Risk factors for myocardial infarct: a case-control study in Oporto, Portugal

A case-control study of coronary heart disease (CHD) was conducted in Oporto, Portugal. The cases series consisted of 100 consecutive patients with first time acute myocardial infarction who were admitted to the Coronary and Intermediate Care Units of a major teaching hospital. The community controls were 198 individuals without evidence of CHD by the Rose questionnaire and electrocardiography, selected by random digit dialing, with a participation rate of 70%. Data was collected by trained interviewers using a structured questionnaire and blood samples were obtained for selected laboratory data. The main analysis was made through unconditional logistic regression with calculations of odds ratios (OR). Age, OR: 1.5 (95% CI: 0.8-2.9), male gender, OR: 6.7 (3.6-12.3), family history of premature CHD, OR: 2.4 (1.4-4.3), diabetes, OR: 3.4 (1.6-7.4), antecedents of hypertension, OR:1.9 (1.1-3.1), history of high cholesterol levels, OR: 2.3 (1.4-3.9), high levels of physical activity, OR: 2.0 (0.9-4.1) and tobacco smoking, OR: 8.3 (3.8-18.5) were significant risk factors of acute myocardial infarction. After controlling for demographic variables and for the mutual confounding effects of the risk factors, the investigated factors that remained significantly associated with the risk of developing acute myocardial infarction were male gender, OR: 17.3 (4.8-62.3), family history of CHD, OR: 3.6 (1.4-9.6), diabetes, OR: 4.2 (1.0-18.1), high cholesterol levels OR: 2.7 (1.2-6.1) and smoking habits, OR: 7.7 (1.8-32.4). A negative association with high education levels was significant after controlling for all the variables, OR: 0.01 (0.01-0.5).     

Working hours as a risk factor for acute myocardial infarction in Japan: case-control study

OBJECTIVE: To clarify the extent to which working hours affect the risk of acute myocardial infarction, independent of established risk factors and occupational conditions. DESIGN: Case-control study. SETTING: University and general hospitals and routine medical examinations at workplaces in Japan. SUBJECTS: Cases were 195 men aged 30-69 years admitted to hospital with acute myocardial infarction during 1990-3. Controls were 331 men matched at group level for age and occupation who were judged to be free of coronary heart diseases at routine medical examinations in the workplace. MAIN OUTCOME MEASURES: Odds ratios for myocardial infarction in relation to previous mean daily working hours in a month and changes in mean working hours during previous year. RESULTS: Compared with men with mean working hours of >7-9 hours, the odds ratio of acute myocardial infarction (adjusted for age and occupation) for men with working hours of >11 hours was 2.44 (95% confidence interval 1.26 to 4.73) and for men with working hours of <=7 hours was 3.07 (1.77 to 5.32). Compared with men who experienced an increase of <=1 hour in mean working hours, the adjusted odds ratio of myocardial infarction for men who experienced an increase of >3 hours was 2.53 (1.34 to 4. 77). No appreciable change was observed when odds ratios were adjusted for established and psychosocial risk factors for myocardial infarction. CONCLUSION: There was a U shaped relation between the mean working hours and the risk of acute myocardial infarction. There also seemed to be a trend for the risk of infarction to increase with greater increases in mean working hours.     

Risk factors for multiple sclerosis: a case-control study in Israel

This case-control study was aimed at identifying environmental risk factors for multiple-sclerosis (MS). Ninety-three Israeli-born MS patients identified in country-wide studies and 94 age- and sex-matched controls were interviewed. The questionnaire covered a large span of factors at ages 0, 10 and onset of the disease, with particular emphasis on socioeconomic status (SES) and sanitary conditions (SAN). A significantly larger percentage of patients reported frequent respiratory educational levels than controls. The SES and SAN at age 10 were also systematically higher among patients, but significance was reached only when the frequencies of conditions indicating extremely low values of SES or SAN were compared. It is possible that the protective effect of low SES or SAN on risk of MS can be detected only when living conditions are well below average, as is frequent in developing countries.     

Risk factors for myocardial infarction in young women

Seventy-seven women discharged from hospital with a diagnosis of myocardial infarction and 207 control patients were investigated. All were under 45 years of age at the time of admission. Heavy cigarette smoking, reported treatment for pre-eclamptic toxaemia, and type II hyperlipoproteinaemia were found to be independent risk factors for myocardial infarction. Reported treatment for hypertension and diabetes are probably also independently associated with subsequent development of the condition, but the associations between myocardial infarction and reported treatment for obesity and psychiatric illness appear to be secondary. Previous publications have suggested that use of oral contraceptives is an independent risk factor. Examination of the effect of several factors combined, suggests that they act synergistically, the presence of three or more factors increasing the risk 128-fold.     

Risk factors for homelessness among schizophrenic men: a case-control study

OBJECTIVES: To identify risk factors for homelessness among the severely mentally ill, we conducted a case-control study of 100 indigent schizophrenic men meeting criteria for literal homelessness and 100 such men with no homeless history. METHODS: Subjects were recruited from shelter, clinic, and inpatient psychiatric programs in Upper Manhattan. Clinical interviewers employed standardized research instruments to probe three domains of risk factors: severity of mental illness, family background, and prior mental health service use. RESULTS: Homeless subjects showed significantly higher levels of positive symptoms, higher rates of a concurrent diagnosis of drug abuse, and higher rates of antisocial personality disorder. Homeless subjects experienced greater disorganization in family settings from birth to 18 years and less adequate current family support. Fewer homeless subjects than subjects in the never-homeless comparison group had a long-term therapist. These differences remained when demographic variables were adjusted statistically. CONCLUSIONS: Homeless schizophrenic men differed from their domiciled counterparts in all three domains we investigated; family background, nature of illness, and service use history. Findings are discussed in relation to policy and programs for the severely mentally ill.     

Risk factors for prosthetic joint infection: case-control study

Topology-representing neural networks are employed to generate pseudo-atomic structures of large-scale protein assemblies by combining high-resolution data with volumetric data at lower resolution. As an application example, actin monomers and structural subdomains are located in a three-dimensional (3D) image reconstruction from electron micrographs. To test the reliability of the method, the resolution of the atomic model of an actin polymer is lowered to a level typically encountered in electron microscopic reconstructions. The atomic model is restored with a precision nine times the nominal resolution of the corresponding low-resolution density. The presented self-organizing computing method may be used as an information-processing tool for the synthesis of structural data from a variety of biophysical sources.     

Risk factors for rifampin-monoresistant tuberculosis: A case-control study

Rifampin is the cornerstone of short-course chemotherapy for the treatment of tuberculosis (TB). Rifampin monoresistance (RMR) is less common than resistance to isoniazid alone or in combination with other antituberculous medications. We conducted a retrospective case-control study to identify risk factors for RMR-TB. Complete records for 21 of a total of 26 RMR patients from 1990 to 1997 were available for review, and were compared with those of 48 patients with drug-susceptible TB, controlling for year of diagnosis. Cases more frequently had a history of TB than did controls (61% versus 22%, p < 0.01), and were more often human immunodeficiency virus (HIV) positive (81% versus 46%, p = 0.02). With control for HIV status, cases were more likely to have extrapulmonary involvement (47.6% versus 11.6%, p = 0.05). Four cases (19%) and one control (2. 1%) died (p = 0.02) during hospitalization. Cases more often had a history of incarceration (71.4% versus 37.5%, p = 0.09). Among the 13 cases with a history of TB, five had evidence of malabsorption (vomiting and/or diarrhea), versus none of the 11 controls with prior TB. These data support the hypothesis that RMR is seen primarily in individuals with a history of TB and who are HIV positive. Cases were frequently noncompliant with previous treatment for TB, had a history of incarceration, and had poor outcomes.     

Decaffeinated coffee and acute myocardial infarction. A case-control study in Italian women

The relationship between consumption of decaffeinated coffee and acute myocardial infarction was analyzed in a case-control study conducted in Italy between 1983 and 1992. Case patients were 433 women with acute myocardial infarction, aged 24 to 69 years (median age, 52 years), and control subjects included 869 women in hospital for a wide spectrum of acute conditions, other than cardiovascular, neoplastic, digestive, and hormone-related diseases or conditions associated with long-term modification of diet. Regular use of decaffeinated coffee was reported by 11% of the case patients and 7% of the control subjects. Compared with women who did not drink decaffeinated coffee, the relative risk (RR) was 1.3 (95% confidence interval (CI), 0.8 to 2.2) for one cup/d and 2.1 (95% CI, 1.1 to 3.9) for 2 or more cups (chi 2(1) for trend = 5.62, P = 0.02). The estimates were somewhat higher after allowance for education, marital status, body mass index, and smoking status (RR for > or = 2 cups of decaffeinated coffee per day, 2.5; 95% CI, 1.2 to 4.9), and somewhat lower after further allowance for diabetes, hypertension, and hyperlipidemia (RR, 1.7; 95% CI, 0.8 to 3.6). There was no association between duration of use of decaffeinated coffee and infarction risk. The relationship between decaffeinated coffee and infarction was consistent across strata of age, education, smoking, and history of hyperlipidemia. Thus, a relationship of marginal significance was observed in this study between decaffeinated coffee and myocardial infarction, of similar magnitude to that described for caffeinated coffee. This indicates that (i) caffeine is unlikely to be a relevant factor in any potential coffee-myocardial infarction relationship, and (ii) shifting from caffeinated to decaffeinated coffee is unjustified in order to reduce any possible coffee-related infarction risk.     

Body weight and risk of nonfatal acute myocardial infarction among women: a case-control study from northern Italy

BACKGROUND: The relationship between nonfatal acute myocardial infarction (AMI) and self-reported body weight and body mass index (BMI; Quetelet index, kg/m2) has been investigated. METHODS: A case-control study was conducted between 1983 and 1992 in northern Italy on 432 women with nonfatal AMI and 867 controls in hospital for acute, noncardiovascular, nonneoplastic, nondigestive, non-hormone-related conditions. Odds ratios (OR), with their 95% confidence intervals (CI), were computed by unconditional multiple logistic regression analysis, including terms for age, education, and smoking, plus history of selected diseases. RESULTS: Women with body weight and BMI in the highest quartile had an increased risk of AMI after allowance for age, education, and smoking status (OR 1.5, 95% CI 1.0 to 2.2, and OR 1.7, 95% CI 1.2 to 2.4, respectively). Compared with leaner women, the risk was higher among women with BMI above the median, in association with a history of diabetes (OR 5.2) or hyperlipidemia (OR 6.0). Hypertensive women had similar OR in the two strata of BMI (OR 5.1 and 4.8). The association of BMI with risk of AMI was apparently stronger among women younger than 50 years and among less educated women, but was similar among smokers and never smokers. CONCLUSIONS: The results of this study confirm that AMI among women is related to excess BMI, with a population attributable risk of 17%. The excess risk was substantial among overweight women with history of diabetes or hyperlipidemia, stressing the importance of controlling body weight among these women.     

Risk factors for clinically diagnosed Alzheimer's disease: a case-control study of a Greek population

Many efforts have been made to trace the causes of Alzheimer's disease (AD). There are, however, many points of controversy among reports from the same country as well as among reports from different countries. The current study is a case-control study to determine the risk factors in the development of AD in Greece. Sixty-five patients with AD and 69 age-matched controls were examined. All patients with AD fulfilled the DSM-IV criteria for AD and NINCDS-ADRDA criteria for probable AD. Demographic characteristics such as gender, current marital status, who he/she is living with, education, main place of residence in childhood, adulthood, and late life, occupational hazards, patient's medical history (history of diabetes mellitus and hypertension), life habits like alcohol consumption and smoking, and a history of head trauma, heart attack, stroke, parkinsonism, or depression were collected from the subject or from an informant. A family history of selected diseases (hypertension, diabetes mellitus, dementia, Parkinson's disease, Down's syndrome, stroke) was also elicited. Ages of father and mother at birth were also recorded. Chi-square test, Kruskal-Wallis analysis of variance, cluster analysis, and logistic regression analysis were used for statistical analysis. The results (chi-square test) showed a statistically significant difference between patients with dementia of the Alzheimer type and controls as far as marital status (p = .04), the subject's history of major depressive episode (p = .02), and family history of dementia (p = .002) were concerned. Logistic regression analysis results produced a complex model of family aggregation of dementia, with patients with a history of depression and family history of dementia having an up to seven times higher risk of developing AD. These findings, especially a family history of dementia, are consistent with most of the literature.     

Risk factors for familial and sporadic ovarian cancer among French Canadians: a case-control study

OBJECTIVE: The objective was to compare risk factors between familial and sporadic ovarian cancer by means of a case-control approach. STUDY DESIGN: We conducted a case-control study among French Canadian women in Montreal during 1995-1996. One hundred seventy women 20 to 84 years old with histologically confirmed diagnoses of primary ovarian carcinomas or borderline tumors were interviewed concerning their reproductive, family, and medical histories. During the same period 170 randomly selected population control subjects, frequency-matched to the case patients according to age and ethnic group, were also interviewed. Unconditional logistic regression methods were used for data analysis. RESULTS: The major factors influencing the risk of development of ovarian cancer were as follows: (1) family history of breast or ovarian cancer, (2) a late age at use of oral contraceptives (a protective effect), and (3) a late age at last childbirth (a protective effect for familial case patients only). CONCLUSION: These factors had equally great impacts in familial and sporadic cases, implying that the underlying mechanisms of carcinogenesis in sporadic and familial ovarian cancer may be similar and that hereditary ovarian cancer may be preventable.     

Clinical factors associated with pain in acute myocardial infarction

In an unselected population of 921 consecutive patients with acute myocardial infarction admitted to one single hospital, regardless of age and whether they were admitted to the coronary care unit or not, we describe the course of pain during hospitalization. Patients with a history of angina pectoris, patients with a particularly long delay time, and patients not transported by ambulance had the longest duration of pain.     

Risk stratifying patients who survive an acute myocardial infarction

While androgens have important skeletal effects, the mechanism(s) of androgen action on bone remain unclear. Current osteoblast models to study androgen effects have several limitations, including the presence of heterogeneous cell populations. In this study, we examined the effects of androgens on the proliferation and differentiation of a novel human fetal osteoblastic cell line (hFOB/AR-6) that expresses a mature osteoblast phenotype and a physiological number (approximately 4,000/nucleus) of androgen receptors (AR). Treatment with 5alpha-dihydrotestosterone (5alpha-DHT) inhibited the proliferation of hFOB/AR-6 cells in a dose-dependent fashion, while it had no effect on the proliferation of hFOB cells, which express low levels of AR (<200/nucleus). In hFOB/AR-6 cells, co-treatment with the specific AR antagonist, hydroxyflutamide abolished 5alpha-DHT-induced growth inhibition. Steady-state levels of transforming growth factor-beta1 (TGF-beta1) and TGF-beta-induced early gene (TIEG) mRNA decreased after treatment of hFOB/AR-6 cells with 5alpha-DHT, suggesting a role for the TGF-beta1-TIEG pathway in mediating 5alpha-DHT-induced growth inhibition of hFOB/AR-6 cells. In support of this, co-treatment of hFOB/AR-6 cells with TGF-beta1 (40 pg/ml) reversed the 5alpha-DHT-induced growth inhibition, whereas TGF-beta1 alone at this dose had no effect on hFOB/AR-6 cell proliferation. Furthermore, treatment of hFOB/AR-6 cells with 5alpha-DHT and testosterone (10(-8) M) inhibited basal and 1,25-(OH)2D3-induced alkaline phosphatase (ALP) activity and type I collagen synthesis without affecting osteocalcin production. Thus, in this fetal osteoblast cell line expressing a physiological number of AR, androgens decrease proliferation and the expression of markers associated with osteoblast differentiation. These studies suggest that the potential anabolic effect of androgens on bone may not be mediated at the level of the mature osteoblast.     

Plasma Lp(a), apolipoprotein(a) isoforms and acute myocardial infarction in men and women: a case-control study in the Jerusalem population

The relationship of Lp(a) with manifestations of coronary heart disease (CHD) has not been studied extensively in women. There is little information as to the association of the unique Lp(a) apolipoprotein moiety (apo(a)) with CHD in either men or women. We therefore assessed the association of the apo(a) polymorphism and of Lp(a) with first acute myocardial infarction (MI) in a population-based case-control study in Jewish residents of Jerusalem between the ages of 25 and 64. The patients consisted of 238 men and 47 women hospitalized for a first acute MI in the 4 hospitals of Jerusalem serving the population (70% response rate among all first MI patients). The control subjects comprised 318 men and 159 women sampled from the national population registry and who were free of CHD (75% response). Lp(a) and apo(a) were measured in plasma stored at -20 degrees C for 6-24 months. Among men, plasma Lp(a) concentrations were higher in cases than controls in both univariate and multivariate analyses. The elevated risk was limited to the upper fifth of the Lp(a) distribution (unadjusted odds ratio = 1.65, P < 0.01 vs. the lower four quintiles, multivariable odds ratio = 1.82, P < 0.01). Among women, Lp(a) was not elevated in acute MI patients. Apo(a) isoforms with a B, S1 or S2 band (associated with higher Lp(a) values and having lower molecular weights) were more prevalent in female MI cases than controls (unadjusted odds ratio = 2.5, P = 0.016). This association could not be attributed to the higher Lp(a) concentrations associated with these isoforms and was not seen in men. In conclusion, our study points to an association of the apo(a) isoforms with acute MI in women, not evident in this population sample in men. Previously described associations of elevated Lp(a) with acute MI were confirmed in men but not in women. While the role of chance and inadequate statistical power cannot be excluded, the suggestion of a sex difference in the strength of these associations deserves further investigation, as does the question of whether apo(a) phenotype contributes to risk independently of Lp(a) level.     

Thrombolysis for acute myocardial infarction

Thrombolytic therapy has been a major advance in the management of acute myocardial infarction. Unfortunately, it continues to be underused or is administered later than is optimal. Thrombolytic therapy works by lysing infarct artery thrombi and achieving reperfusion, thereby reducing infarct size, preserving left ventricular function, and improving survival. The most effective thrombolytic regimens achieve angiographic epicardial infarct-artery patency in only approximately 50% of patients within 90 minutes. Bleeding requiring transfusion occurs in approximately 5% of patients and stroke in approximately 1.8% with these regimens, which include adjunctive aspirin and intravenous heparin. There are several ways in which reperfusion rates and thus patient outcomes might be improved, such as different dosing regimens of established agents; combinations of different agents; improved adjunctive therapy such as direct antithrombin agents, low-molecular-weight heparin, or glycoprotein IIb/IIIa receptor antagonists; or the development of novel thrombolytic agents with enhanced fibrin specificity, resistance to native inhibitors, or prolonged half-lives allowing bolus administration. All of these strategies are being tested in clinical trials. The best approach currently is to administer thrombolytic therapy as soon as possible to all patients without contraindications who present within 12 hours of symptom onset and have ST-segment elevation on the ECG or new-onset left bundle-branch block, unless an alternative reperfusion strategy is planned.     

Risk stratification after acute myocardial infarction: which studies are best?

The prognosis for a patient who has survived an acute myocardial infarction depends on three general prognostic factors: (1) residual left ventricular function, (2) remaining viable myocardium at risk (residual ischemia), and (3) presence of substrate for the development of malignant arrhythmias. Multiple clinical and historical factors predict the presence of one or more of these prognostic indicators. Electrocardiographic exercise treadmill testing needs to be done in all patients with uncomplicated infarctions. Guidelines of the American College of Cardiology/American Heart Association Task Force are recommended for risk stratification in most patients after acute myocardial infarction.     

Risk factors for Trypanosoma cruzi infection among children in central Brazil: a case-control study in vector control settings

This population-based case-control study was conducted in northern Goias State, central Brazil, in rural settings under vector control surveillance. One hundred forty-nine children seropositive for Trypanosoma cruzi antibodies, selected in a cross-sectional survey carried out in village schools, were compared with 298 seronegative classmate controls matched for age, sex, and place of residence. Information on potential environmental, familiar, and social economic risk factors for T. cruzi infection was collected during household visits, and interviews with parents and entomologic inspections of domestic and peridomestic environments were conducted. The presence of triatomines in dwellings or evidence of triatomine colonization was found to be statistically associated with seropositivity in children. The presence of exuviae and a report of triatomines indoors or outdoors by householders in the past were strong predictors of an infected child. Children from seropositive mothers had a 3.9-fold increase in the risk of having anti-T. cruzi antibodies after adjusting for the confounding variables, including triatomine capture, mother's age, and family size in multivariate analysis. Parent's report of vector presence showed a 97.7% sensitivity in identifying a dwelling with at least one seropositive child. The possibility of transplacental T. cruzi transmission and its implication for Chagas' disease control were considered.