| 1. |
- Andersson, Eva M., 1968, et al.
(författare)
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Predictions by early indicators of the time and height of the peaks of yearly influenza outbreaks in Sweden
- 2008
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Ingår i: Scandinavian Journal of Public Health. - : SAGE Publications. - 1403-4948 .- 1651-1905. ; 36:5, s. 475-482
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Methods for prediction of the peak of the influenza from early observations are suggested. These predictions can be used for planning purposes. Methods: In this study, new robust methods are described and applied to weekly Swedish data on influenza-like illness (ILI) and weekly laboratory diagnoses of influenza (LDI). Both simple and advanced rules for how to predict the time and height of the peak of LDI are suggested. The predictions are made using covariates calculated from data in early LDI reports. The simple rules are based on the observed LDI values, while the advanced ones are based on smoothing by unimodal regression. The suggested predictors were evaluated by cross-validation and by application to the observed seasons. Results: The relationship between ILI and LDI was investigated, and it was found that the ILI variable is not a good proxy for the LDI variable. The advanced prediction rule regarding the time of the peak of LDI had a median error of 0.9 weeks, and the advanced prediction rule for the height of the peak had a median deviation of 28%. Conclusions: The statistical methods for predictions have practical usefulness.
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| 2. |
- Andersson, Eva M., 1968, et al.
(författare)
-
Predictions by early indicators of the time and height of yearly influenza outbreaks in Sweden
- 2007
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Aims: Methods for prediction of the peak of the influenza from early observations are suggested. These predictions can be used for planning purposes. Methods: In this study, new robust methods are described and applied on weekly Swedish data on influenza-like illness (ILI) and weekly laboratory diagnoses of influenza (LDI). Both simple and advanced rules for how to predict the time and height of the peak of LDI are suggested. The predictions are made using covariates calculated from data in early LDI reports. The simple rules are based on the observed LDI values while the advanced ones are based on smoothing by unimodal regression. The suggested predictors were evaluated by cross-validation and by application to the observed seasons. Results: The relation between ILI and LDI was investigated and it was found that the ILI variable is not a good proxy for the LDI variable. The advanced prediction rule regarding the time of the peak of LDI had a median error of 0.9 weeks, and the advanced prediction rule for the height of the peak had a median deviation of 28%. Conclusions: The statistical methods for predictions have practical usefulness.
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| 3. |
- Eriksson, Helena, 1971, et al.
(författare)
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Longitudinal study of occupational noise exposure and joint effects with job strain and risk for coronary heart disease and stroke in Swedish men.
- 2018
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Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 8:4
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Tidskriftsartikel (refereegranskat)abstract
- The aims were to investigate whether occupational noise increased the risk for coronary heart disease (CHD) and stroke and to elucidate interactions with stressful working conditions in a cohort of Swedish men.This is a prospective cohort study on CHD and stroke in Swedish men followed until death, hospital discharge or until 75 years of age, using Swedish national registers on cause of death and hospital discharges. Baseline data on occupation from 1974 to 1977 were used for classification of levels of occupational noise and job demand-control. Cox regression was used to analyse HRs for CHD and stroke.Swedish men born in 1915-1925.CHD and stroke.The participants of the study were men from the Primary Prevention Study, a random sample of 10 000 men born in 1915-1925 in Gothenburg. Subjects with CHD or stroke at baseline or were not employed were excluded. The remaining subjects with complete baseline data on occupation, weight, height, hypertension, diabetes, serum cholesterol and smoking constituted the study sample (5753 men).There was an increased risk for CHD in relation to noise levels 75-85 dB(A) and >85dB(A) compared with <75dB(A) (HR 1.15, 95% CI 1.01 to 1.31, and HR 1.27, 95% CI 0.99 to 1.63, respectively). Exposure to noise peaks also increased the risk for CHD (HR 1.19, 95%CI 1.03 to 1.38). Among those with high strain (high demands and low control) combined with noise >75dB(A), the risk for CHD further increased (HR 1.80, 95% CI 1.19 to 2.73). There was no significantly increased risk for stroke in any noise category.Exposure to occupational noise was associated with an increased risk for CHD and the risk further increased among those with concomitant exposure to high strain. None of the analysed variables were related to increased risk for stroke.
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| 4. |
- Frisén, Marianne, 1943, et al.
(författare)
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Evaluation of multivariate surveillance
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Multivariate surveillance is of interest in many areas such as industrial production, bioterrorism detection, spatial surveillance, and financial transaction strategies. Some of the suggested approaches to multivariate surveillance have been multivariate counterparts to the univariate Shewhart, EWMA, and CUSUM methods. Our emphasis is on the special challenges of evaluating multivariate surveillance methods. Some new measures are suggested and the properties of several measures are demonstrated by applications to various situations. It is demonstrated that zero-state and steady-state ARL, which are widely used in univariate surveillance, should be used with care in multivariate surveillance.
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| 5. |
- Frisén, Marianne, 1943, et al.
(författare)
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Evaluation of Multivariate Surveillance
- 2010
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Ingår i: Journal of Applied Statistics. - : Informa UK Limited. - 0266-4763 .- 1360-0532. ; 37:12, s. 2089-2100
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Tidskriftsartikel (refereegranskat)abstract
- Multivariate surveillance is of interest in many areas such as industrial production, bioterrorism detection, spatial surveillance, and financial transaction strategies. Some of the suggested approaches to multivariate surveillance have been multivariate counterparts to the univariate Shewhart, EWMA, and CUSUM methods. Our emphasis is on the special challenges of evaluating multivariate surveillance methods. Some new measures are suggested and the properties of several measures are demonstrated by applications to various situations. It is demonstrated that zero-state and steady-state ARL, which are widely used in univariate surveillance, should be used with care in multivariate surveillance.
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| 6. |
- Frisén, Marianne, 1943, et al.
(författare)
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MULTIVARIATE CONTROL CHARTS FOR SURVEILLANCE OF OUTBREAKS
- 2009
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Ingår i: International Conference on Frontiers of Interface between Statistics and Sciences 30 Dec 2009-2 Jan 2010, Hyderabad, India.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 7. |
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| 8. |
- Frisén, Marianne, 1943, et al.
(författare)
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Robust outbreak surveillance of epidemics in Sweden
- 2009
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Ingår i: Statistics in Medicine. - : Wiley. - 0277-6715. ; 28:3, s. 476-493
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Tidskriftsartikel (refereegranskat)abstract
- Outbreak detection is of interest in connection with several diseases and syndromes. The aim is to detect the progressive increase in the incidence as soon as possible after the onset of the outbreak. A semiparametric method is applied to Swedish data on tularaemia and influenza. The method is constructed to detect a change from a constant level to a monotonically increasing incidence. If seasonal effects are present, the residuals from a model incorporating these can be used. The properties of the method are evaluated by application to Swedish data on tularaemia and influenza and by simulations. The suggested method is compared with subjective judgments as well as with other algorithms. The conclusion is that the method works well. A user-friendly computer program is described.
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| 9. |
- Frisén, Marianne, 1943, et al.
(författare)
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Sufficient reduction in multivariate surveillance
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The relation between change points in multivariate surveillance is important but seldom considered. The sufficiency principle is here used to clarify the structure of some problems, to find efficient methods, and to determine appropriate evaluation metrics. We study processes where the changes occur simultaneously or with known time lags. The surveillance of spatial data is one example where known time lags can be of interest. A general version of a theorem for the sufficient reduction of processes that change with known time lags is given. A simulation study illustrates the benefits or the methods based on the sufficient statistics.
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| 10. |
- Frisén, Marianne, 1943, et al.
(författare)
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Sufficient reduction in multivariate surveillance
- 2011
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Ingår i: Communication in Statistics. Theory and Methods. - : Informa UK Limited. - 0361-0926 .- 1532-415X. ; 40:10, s. 1821-1838
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Tidskriftsartikel (refereegranskat)abstract
- The relation between change points in multivariate surveillance is important but seldom considered. The sufficiency principle is here used to clarify the structure of some problems, to find efficient methods, and to determine appropriate evaluation metrics. We study processes where the changes occur simultaneously or with known time lags. The surveillance of spatial data is one example where known time lags can be of interest. A general version of a theorem for the sufficient reduction of processes that change with known time lags is given. A simulation study illustrates the benefits or the methods based on the sufficient statistics.
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