Bakgrunn
- PhD i "Integration of Multivariate Data", Norwegian University of Life Sciences (NMBU)
- MSc i "Bioinformatics", Chalmers University of Technology
- BSc i "Applied Mathematics", K.N.Toosi University of Technology
Arbeidsområder
- Data Science
- Håndtering av BIG DATA
- Rådgiving om databehandling og statistisk analyse
- Data analyse med R og SPSS
Publikasjoner
-
-
Helgeland, Jon; Tomic, Oliver; Hansen, Tonya Moen; Kristoffersen, Doris Tove; Hassani, Sahar & Lindahl, Anne Karin
(2019).
Postoperative wound dehiscence after laparotomy: a useful healthcare quality indicator? A cohort study based on Norwegian hospital administrative data.
BMJ Open.
ISSN 2044-6055.
9(4).
doi:
10.1136/bmjopen-2018-026422.
Fulltekst i vitenarkiv
Vis sammendrag
Objectives Postoperative wound dehiscence (PWD) is
a serious complication to laparotomy, leading to higher
mortality, readmissions and cost. The aims of the present
study are to investigate whether risk adjusted PWD rates
could reliably differentiate between Norwegian hospitals,
and whether PWD rates were associated with hospital
characteristics such as hospital type and laparotomy
volume.
Design Observational study using patient administrative
data from all Norwegian hospitals, obtained from the
Norwegian Patient Registry, for the period 2011–2015, and
linked using the unique person identification number.
Participants All patients undergoing laparotomy, aged at
least 15 years, with length of stay at least 2 days and no
diagnosis code for immunocompromised state or relating
to pregnancy, childbirth and puerperium. The final data
set comprised 66 925 patients with 78 086 laparotomy
episodes from 47 hospitals.
Outcomes The outcome was wound dehiscence,
identified by the presence of a wound reclosure code, risk
adjusted for patient characteristics and operation type.
Results The final data set comprised 1477 wound
dehiscences. Crude PWD rates varied from 0% to 5.1%
among hospitals, with an overall rate of 1.89%. Three
hospitals with statistically significantly higher PWD than
average were identified, after case mix adjustment and
correction for multiple comparisons. Hospital volume was
not associated with PWD rate, except that hospitals with
very few laparotomies had lower PWD rates.
Conclusions Among Norwegian hospitals, there is
considerable variation in PWD rate that cannot be
explained by operation type, age or comorbidity. This
warrants further investigation into possible causes,
such as surgical technique, perioperative procedures
or handling of complications. The risk adjusted PWD
rate after laparotomy is a candidate quality indicator for
Norwegian hospitals.
-
Drange, Ole Kristian; Smeland, Olav Bjerkehagen; Shadrin, Alexey A.; Finseth, Per Ivar; Witoelar, Aree & Frei, Oleksandr
[Vis alle 52 forfattere av denne artikkelen]
(2019).
Genetic Overlap Between Alzheimer’s Disease and Bipolar Disorder Implicates the MARK2 and VAC14 Genes.
Frontiers in Neuroscience.
ISSN 1662-4548.
13.
doi:
10.3389/fnins.2019.00220.
Fulltekst i vitenarkiv
Vis sammendrag
Background: Alzheimer’s disease (AD) and bipolar disorder (BIP) are complex traits influenced by numerous common genetic variants, most of which remain to be detected.
Clinical and epidemiological evidence suggest that AD and BIP are related. However, it is not established if this relation is of genetic origin. Here, we applied statistical methods based on the conditional false discovery rate (FDR) framework to detect genetic overlap between AD and BIP and utilized this overlap to increase the power to identify common genetic variants associated with either or both traits.
Methods: We obtained genome wide association studies data from the International Genomics of Alzheimer’s Project part 1 (17,008 AD cases and 37,154 controls) and
the Psychiatric Genetic Consortium Bipolar Disorder Working Group (20,352 BIP cases and 31,358 controls). We used conditional QQ-plots to assess overlap in common genetic variants between AD and BIP. We exploited the genetic overlap to re-rank test-statistics for AD and BIP and improve detection of genetic variants using the conditional FDR framework.
Results: Conditional QQ-plots demonstrated a polygenic overlap between AD and BIP. Using conditional FDR, we identified one novel genomic locus associated with AD, and
nine novel loci associated with BIP. Further, we identified two novel loci jointly associated with AD and BIP implicating the MARK2 gene (lead SNP rs10792421, conjunctional FDR = 0.030, same direction of effect) and the VAC14 gene (lead SNP rs11649476, conjunctional FDR = 0.022, opposite direction of effect).
Conclusion: We found polygenic overlap between AD and BIP and identified novel loci for each trait and two jointly associated loci. Further studies should examine if the shared loci implicating the MARK2 and VAC14 genes could explain parts of the shared and distinct features of AD and BIP.
-
-
-
Hassani, Sahar; Lindman, Anja Schou; Kristoffersen, Doris Tove; Tomic, Oliver & Helgeland, Jon
(2015).
30-Day Survival Probabilities as a Quality Indicator for Norwegian Hospitals: Data Management and Analysis.
PLOS ONE.
ISSN 1932-6203.
10(9).
doi:
10.1371/journal.pone.0136547.
-
-
Perisic, Nebojsa; Afseth, Nils Kristian; Ofstad, Ragni; Hassani, Sahar & Kohler, Achim
(2013).
Characterising protein, salt and water interactions with combined vibrational spectroscopic techniques.
Food Chemistry.
ISSN 0308-8146.
138(1),
s. 679–686.
doi:
10.1016/j.foodchem.2012.10.117.
-
Ottestad, Inger; Hassani, Sahar; Borge, Grethe iren andersen; Kohler, Achim; Vogt, Kjell gjermund & Hyøtylainen, Tuulia
[Vis alle 11 forfattere av denne artikkelen]
(2012).
Fish oil supplementation alters the plasma lipidomic profile and increases long-chain PUFAs of phospholipids and triglycerides in healthy subjects.
PLOS ONE.
ISSN 1932-6203.
7(8).
doi:
10.1371/journal.pone.0042550.
Fulltekst i vitenarkiv
Vis sammendrag
Background
While beneficial health effects of fish and fish oil consumption are well documented, the incorporation of n-3 polyunsaturated fatty acids in plasma lipid classes is not completely understood. The aim of this study was to investigate the effect of fish oil supplementation on the plasma lipidomic profile in healthy subjects.
Methodology/Principal Findings
In a double-blinded randomized controlled parallel-group study, healthy subjects received capsules containing either 8 g/d of fish oil (FO) (1.6 g/d EPA+DHA) (n = 16) or 8 g/d of high oleic sunflower oil (HOSO) (n = 17) for seven weeks. During the first three weeks of intervention, the subjects completed a fully controlled diet period. BMI and total serum triglycerides, total-, LDL- and HDL-cholesterol were unchanged during the intervention period. Lipidomic analyses were performed using Ultra Performance Liquid Chromatography (UPLC) coupled to electrospray ionization quadrupole time-of-flight mass spectrometry (QTOFMS), where 568 lipids were detected and 260 identified. Both t-tests and Multi-Block Partial Least Square Regression (MBPLSR) analysis were performed for analysing differences between the intervention groups. The intervention groups were well separated by the lipidomic data after three weeks of intervention. Several lipid classes such as phosphatidylcholine, phosphatidylethanolamine, lysophosphatidylcholine, sphingomyelin, phosphatidylserine, phosphatidylglycerol, and triglycerides contributed strongly to this separation. Twenty-three lipids were significantly decreased (FDR<0.05) in the FO group after three weeks compared with the HOSO group, whereas fifty-one were increased including selected phospholipids and triglycerides of long-chain polyunsaturated fatty acids. After seven weeks of intervention the two intervention groups showed similar grouping.
Conclusions/Significance
In healthy subjects, fish oil supplementation alters lipid metabolism and increases the proportion of phospholipids and triglycerides containing long-chain polyunsaturated fatty acids. Whether the beneficial effects of fish oil supplementation may be explained by a remodeling of the plasma lipids into phospholipids and triglycerides of long-chain polyunsaturated fatty acids needs to be further investigated.
-
-
-
Hassani, Sahar; Martens, Harald; Qannari, El Mostafa; Hanafi, Mohamed; Borge, Grethe iren andersen & Kohler, Achim
(2010).
Analysis of -omics data: Graphical interpretation- and validation tools in multi-block methods.
Chemometrics and Intelligent Laboratory Systems.
ISSN 0169-7439.
104(1),
s. 140–153.
doi:
10.1016/j.chemolab.2010.08.008.
Vis sammendrag
As systems biology develops, various types of high-throughput -omics data become rapidly available. An increasing challenge is to analyze such massive data, interpret the results and validate the findings. Data analysis for most of the omics-techniques is in a fledgling immature stage. Alone the dimensionality of the data tables calls for new ways to reveal structure in the data, without cognitive overflow and excessive false discovery rate. Multi-block methods have been developed and adapted in order to find common variation patterns in data and depict these findings on graphical displays while providing tools to enhance the interpretation of the outcomes. In particular, multi-block methods based on latent variables are powerful tools to study block and global variation patterns, e.g. by inspecting block and global score plots. These methods can be used to achieve a graphical overview over sample and variable variation patterns in an efficient way. However, a visual detection of patterns may be subjective and, therefore, there is a need for validation tools. In this paper tools for validation of visually identified patterns in multi-block results are presented. Cross-validated estimates of Root Mean Square Error (RMSE) for block results are introduced for estimating the number of relevant PCs of the Consensus Principal Component Analysis (CPCA) models. Furthermore, important variables are identified by approximate t-tests based on Procrustes-corrected jackknifing. For the assessment of the stability of score patterns, block stability plots are introduced. Outliers can be revealed graphically on block and global level by stability plots. (C) 2010 Elsevier B.V. All rights reserved.
Se alle arbeider i Cristin
-
Lindman, Anja Schou; Tomic, Oliver; Kristoffersen, Doris Tove; Hassani, Sahar & Helgeland, Jon
(2014).
30 days readmission among the elderly – a new quality indicator for hospital performance in Norway.
-
Ottestad, Inger; Vogt, Kjell Gjermund; Myhrstad, Mari; Borge, Grethe Iren Andersen; Hassani, Sahar & Kohler, Achim
[Vis alle 16 forfattere av denne artikkelen]
(2012).
Effect of oxidized fish oil on oxidative stress markers and plasma lipidome profile.A randomized controlled trial in healthy subjects.
-
Hassani, Sahar; Martens, Harald; Qannari, El Mostafa; Borge, Grethe Iren Andersen & Kohler, Achim
(2011).
Analysis of metabolomics data by means of multi-block methods.
-
Perisic, Nebojsa; Afseth, Nils Kristian; Ofstad, Ragni; Hassani, Sahar & Kohler, Achim
(2010).
Integrating information obtained by different spectroscopic techniques by multi-matrix techniques.
-
Perisic, Nebojsa; Afseth, Nils Kristian; Ofstad, Ragni; Hassani, Sahar & Kohler, Achim
(2010).
Integrating information obtained by different spectroscopic techniques by multi-matrix techniques.
-
Lindman, Anja Schou; Kristoffersen, Doris Tove; Hassani, Sahar; Tomic, Oliver & Helgeland, Jon
(2015).
30-dagers reinnleggelse av eldre 2011–2013. Resultater for sykehus og kommuner.
Nasjonalt kunnskapssenter for helsetjenesten.
ISSN 978-82-8121-950-2.
Fulltekst i vitenarkiv
-
Lindman, Anja Schou; Tomic, Oliver; Hassani, Sahar; Kristoffersen, Doris Tove & Helgeland, Jon
(2015).
30-dagers overlevelse - institusjonsrapporter - 2. utgave.
Norwegian Knowledge Centre for the Heath Services.
ISSN 978-82-8121-940-3.
-
Lindman, Anja Schou; Hassani, Sahar; Kristoffersen, Doris Tove; Tomic, Oliver; Dimoski, Tomislav & Helgeland, Jon
(2014).
30-dagers overlevelse og reinnleggelse ved norske sykehus for 2013.
Nasjonalt kunnskapssenter for helsetjenesten.
ISSN 978-82-8121-912-0.
Fulltekst i vitenarkiv
-
Lindman, Anja Schou; Tomic, Oliver; Hassani, Sahar; Kristoffersen, Doris Tove & Helgeland, Jon
(2014).
30-dagers overlevelse. Institusjonsrapporter.
Nasjonalt kunnskapssenter for helsetjenesten.
ISSN 978–82–8121–9328.
-
Helgeland, Jon; Kristoffersen, Doris Tove; Hassani, Sahar; Dimoski, Tomislav & Lindman, Anja Schou
(2013).
Overlevelse og reinnleggelser ved norske sykehus for 2012.
Nasjonalt kunnskapssenter for helsetjenesten.
ISSN 978-82-8121-831-4.
Fulltekst i vitenarkiv
Se alle arbeider i Cristin
Publisert
1. mars 2022 15:47
- Sist endret
12. feb. 2024 10:40