BACKGROUND: If several risk factors for disease are considered in a regression model and these factors are affected by measurement errors, the observed relative risk will be attenuated. In nutritional epidemiology, several nutrient variables show strong correlation, described as collinearity. The observed relative risk will then depend not only on the validity of the chosen diet assessment method but also on collinearity between variables in the model. METHODS: The validity of different diet assessment methods are compared. The correlation coefficients between common nutrients and foods are given using data from the Malm? Food Study. Intake of nutrients and foods were assessed with a modified diet history method, combining a 2-week food record for beverages and lunch/dinner meals and a food frequency questionnaire for other foods. The study population comprised 165 men and women aged 50-65 years. A multivariate logistic regression model is used to illustrate the effect of collinearity on observed relative risk (RRo). RESULTS: A moderate to high correlation between risk factors will substantially influence RRo even when using diet assessment methods with high validity. Methods with low validity might even give inverse RRo. CONCLUSION: It is stressed that caution must be exercised and only a selected number of variables should be included in the model, especially when they are highly intercorrelated, since RRo might be severely biased.
There is some evidence that birth weight is associated with breast cancer. Whether this association differs between premenopausal and postmenopausal ages is still unclear. The results from this study suggest that higher birth weight is a risk factor for postmenopausal breast cancer (OR 1.06, CI 1.00-1.12, per 100 g), independent of selected early-life and adult factors.
A circadian variation of symptom onset in acute myocardial infarction (AMI) with an increased frequency in the late morning and possibly also in the evening has been found in several studies. It has been suggested that different circadian rhythms may exist in various subgroups of patients. This possibility was examined in a population of 10,791 patients collected between 1973 and 1987 in a continuously operating register of patients with AMI in Malmö, Sweden. In 6,763 patients (63%) in whom a distinct symptom onset could be established, symptom onset occurred with an increased frequency between 6:01 A.M. and 12:00 noon (30.6%) and between 6:01 P.M. and 12:00 midnight (26.9%). Similar bimodal circadian rhythms were seen in patients aged greater than 70 years (n = 2,923), less than or equal to 70 years (n = 3,840), men (n = 4,528), women (n = 2,235), smokers (n = 2,458), hypertensives (n = 1,999), diabetics (n = 653), patients with (n = 1,872) and without (n = 4,891) a history of previous AMI, and in patients with recent non-Q-wave AMI (n = 333). In 455 patients receiving cardioselective beta blockers the circadian distribution did not differ from a random, whereas in patients taking nonselective beta blockers or calcium antagonists significant bimodal rhythms were found. Statistically significant interactions were found between symptom onset and age dichotomized at 70 years, and between patients with and without a history of previous AMI. In a multivariate analysis only these variables age less than or equal to/greater than 70 years; +/- history of a previous AMI) were found to modify the circadian rhythm of symptom onset in the population.(ABSTRACT TRUNCATED AT 250 WORDS)
To assess the effects of current treatments with beta-blockers or calcium antagonists on the clinical outcome of acute myocardial infarction (MI), enzymatically estimated infarct sizes, circulatory arrests from ventricular tachyarrhythmias, ventricular tachycardia (VT)/ventricular fibrillation (VF), and in-hospital mortality were analyzed retrospectively from 7,922 citizens of Malmö, Sweden, hospitalized due to a first MI between 1973 and 1987. Of these patients, 296 were on treatment with calcium antagonists, 393 on treatment with a beta 1-selective beta-blocker, 482 with a nonselective beta-blocker, and 95 on combined treatment with beta-blockers and calcium antagonists at the time of admission to hospital. In a set of multivariate analyses including several clinical characteristics, patients on treatment with a nonselective beta-blocker had a significantly lower peak aspartate aminotransferase (ASAT; difference -0.70 mukat/l, 95% CL: -1.24 to -0.16), whereas no significant relations between peak ASAT and treatment with cardioselective beta-blockers or calcium antagonists were found. Treatment with cardioselective beta-blockers or calcium antagonists, in contrast to treatment with a nonselective beta-blocker, were significant predictors of the occurrence of circulatory arrests from VT/VF. The relative risk of VT/VF in patients on cardioselective beta-blockers was 1.51 (95% CI: 1.12-2.03), and in patients on calcium antagonists 1.44 (95% CI: 1.03-2.02). None of the treatments were significantly associated with in-hospital mortality. In patients on beta-blockers or calcium antagonists when suffering their first MI, nonselective beta-blockade may reduce infarct size. Treatment with beta-blockers or calcium antagonists identified patients with an increased risk of circulatory arrests from VT/VF, but neither of the treatments were significantly associated with in-hospital mortality. We suggest that only minor differences exist between the effects of chronic treatment with beta-blockers and calcium antagonists on the outcome of an acute MI.
OBJECTIVES: To explore the development of hypertension (HT) in a cohort of young middle-aged men. DESIGN: Prospective birth-cohort study of men surveyed over 6 years. SETTING: Helsingborg County Hospital, Sweden, 1990-97. SUBJECTS: A total of 628 men born in 1953-54, all surveyed at 37, 40 and 43 years of age. MAIN OUTCOME MEASURES: Systolic blood pressure (SBP), diastolic blood pressure (DBP), S-cholesterol, body mass index (BMI), alcohol consumption, ethnicity. HT was defined as SBP > or = 140 mmHg and/or DBP > or = 90 mmHg, or ongoing treatment. Using SBP
The objective was to examine relationships between meat and other food items which have been associated with higher risk of cancer in the colon and prostate in some epidemiological studies. The study was conducted as a population-based cohort study comprising 11648 subjects (4816 male and 6742 female) born between 1926 and 1945 and living in the city of Malmö, Sweden. Data on mean daily intake of foods and nutrients were assessed with a diet history method combining a 7-day menu book and a food frequency questionnaire. Increasing meat intake, expressed in quintiles and adjusted for energy, was associated with decreasing intakes of poultry, fish, fruits, bread, cereals and cheese in both sexes. Low negative correlations between meat intake and ascorbic acid (r= -0.11) and fiber (r= -0.16 to -0.20) were noted. The average intake of fat from meat out of total fat intake was 13.6% in men and 11.9% in women. No major associations were noted between meat and the cholesterol raising fatty acids C:12:0, C:14:0, C:160 nor for C:20:4 or its precursor C:18:2. In conclusion, our findings indicate that meat consumption is negatively associated with food groups rich in antioxidants and fiber and the positive covariance reported between meat and cancer and coronary heart disease might, therefore, not be directly linked to components in meat.
OBJECTIVE: Comparative data on ecological differences in body fatness and fat distribution within Europe are sparse. Migration studies may provide information on the impact of environmental factors on body size in different populations. The objective was to investigate differences in adiposity between European immigrants and native Swedes, specifically to examine gender differences and the effect of time since immigration, and to compare two selected immigrant groups with their native countrymen. RESEARCH METHODS AND PROCEDURES: A cross-sectional analysis of 27,808 adults aged 45 to 73 years participating in the Malmö Diet and Cancer prospective cohort study in Sweden was performed. Percentage body fat (impedance analysis) and waist-hip ratio (WHR) were compared between Swedish-born and foreign-born participants. RESULTS: Obesity was 40% more prevalent in non-Swedish Europeans compared with Swedes. Controlling for age, height, smoking, physical activity, and occupation, it was found that women born in the former Yugoslavia, southern Europe, Hungary, and Finland had a significantly higher percentage of body fat, and those from Hungary, Poland, and Germany had more centralized adiposity compared with Swedish women. Men born in the former Yugoslavia, Hungary, and Denmark had a significantly higher mean percentage of body fat compared with Swedish-born men, whereas Yugoslavian, Finnish, and German men differed significantly in mean WHR. Length of residence in Sweden was inversely associated with central adiposity in immigrants. A comparison between German and Danish immigrants, their respective native populations, and Swedes indicated an intermediate positioning of German immigrants with regard to body mass index and WHR. DISCUSSION: Differences in general and central adiposity by country of origin appear to remain after migration. Central adiposity seems to be more influenced than fatness per se by time of residency in Sweden.
From all soft-tissue malignancies reported to the Swedish National Cancer Registry in Southern Sweden (1.3 mill. inhabitants) from 1964 through 1978, 278 cases were accepted as sarcomas after histologic re-examination. All these were malignancy-graded on a four-grade scale, without knowledge of the clinical course. A number of clinical and morphological variables were recorded and subjected to uni-, bi- and multi-variate analysis. Follow-up was available in all patients. The annual incidence rate over all ages was 1.4/100,000. The mean age was 58 years and males dominated (1.3/1). Malignant fibrous histiocytoma, liposarcoma and leiomyosarcoma were the most common histologic groups. Three-fourths of the tumors were high-grade malignant (Grade III-IV). Sixty per cent were deep-seated, having a median size of 8 cm compared to 4 cm for the superficial tumors. One third of all tumors were located in the thigh. The histologic groups were characterized by age, tumor depth and size, the occurrence of pain, malignancy grade and five-year survival; it was seen that each group, with respect to at least one of the variables, differed significantly from all the other groups. Thus histologic classification seems to identify different tumor entities. Out of several pair-wise associations the strongest were as follows: histologic groups versus depth, size, malignancy grade and age; depth versus size; and size versus malignancy grade (Grade IV tumors being larger). The proportion of superficial and small tumors in this series is high, compared to several reported series, probably owing to "referral selection" in the previous studies. The inter-relationships found between several variables and conclusions based on selected series may explain, in part, the differing opinions which can be found in the literature regarding prognostic variables in soft-tissue sarcoma.
This study examined the relations between food patterns and five components of the metabolic syndrome in a sample of Swedish men (n = 2,040) and women (n = 2,959) aged 45-68 years who joined the Malmö Diet and Cancer study from November 1991 to February 1994. Baseline examinations included an interview-administered diet history, a self-administered questionnaire, blood pressure and anthropologic measurements, and blood samples donated after an overnight fast. Cluster analysis identified six food patterns for which 43 food group variables were used. Logistic regression analysis was used to examine the risk of each component (hyperinsulinemia, hyperglycemia, hypertension, dyslipidemia, and central obesity) and food patterns, controlling for potential confounders. The study demonstrated relations, independent of specific nutrients, between food patterns and hyperglycemia and central obesity in men and hyperinsulinemia in women. Food patterns dominated by fiber bread provided favorable effects, while food patterns high in refined bread or in cheese, cake, and alcoholic beverages contributed adverse effects. In women, food patterns dominated by milk-fat-based spread showed protective relations with hyperinsulinemia. Relations between risk factors and food patterns may partly depend on gender differences in metabolism or food consumption and on variations in confounders across food patterns.