Empirical evidence of underutilization of referrals for epilepsy surgery evaluation.

BACKGROUND: Epilepsy surgery is a treatment that can cure patients with intractable epilepsy. This study investigates whether referrals for epilepsy surgery evaluation are underutilized. METHODS: Patients with epilepsy aged 18-60 years were identified in a computerized registry held by public health care providers in a Swedish county using ICD codes. Clinical data and data on referral status for epilepsy surgery were obtained from the patients' medical records. Potential candidates for epilepsy surgery evaluation were identified using pre-specified criteria. Obstacles for referral were analysed by comparing clinical data in patients who were considered for referral and those who were not. Appropriateness of non-referral was evaluated against recommendations from the Swedish Council on Technology in Health Care (SBU). RESULTS: Of 378 patients with epilepsy in the registry, 251 agreed to participate. Of 251, 40 were already referred patients and 48 patients were identified as potential candidates for epilepsy surgery evaluation by study criteria. Referral had been considered but not performed in 15 of the potential candidates. Potential candidates not considered for referral were less likely to have seen a neurologist, to have had an EEG, CT and MRI, and more likely to have cognitive disturbances. Following the recommendations by the SBU, 28 of 48 potential candidates were identified as inappropriately not referred patients. CONCLUSION: The number of missed referrals for epilepsy surgery evaluation was estimated to be 60 per 100,000 inhabitants. Several important obstacles were found for not referring patients for epilepsy surgery evaluation.

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.

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).

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.

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.

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.

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.

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.

Recent time trends in acute myocardial infarction in Stockholm, Sweden.

AIMS: The purpose of this study was to analyse time trends in first acute myocardial infarction (AMI) incidence in Stockholm County during 1984-1996. METHODS AND RESULTS: The study base consisted of the population of Stockholm County 30-89 years old 1984-1996. New cases of first AMI in the study base were identified by combining information regarding hospital discharges and deaths. The diagnostic quality was evaluated for 2403 First-AMI cases 45-70 years old that occurred during 1992-1994. The evaluation indicated a very high agreement with diagnostic criteria of AMI among hospital treated cases. Among fatal cases outside hospital, the autopsy rate was nearly 70%. The incidence of first AMI declined during the study period for both men and women. In men, the age-adjusted incidence of first AMI was 18% lower in 1994-1996 than in 1984-1987 and in women it was 13% lower. The average yearly decline was 2% for men and 1.4% for women. CONCLUSION: The results of this study suggest a continued decline in AMI incidence in Stockholm. A reduction in the proportion of regular smokers has probably contributed to this decline. Future trends in AMI incidence are difficult to predict in view of diverging trends in risk factors.

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.

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.

Do episodes of anger trigger myocardial infarction? A case-crossover analysis in the Stockholm Heart Epidemiology Program (SHEEP).

OBJECTIVE: Our objectives were to study anger as a trigger of acute myocardial infarction (MI) and to explore potential effect modification by usual behavioral patterns related to hostility. METHODS: This study was a case-crossover study within the Stockholm Heart Epidemiology Program. Exposure in the period immediately preceding MI was compared with exposure during a control period for each case. From April 1993 to December 1994, 699 patients admitted to coronary care units in Stockholm County were interviewed. RESULTS: During a period of 1 hour after an episode of anger, with an intensity of at least "very angry," the relative risk of MI was 9.0 (95% CI, 4.4-18.2). In patients with premonitory symptoms, the time of disease initiation may be misclassified. When restricting the analyses to those without such symptoms, the trigger risk was 15.7 (95% CI, 7.6-32.4). The possibility of examining effect modification was limited by a lack of statistical power (eight exposed cases). Results of the analyses suggested, however, an increased trigger effect among subjects reporting nonhostile usual behavior patterns, nonovert strategies of coping with aggressive situations (not protesting when being treated unfairly), and nonuse of beta-blockers. CONCLUSIONS: The hypothesis that anger may trigger MI is further supported, with an increased risk lasting for approximately 1 hour after an outburst of anger. It is suggested that the trigger risk may be modified by personal behavior patterns.

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.

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.

Shiftwork and myocardial infarction: a case-control study.

OBJECTIVES: Previous studies have indicated an association between shiftwork and coronary heart disease. The increased risk could be due to job strain, which could act as a mediator of disease. There is also a possibility that interaction between shiftwork and job strain could occur that may induce or modify the development of disease. We conducted this study to explore the relation between shiftwork, job strain, and myocardial infarction. METHODS: 2006 cases with acute first time myocardial infarction were compared with 2642 controls without symptoms of myocardial infarction, and obtained from the same population that gave rise to the cases (population based case-control study). RESULTS: Myocardial infarction risk was associated with shiftwork both in men (odds ratio (OR) 1.3, 95% confidence interval (95% CI) 1.1 to 1.6) and women (OR 1.3, 95% CI 0.9 to 1.8). In the age group 45-55, the relative risk was 1.6 in men and 3.0 in women. The results cannot be explained by job strain, age, job education level, or smoking. No interaction was found between shiftwork and job strain. CONCLUSIONS: The findings indicate that shiftwork is associated with myocardial infarction in both men and women. The mechanism is unclear, but the relation cannot be explained by job strain, smoking, or job education level.

Mortality and cancer incidence among laboratory technicians in medical research and routine laboratories (Sweden).

OBJECTIVES: To investigate cancer incidence and mortality among laboratory employees. METHODS: Mortality and cancer incidence were investigated among 2553 female and male laboratory workers employed at the Karolinska Institute and Karolinska Hospital in Stockholm between 1950 and 1989. Mortality was followed from 1952-1993 and cancer incidence from 1958-1992. Expected numbers were based on the general population in Stockholm, standardizing for age, gender, and calendar period. RESULTS: The overall mortality and cancer incidence in the cohort was lower than expected. There were in all 10 cases of hemato-lymphatic malignancies (three acute myeloid leukemias, four non-Hodgkin lymphomas, two Hodgkin's lymphomas, and one multiple myeloma) in the cohort. The standardized incidence ratio (SIR) for hematolymphatic tumors was increased among workers who had ever been employed in laboratories with a high probability for chemical exposure, SIR 224 (95% CI 108-412). The risk of breast cancer among women was increased after more than 10 years of work in high-exposure laboratories, SIR 225 (128-365). The number of malignant melanomas exceeded those expected. CONCLUSIONS: The findings support earlier observations of an increased risk of hematolymphatic cancer among laboratory workers. The routine for handling chemicals and functionality of ventilatory equipment must be under continuous supervision.

Myocardial infarction in male and female dominated occupations.

The aim of the study was to investigate whether workers in jobs dominated by the opposite sex have an increased risk of myocardial infarction (MI). A case-referent study was carried out to estimate the relative risk of first MI in different occupational groups. The study base comprised all men and women in five counties in the middle of Sweden during 1976-84. Cases of MI were identified from both hospital discharge records and death records. Information on occupation was obtained from two consecutive censuses. Primary health related selection was analysed for men with data from the physical examination of conscripts to compulsory military service in 1969-70 combined with data from the censuses of 1970-90 and data on early retirement in 1971-92. Increased risk of MI was found among both women (relative risk (RR) 1.41, 95% confidence interval (95% CI) 1.15 to 1.73) and men (1.21, 1.10 to 1.32) in blue collar jobs where men predominate, and among men with white collar jobs (1.26, 1.09 to 1.45) where women predominate. However, the increased risk among men in white collar jobs was probably due to negative health selection into these occupations. These results do not support the notion that being of the sexual minority in an occupation is in itself an important risk factor for MI.

Cancer predictive value of cytogenetic markers used in occupational health surveillance programs: a report from an ongoing study by the European Study Group on Cytogenetic Biomarkers and Health.

The cytogenetic endpoints in peripheral blood lymphocytes: chromosomal aberrations (CA), sister chromatid exchange (SCE) and micronuclei (MN) are established biomarkers of exposure for mutagens or carcinogens in the work environment. However, it is not clear whether these biomarkers also may serve as biomarkers for genotoxic effects which will result in an enhanced cancer risk. In order to assess this problem, Nordic and Italian cohorts were established, and preliminary results from these two studies indicated a predictive value of CA frequency for cancer risk, whereas no such associations were observed for SCE or MN. A collaborative study between the Nordic and Italian research groups, will enable a more thorough evaluation of the cancer predictivity of the cytogenetic endpoints. We here report on the establishment of a joint data base comprising 5271 subjects, examined 1965-1988 for at least one cytogenetic biomarker. Totally, 3540 subjects had been examined for CA, 2702 for SCE and 1496 for MN. These cohorts have been followed-up with respect to subsequent cancer mortality or cancer incidence, and the expected values have been calculated from rates derived from the general populations in each country. Stratified cohort analyses will be performed with respect to the levels of the cytogenetic biomarkers. The importance of potential effect modifiers such as gender, age at test, and time since test, will be evaluated using Poisson regression models. The remaining two potential effect modifiers, occupational exposures and smoking, will be assessed in a case-referent study within the study base.

Chromosomal aberrations in lymphocytes predict human cancer: a report from the European Study Group on Cytogenetic Biomarkers and Health (ESCH).

Chromosomal aberrations (CAs), sister chromatid exchanges (SCEs), and micronuclei (MN) in peripheral blood lymphocytes have for decades been used as cytogenetic biomarkers to survey genotoxic risks in the work environment. The conceptual basis for this application has been the idea that increased cytogenetic damage reflects an enhanced cancer risk. Nordic and Italian cohorts have been established to evaluate this hypothesis, and analyses presented previously have shown a positive trend between CA frequency and increased cancer risk. We now report on a pooled analysis of updated data for 3541 subjects examined for CAs, 2703 for SCEs, and 1496 for MN. To standardize for interlaboratory variation, the results for the various cytogenetic end points were trichotomized on the basis of the absolute value distribution within each laboratory as "low" (1-33 percentile), "medium" (34-66 percentile), or "high" (67-100 percentile). In the Nordic cohort, there was an elevated standardized incidence ratio (SMR) for all cancer among subjects with high CA frequency [1.53; 95% confidence interval (CI), 1.13-2.05] but not for those with medium or low CA frequency. In the Italian cohort, a SMR in cancer of 2.01 (95% CI, 1.35-2.89) was obtained for those with a high CA frequency level, whereas the SMRs for those with medium or low did not noticeably differ from unity. Cox's proportional hazards models gave no evidence that the effect of CAs on total cancer incidence/mortality was modified by gender, age at test, or time since test. No association was seen between the SCEs or the MN frequencies and subsequent cancer incidence/mortality. The present study further supports our previous observation on the cancer predictivity of the CA biomarker, which seems to be independent of age at test, gender, and time since test. The risk patterns were similar within each national cohort. This result suggests that the frequency of CAs in peripheral blood lymphocytes is a relevant biomarker for cancer risk in humans, reflecting either early biological effects of genotoxic carcinogens or individual cancer susceptibility.