergistic interaction between the G-455A polymorphism and any of the environmental exposures considered. CONCLUSIONS: In this large number of MI cases and referents, a high level of plasma fibrinogen was independently associated with increased risk of MI in men but not in women. The presence of the A allele at the G-455A polymorphism of the fibrinogen Bbeta-gene was not associated with increased risk of MI, and no synergistic gene-environment interactions were detected.

Age Factors↗
PubMed2002

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).

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PubMed2002

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.

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PubMed2001

Geographical differences in the incidence of acute myocardial infarction in Sweden. Analyses of possible causes using two parallel case-control studies.

OBJECTIVES: To analyse differences in myocardial infarction incidence between two Swedish counties and to evaluate the importance of major risk factors for the observed differences. DESIGN: The incidence of first myocardial infarction was studied using information from registers. For a number of risk factors of myocardial infarction, the prevalence as well as the relative risk was estimated from population controls of case-control studies in the two areas. SUBJECTS: Men and women aged 45-64 years in Stockholm and Västernorrland County 1993-94. MAIN OUTCOME MEASURES: Relative risks (RRs) and impact fractions were used to evaluate the importance of differences in risk factor prevalence for differences in myocardial infarction incidence between the two areas. RESULTS: The incidence of first myocardial infarction was higher in Västernorrland than in Stockholm amongst both men (RR = 1.23; 95% CI = 1.08-1.40) and women (RR = 1.41; 95% CI = 1.11-1.79). Obesity and increased levels of blood serum lipids were more prevalent in Västernorrland than in Stockholm amongst men with impact fractions of 6 and 9-11%, respectively. Amongst women, corresponding differences were not seen, but job strain and shift work tended to be more common in the more northern area. Current smoking was more frequent in Stockholm, particularly for women. CONCLUSIONS: The incidence of first myocardial infarction was higher in Västernorrland than in Stockholm in both genders. A higher prevalence of obesity and elevated blood serum lipids may explain, in part, this excess incidence amongst men, but amongst women the causes of the higher incidence in the more northern area remain largely unclear.

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PubMed2001

Family history of coronary heart disease, a strong risk factor for myocardial infarction interacting with other cardiovascular risk factors: results from the Stockholm Heart Epidemiology Program (SHEEP).

We explored the relation between family history of coronary heart disease and the risk of myocardial infarction in a case-control study of subjects, 45 to 70 years of age, living in Stockholm, Sweden. Our cases comprised 1091 male and 531 female first-time acute myocardial infarction patients who had survived at least 28 days after their infarction. Referents were randomly selected from the population from which the cases were derived. The adjusted odds ratio (OR) of myocardial infarction was 2.0 (95% confidence interval [CI] = 1.6-2.6) for men reporting > or = 1 affected parent or sibling, compared with men with no family history of coronary heart disease, and 3.4 (95% CI = 2.1-5.9) for those reporting > or = 2 affected parents or siblings. The corresponding OR for women were 2.1 (95% CI = 1.5-3.0) and 4.4 (95% CI = 2.4-8.1). We found evidence for synergistic interactions in women exposed to family history of coronary heart disease in combination with current smoking and with a high quotient between low-density lipoprotein and high-density lipoprotein cholesterol (>4.0), respectively, which yielded adjusted synergy index scores of 2.9 (95% CI = 1.2-7.2) and 3.8 (95% CI = 1.5-9.7), respectively. Similarly, in men we found evidence for interaction for the co-exposure of family history of coronary heart disease and diabetes mellitus. Our study shows that family history of coronary heart disease is not only a strong risk factor for myocardial infarction in both sexes, but that its effect is synergistic with other cardiovascular risk factors as well.

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PubMed2001

A population-based case-referent study of myocardial infarction and occupational exposure to motor exhaust, other combustion products, organic solvents, lead, and dynamite. Stockholm Heart Epidemiology Program (SHEEP) Study Group.

This case-referent study investigated the risk of myocardial infarction from occupational exposure to motor exhaust, other combustion products, organic solvents, lead, and dynamite. We identified first-time, nonfatal myocardial infarctions among men and women 45-70 years of age in Stockholm County from 1992 through 1994. We selected referent subjects from the population to match the demographic characteristics of the cases. A lifetime history of occupations was obtained by questionnaire. The response rate was 81% for the cases and 74% for the referents, with 1,335 cases and 1,658 referents included in the study. An occupational hygienist assessed occupational exposures, coding the intensity and probability of exposure for each subject. We adjusted relative risk estimates for tobacco smoking, alcohol drinking, hypertension, diabetes mellitus, overweight, and physical inactivity at leisure time. The relative risk of myocardial infarction was 2.11 (95% confidence interval = 1.23-3.60) among those who were highly exposed and 1.42 (95% confidence interval = 1.05-1.92) among those who were intermediately exposed to combustion products from organic material. We observed an exposure-response pattern, in terms of both maximum exposure intensity and cumulative dose. Exposure to dynamite and organic solvents was possibly associated with an increased risk. The other exposures were not consistently associated with myocardial infarction.

Aged↗
PubMed2001

Environmental tobacco smoke and myocardial infarction among never-smokers in the Stockholm Heart Epidemiology Program (SHEEP).

An increased risk for myocardial infarction (MI) related to environmental tobacco smoke (ETS) exposure has previously been reported, but several aspects of the association are still uncertain. We studied the MI risk associated with ETS exposure among 334 nonfatal never-smoking MI cases and 677 population controls, 45-70 years of age, in Stockholm County. A postal questionnaire with a telephone follow-up provided information on ETS exposure and other potential risk factors for MI. After adjustment for age, gender, hospital catchment area, body mass index, socioeconomic status, job strain, hypertension, diet, and diabetes mellitus, the odds ratio for MI was 1.58 (95% confidence interval = 0.97-2.56) for an average daily exposure of 20 cigarettes or more from the spouse. Combined exposure from spouse and work showed an increasing odds ratio for MI, up to 1.55 (95% confidence interval = 1.02-2.34) in the highest category of weighted duration, that is, more than 90 "hour-years" of exposure (1 "hour-year" = 365 hours, or 1 hour per day for 1 year). In addition, more recent exposure appeared to convey a higher risk. Our data confirm an increased risk of MI from exposure to ETS and suggest that intensity of spousal exposure, combined exposure from spouse and work, and time since last exposure are important.

Age Distribution↗
PubMed2001

Sexual activity as a trigger of myocardial infarction. A case-crossover analysis in the Stockholm Heart Epidemiology Programme (SHEEP).

OBJECTIVE: To investigate sexual activity as a trigger of myocardial infarction and the potential effect modification of physical fitness. DESIGN: A case-crossover study nested in the Stockholm Heart Epidemiology Programme (SHEEP). SETTING: Stockholm County from April 1993 to December 1994. PATIENTS: All patients with a first episode of non-fatal acute myocardial infarction admitted to coronary care units were eligible, and 699 patients participated in an interview. MAIN OUTCOME MEASURES: Relative risks with 95% confidence intervals. RESULTS: Only 1.3% of the patients without premonitory symptoms had sexual activity during two hours before the onset of myocardial infarction. The relative risk of myocardial infarction was 2.1 (95% confidence interval (CI) 0.7 to 6.5) during one hour after sexual activity, and the risk among patients with a sedentary life was 4.4 (95% CI 1.5 to 12.9). CONCLUSIONS: The increased risk of myocardial infarction after sexual activity and the further increase in risk among the less physically fit support the hypothesis of causal triggering by sexual activity. However, the absolute risk per hour is very low, and exposure is relatively infrequent. Thus having sex once a week only increases the annual risk of myocardial infarction slightly. Counselling should focus on encouraging patients to live a physically active life and not on abstaining from sexual activity.

Coitus↗
PubMed2000

Does heavy physical exertion trigger myocardial infarction? A case-crossover analysis nested in a population-based case-referent study.

To study possible triggering of first events of acute myocardial infarction by heavy physical exertion, the authors conducted a case-crossover analysis (1993-1994) within a population-based case-referent study in Stockholm County, Sweden (the Stockholm Heart Epidemiology Program). Interviews were carried out with 699 myocardial infarction patients after onset of the disease. These cases represented 47 percent of all cases in the study base, and 70 percent of all nonfatal cases. The relative risk from vigorous exertion was 6.1 (95% confidence interval: 4.2, 9.0). The rate difference was 1.5 per million person-hours, and the attributable proportion was 5.7 percent. The risk was modified by physical fitness, with an increased risk being seen among sedentary subjects as in earlier studies, but the data also suggested a U-shaped association. In addition, the trigger effect was modified by socioeconomic status. Premonitory symptoms were common, and this implies risks of reverse causation bias and misclassification of case exposure information that require methodological consideration. Different techniques (the use of the usual-frequency type of control information, a pair-matched analysis, and a standard case-referent analysis) were applied to overcome the threat of misclassification of control exposure information. A case-crossover analysis in a random sample of healthy subjects resulted in a relative risk close to unity, as expected.

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PubMed2000

Plasma levels of tissue plasminogen activator/plasminogen activator inhibitor-1 complex and von Willebrand factor are significant risk markers for recurrent myocardial infarction in the Stockholm Heart Epidemiology Program (SHEEP) study.

An impaired fibrinolytic function due to elevated plasma levels of plasminogen activator inhibitor (PAI)-1 activity or tissue plasminogen activator (tPA) antigen is correlated with the development of myocardial infarction (MI) in patients with manifest coronary heart disease. Recently, methods for determining the specific tPA/inhibitor complexes constituting tPA antigen in plasma have become available. In the Stockholm Heart Epidemiology Program (SHEEP) study, 86 of 1212 MI patients, subjected to blood sampling in a metabolically stable period, suffered reinfarction before the end of 1996. These individuals have been compared with an approximately equal number of matched MI patients without recurrence and a group of matched healthy control subjects regarding the plasma concentrations of some hemostatic factors. The hemostatic compounds studied (fibrinogen, von Willebrand factor, tPA antigen, PAI-1, and the tPA/PAI-1 complex) were typically higher in the groups (men and women) with recurrence of MI compared with those without. The plasma concentrations were also typically higher in the pooled groups of patients compared with the groups of healthy control subjects. The largest between-group differences were found for the plasma tPA/PAI-1 complex. The crude odds ratio for reinfarction associated with higher concentration (>/=75th percentile among the control subjects) of tPA/PAI-1 was 1.8 (95% CI 1.1 to 3.1); the corresponding crude odds ratio for von Willebrand factor was 2.3 (1. 3 to 4.0). The tPA/PAI-1 complex correlated strongly with PAI-1 and tPA antigen in all groups and with serum triglycerides and body mass index in all groups except for women with reinfarction. An increased plasma level of tPA/PAI-1 complex is a novel risk marker for recurrent MI in men and women. Most likely, increased plasma levels of tPA/PAI-1 complex reflect impaired fibrinolysis, because the correlation with PAI-1 is strong. Further support is obtained indicating that the plasma concentration of von Willebrand factor is also an important risk marker for recurrent MI.

Aged↗
PubMed1999

Higher relative, but lower absolute risks of myocardial infarction in women than in men: analysis of some major risk factors in the SHEEP study. The SHEEP Study Group.

OBJECTIVES: Middle-aged men have often been the subjects of multifactorial studies of myocardial infarction (MI) risk factors. One major objective of the SHEEP study was to compare the effects of different MI risk factors in women and men. DESIGN: SHEEP (Stockholm Heart Epidemiology Program) is a population-based case-referent study of causes of MI (first event) in Swedish women and men aged 45-70 years. During the period 1992-94, 2246 cases of MI were identified; 34% of the cases were women and 27% of the cases were fatal. One referent per case was chosen randomly from the Stockholm County population after stratification for the case's sex and age. Logistic regression was used to estimate the relative risks associated with risk factors of primary interest (diabetes, hypercholesterolaemia, hypertriglyceridaemia, hypertension, overweight, physical inactivity, smoking and job strain). RESULTS: The relative risk estimates ranged from 1.5 to 4.4 in women and from 1.3 to 2.9 in men (results for nonfatal cases and their referents). None of the 95% confidence intervals included 1.0. The relative risks were higher in the women than in the men (101-180%). The absolute risks, however, were all lower in the women than in the men. Estimates of Rothman's synergy index for gender ranged from 1.0 (hypertension) to 1.8 (current smoking). CONCLUSIONS: The indications of some effect modification due to sex (stronger risks in men for certain exposures) invoke the question of possible mechanisms.

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