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- Adami, HO, et al.
(författare)
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Epidemiology, medicine and public health
- 1999
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Ingår i: International journal of epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 28:5, s. S1005-S1008
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Tidskriftsartikel (refereegranskat)
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- Cutts, F T, et al.
(författare)
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Child and Maternal Mortality during a Period of Conflict in Beira City, Mozambique
- 1996
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Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 25:2, s. 349-356
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Tidskriftsartikel (refereegranskat)abstract
- Background Child mortality rates have been declining in most developing countries. We studied child and maternal mortality and risk factors for child mortality in Beira city in July 1993, after a decade of conflict in Mozambique. Methods A community-based cluster sample survey of 4609 women of childbearing age was conducted. Indirect techniques were used to estimate child mortality (‘children ever born’ method and Preceding Birth Techniques [PBT]), and maternal mortality sisterhood method). Deaths among the most recent born child, born since July 1990, were classified as cases (n = 106), and two controls, matched by age and cluster, were selected per case. Results Indirect estimates of the probability of dying from birth to age 5 (deaths before age 5 years, 5q0 per 1000) decreased from 246 in 1977/8 to 212 in 1988/9. The PBT estimate for 1990/91 was 154 (95% confidence interval(CI): 124–184), but recent deaths may have been underreported. Lack of beds in the household (odds ratio[OR] = 2.0, 95% CI: 1.1–3.8), absence of the father (OR = 2.4, 95% CI: 1.2–4.8), low paternal educational level (OR = 2.1, 95% CI: 0.8–5.4), young maternal age (OR = 2.0, 95% CI: 1.0–3.7), self-reported maternal illness (OR = 2.4, 95% CI: 1.2–4.9), and home delivery of the child (OR = 2.3, 95% CI: 1.2–4.5) were associated with increased mortality, but the sensitivity of risk factors was low. Estimated maternal mortality was 410/100 000 live births with a reference date of 1982. Conclusions Child mortality decreased slowly over the 1980s in Beira despite poor living conditions caused by the indirect effects of the war. Coverage of health services increased over this period. The appropriateness of a risk approach to maternal-child-health care needs further evaluation.
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- Diderichsen, F, et al.
(författare)
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Trends in occupational mortality among middle-aged men in Sweden 1961-1990.
- 1997
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Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 26:4, s. 782-7
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Many European countries have in recent decades reported growing socioeconomic differentials in mortality. While these trends have usually paralleled high unemployment and increasing income disparities, Sweden had low unemployment and narrowing income differences. This study describes trends, 1961-1990, in total and cardiovascular mortality among men, 45-69 years of age, in major occupational classes in Sweden. METHODS: From census data four cohorts were created from those enumerated in 1960, 1970, 1980 and 1985. Through record linkage with the Swedish cause of death registry the mortality in each cohort was followed for 5-10 years. Age-standardized mortality trends 1961-1990 were calculated for occupational groups, categorized according to sector of the economy. RESULTS: The increase in mortality among middle-aged men in Sweden 1965-1980 was mainly a result of increasing cardiovascular mortality among industrial workers and farmers. In the 1980s the trend for these groups changed into a last decrease in mortality similar to that for non-manual occupations for the whole period. Consequently the rate ratio for industrial workers in comparison with men having a professional/managerial type of occupation increased from 0.98 to 1.43. The slowest decrease is now found among unqualified occupations in services and transportation. CONCLUSIONS: While Sweden, during the period studied, had narrowing income differentials and low unemployment this result points to the importance of working conditions in understanding trends and distribution of male adult mortality.
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- Elmståhl, Sölve, et al.
(författare)
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Bias in diet assessment methods - Consequences of collinearity and measurement errors on power and observed relative risks
- 1997
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Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 26:5, s. 1071-1079
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Tidskriftsartikel (refereegranskat)abstract
- 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 Malmo 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.
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- Forsberg, Bertil, et al.
(författare)
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Childhood asthma in four regions in Scandinavia : risk factors and avoidance effects
- 1997
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Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 26:3, s. 610-619
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The high and increasing prevalence of childhood asthma is a major public health issue. Various risk factors have been proposed in local studies with different designs.METHODS: We have made a questionnaire study of the prevalence of childhood asthma, potential risk factors and their relations in four regions in Scandinavia (Umeå and Malmö in Sweden, Kuopio in eastern Finland and Oslo, Norway). One urban and one less urbanized area were selected in each region, and a study group of 15962 children aged 6-12 years was recruited.RESULTS: The prevalence of symptoms suggestive of asthma varied considerably between different areas (dry cough 8-19%, asthma attacks 4-8%, physician-diagnosed asthma 4-9%), as did the potential risk factors. Urban residency was generally not a risk factor. However, dry cough was common in the most traffic polluted area. Exposure to some of the risk factors. such as smoking indoors and moisture stains or moulds at home during the first 2 years of life, resulted in an increased risk. However, current exposure was associated with odds ratios less than one.CONCLUSIONS: Our findings were probably due to a combination of early impact and later avoidance of these risk factors. The effects of some risk factors were found to differ significantly between regions. No overall pattern between air pollution and asthma was seen, but air pollution differed less than expected between the areas.
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- Hallqvist, Johan, 1950-, et al.
(författare)
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Socioeconomic differences in risk of myocardial infarction 1971-1994 in Sweden : time trends, relative risks and population attributable risks.
- 1998
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Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 27:3, s. 410-5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The general trend in incidence of myocardial infarction (MI) in the Stockholm area changed from increasing to decreasing around 1980. The objective of this study is to examine time trends in incidence in major socioeconomic strata, relative risk between socioeconomic groups and population risk attributable to socioeconomic differences during this period. METHODS: All cases of MI from 1971 to 1986 were identified from hospital discharge and cause-of-death registers. Person-years for each year of follow-up were calculated from the population register in the Stockholm region 1971-1986. Census registers were used for information on socioeconomic status. Register information was individually linked through the Swedish personal identification number. Supplementary information for 1992-1994 was taken from the case-control study SHEEP (Stockholm Heart Epidemiology Program). RESULTS: The decline in MI risk among male high- and middle-level employees started in 1976 and in male manual workers in 1981. For women incidence increased from 1971 to 1986 among manual workers and decreased among high- and middle-level employees. The increase over time of the relative risk from low socioeconomic position continued into the 1990s. Despite the reduction of the category of manual workers, the population attributable risk from socioeconomic differences also increased over time. The process of social change influencing the size of the socioeconomic groups contributes to the change in time trends of MI morbidity. CONCLUSIONS: The increase over time of relative and population attributable risks of MI from low socioeconomic status add to the public health importance of social inequity.
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- Holmberg, Lars, et al.
(författare)
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A search for recall bias in a case-control study of diet and breast cancer
- 1996
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Ingår i: International Journal of Epidemiology. - 0300-5771 .- 1464-3685. ; 25:2, s. 235-244
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND. In retrospective studies of dietary habits and breast cancer risk, recall bias is a concern since diet has been publicized as a cause of breast cancer. METHODS. In a case-control study of diet and breast cancer risk nested within a cohort of women screened with mammography, we contrasted answers to a retrospective dietary interview with answers to a dietary questionnaire which was filled out before any diagnostic procedures for breast cancer were undertaken. The source population was all women aged 40-74 in two counties in Sweden invited to mammographic screening and asked to fill out a questionnaire before the screening. Cases and controls were subsequently defined -- matched on age, county of residence, and time of mammography -- and approached for an interview. RESULTS. In all, 265 cases and 431 controls participated in the study. Means of frequencies differed between the agreement in the questionnaire's and the interview's classifications of study subjects into quartiles of monthly intake varied between 31 percent and 57 percent. Kappa statistics in all food groups were below 0.41. In a regression analysis, case subjects with low responses on the questionnaire about intake of meat, snacks, and coffee and tea gave higher responses on interview than did controls who had low questionnaire responses for these food groups. The reverse was also true: cases' responses that were high on the questionnaire were lower on interview for these food groups than were controls' responses. CONCLUSIONS. We found few signs of recall bias, and the few indications of a differential misclassification that we found were not in food groups that have been publicly discussed as causes of breast cancer.
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- Michaëlsson, Karl, et al.
(författare)
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Diet and Hip Fracture Risk - A Case-control Study : Study Group of the Multiple Risk Survey on Swedish Women for Eating Assessment
- 1995
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Ingår i: International Journal of Epidemiology. - 0300-5771 .- 1464-3685. ; 24:4, s. 771-782
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- BACKGROUND. The role of diet as a risk factor for osteoporotic fractures is unclear. Earlier studies have yielded conflicting results. METHODS. In two counties in central Sweden we investigated the association between dietary intake and the risk of proximal femoral fractures in a case-control study nested in a cohort. Women born in 1914-1948 were asked to fill out a food frequency questionnaire when invited to attend for mammographic screening between the years 1987 and 1990. More than 65,000 women completed the questionnaire. Those who had participated in the enquiry and subsequently sustained a first hip fracture were defined as cases. For every case, four individually matched controls, by age and county of residence, were selected from the cohort. A second questionnaire concerning confounding factors was mailed to controls and cases. In all, 247 cases and 893 controls could finally be included. Monthly intake of foods and daily intake of nutrients were calculated. RESULTS. When highest quartile of intake was compared to lowest, intakes of iron (adjusted odds ratio [OR] of 3.3, 95% confidence interval [CI]: 1.6-6.9), magnesium (adjusted OR = 2.7, 95% CI: 1.3-6.0) and vitamin C (adjusted OR = 1.9, 95% CI: 1.2-3.1) were found to be independent risk factors for hip fracture. High calcium intake did not protect against hip fracture. Smoking, low physical activity in leisure time, low body mass index, earlier fracture of the distal forearm and diabetes were all risk factors while postmenopausal hormone replacement therapy protected against hip fracture. DISCUSSION. This large study indicates new dietary risk factors for hip fracture. The association between high dietary intake of iron, magnesium and vitamin C and risk of hip fracture has not been reported previously. Further clinical and experimental studies are needed to confirm these findings and to investigate their mechanism of action.
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- Michaëlsson, Karl, 1959-, et al.
(författare)
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Effect of prefracture versus postfracture dietary assessment on hip fracture risk estimates
- 1996
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Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 25:2, s. 403-10
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND. Dietary factors are presumed to have influence on bone mass and hence fracture susceptibility. Most information in this respect is based on retrospective assessment of previous dietary habits. In a population-based case-control study nested within a cohort, we collected dietary information both before and after a first hip fracture. Thus it was possible to study reported changes in dietary habits, intentional as well as unintentional, among hip fracture patients after a first hip fracture and to compare postfracture with prefracture dietary information. METHODS. More than 65 000 women born 1914-1948 in two counties in central Sweden completed a food frequency questionnaire regarding their usual current dietary habits, before attending a mammographic screening between the years 1987 and 1990. Subsequently 123 of them sustained a first hip fracture and were defined as cases in the present study. For every case, one control, individually matched by age and county of residence, was selected from the cohort. A second identical food frequency questionnaire was mailed to both cases and controls on average 2 years after the hip fracture event. In total 98 case/control pairs could be included in the analysis. The association between diet and hip fracture was evaluated and the results from the two dietary assessments were contrasted. Women who themselves claimed that they had not changed their diet in recent years were analysed separately. RESULTS. The hip fracture cases, compared with the controls, had reduced their reported dietary intake of dairy products after the fracture. Apparently this was not intentional since this effect was more pronounced among those cases who claimed that their diet was unchanged. The changes were most apparent among the younger cases with a more recent hip fracture and with a body mass index above the median. Half of the cases, more than twice the frequency in controls, who were initially classified as having high intake of dairy products were classified as having low intake (<800 mg calcium/day) after the hip fracture. This also lowered, in fact reversed, the relative risk estimates of hip fracture both for intake of dairy products and calcium. Crude odds ratios of highest quartile of intake versus lowest, changed from 3.0 to 0.6 for dairy products and from 2.6 to 0.9 for calcium. No other foods or nutrients displayed such notable differences between the two surveys. CONCLUSION. We conclude that the use of current and retrospective dietary information after a hip fracture can lead to a differential misclassification in dietary studies and to biased estimates of hip fracture risk as compared with prospectively collected dietary information.
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- Mogren, I, et al.
(författare)
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Recurrence of prolonged pregnancy.
- 1999
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Ingår i: International Journal of Epidemiology. - 0300-5771 .- 1464-3685. ; 28:2, s. 253-7
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Tidskriftsartikel (refereegranskat)abstract
- Although moderate, prolonged pregnancy in mother may be a risk factor for prolonged pregnancy in daughter. A previous prolonged pregnancy increases the risk of prolonged pregnancy in a subsequent birth. However, the familial factor of prolonged pregnancy explains just a minor part of its occurrence in the population (due to small population attributable proportions).
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- Månsson, Nils-Ove, et al.
(författare)
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Body mass index and disability pension in middle-aged men--non-linear relations
- 1996
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Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 1464-3685 .- 0300-5771. ; 25:1, s. 80-85
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Obesity has, in a number of studies, been found to correlate to disability and mortality, primarily due to diseases of the circulatory and musculoskeletal systems. In addition, an excess mortality among underweight subjects has been observed in previous studies. METHODS: Five complete birth-year cohorts (1926-1930) of male residents in Malmo (n = 7697) were invited to the survey at the Department of Preventive Medicine, Malmo General Hospital, and 5926 (77%) attended with complete data. Each subject was followed from inclusion, defined by the date of examination, until the end of the calendar year when he turned 58, a total study period of approximately 11 years. Data on about 300 questionnaire items and laboratory tests were determined at the health survey visit. Nationwide Swedish data registers were used for surveillance. RESULTS: Of the participants, 4.7% were underweight, 37.7% overweight, 7.3% obese and 50.3% normal weight; 849 (14.3%) had been granted disability pension at the end of follow-up, 717 after screening. After adjustment for smoking there was a J-shaped relation between body mass index (BMI) and incidence of disability pension, the relative risk ( with the normal group as reference) among underweight men being 1.9. For the overweight subjects it was 1.3 and for the obese 2.8, all differences were significant. Disease of the musculoskeletal and circulatory systems and mental disorders accounted for 67.2% of all main diagnoses resulting in disability pensions during follow-up. A total of 377 (6.4%) men died during follow-up. Diseases of the circulatory system, neoplasms, injury/poisoning and diseases of the respiratory system accounted for 91.8% of the deaths. CONCLUSIONS: Both underweight, overweight and obesity were related to risk of disability pension, with a J-shaped risk relationship.
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