| 1. |
- Botvinik-Nezer, Rotem, et al.
(författare)
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Variability in the analysis of a single neuroimaging dataset by many teams
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 582, s. 84-88
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Tidskriftsartikel (refereegranskat)abstract
- Data analysis workflows in many scientific domains have become increasingly complex and flexible. Here we assess the effect of this flexibility on the results of functional magnetic resonance imaging by asking 70 independent teams to analyse the same dataset, testing the same 9 ex-ante hypotheses(1). The flexibility of analytical approaches is exemplified by the fact that no two teams chose identical workflows to analyse the data. This flexibility resulted in sizeable variation in the results of hypothesis tests, even for teams whose statistical maps were highly correlated at intermediate stages of the analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Notably, a meta-analytical approach that aggregated information across teams yielded a significant consensus in activated regions. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset(2-5). Our findings show that analytical flexibility can have substantial effects on scientific conclusions, and identify factors that may be related to variability in the analysis of functional magnetic resonance imaging. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for performing and reporting multiple analyses of the same data. Potential approaches that could be used to mitigate issues related to analytical variability are discussed. The results obtained by seventy different teams analysing the same functional magnetic resonance imaging dataset show substantial variation, highlighting the influence of analytical choices and the importance of sharing workflows publicly and performing multiple analyses.
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| 2. |
- Brütt, Katharina, et al.
(författare)
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Competition and moral behavior: A meta-analysis of forty-five crowd-sourced experimental designs
- 2023
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Ingår i: Proceedings of the National Academy of Sciences - PNAS. - : National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 120:23
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Tidskriftsartikel (refereegranskat)abstract
- Does competition affect moral behavior? This fundamental question has been debated among leading scholars for centuries, and more recently, it has been tested in experimental studies yielding a body of rather inconclusive empirical evidence. A potential source of ambivalent empirical results on the same hypothesis is design heterogeneity-variation in true effect sizes across various reasonable experimental research protocols. To provide further evidence on whether competition affects moral behavior and to examine whether the generalizability of a single experimental study is jeopardized by design heterogeneity, we invited independent research teams to contribute experimental designs to a crowd-sourced project. In a large-scale online data collection, 18,123 experimental participants were randomly allocated to 45 randomly selected experimental designs out of 95 submitted designs. We find a small adverse effect of competition on moral behavior in a meta-analysis of the pooled data. The crowd-sourced design of our study allows for a clean identification and estimation of the variation in effect sizes above and beyond what could be expected due to sampling variance. We find substantial design heterogeneity-estimated to be about 1.6 times as large as the average standard error of effect size estimates of the 45 research designs-indicating that the informativeness and generalizability of results based on a single experimental design are limited. Drawing strong conclusions about the underlying hypotheses in the presence of substantive design heterogeneity requires moving toward much larger data collections on various experimental designs testing the same hypothesis.
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| 3. |
- Dreber, Helena, et al.
(författare)
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Health-Related Quality of Life 5 Years After Roux-en-Y Gastric Bypass in Young (18-25 Years) Versus Older (≥ 26 Years) Adults : a Scandinavian Obesity Surgery Registry Study.
- 2019
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Ingår i: Obesity Surgery. - : Springer. - 0960-8923 .- 1708-0428. ; 29:2, s. 434-443
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: To compare changes in health-related quality of life (HRQoL) in young (18-25 years) versus older (≥ 26 years) adults up to 5 years after Roux-en-Y gastric bypass (RYGB).METHODS: Data on Short Form-36 (SF-36) and obesity-related problems scale (OP) at baseline and 1, 2, and 5 years after RYGB were extracted from the Scandinavian Obesity Surgery Registry. Within-group changes and the effect of age group on 5-year changes in SF-36 and OP were analyzed. Effects sizes (ESs) were calculated.RESULTS: A total of 2542 young and 12,425 older adults were included at baseline, and 138 young (20.7% of those eligible) and 1021 older (31.8%) adults were followed-up 5 years post-RYGB. At this time, average to large improvements (ES ≥ 0.5) were observed in physical functioning, physical component score and OP in young adults, and in physical functioning, role physical, general health, physical component score, and OP in older adults (all, p ≤ 0.001). Both age groups displayed negligible to weak (ES < 0.5) or no improvements in mental HRQoL (all, p < 0.55). Older adults displayed greater 5-year improvements than their young counterparts in role physical, general health, vitality, social functioning, physical component score, and obesity-related problems scale (all, p < 0.05).CONCLUSIONS: Both young and older adults displayed improvements in OP and physical HRQoL 5 years post-RYGB compared to baseline, while mental HRQoL did not improve to the same extent. Greater HRQoL-improvements could be expected in older patients why future research on HRQoL post-RYGB should stratify data on age groups.
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| 4. |
- Dreber, Helena
(författare)
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Severe obesity in young adults : characterization and treatment outcomes with emphasis on mental health aspects
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Obesity (body mass index [BMI] ≥30 kg/m2) is associated with a range of physical and psychiatric comorbidities and premature mortality. Young adulthood (here 16-25 years) constitutes a vulnerable period for weight gain, poor weight loss results, and mental health problems. Up to 8.3% of Swedish young adults are classified as obese. In spite of the fact that the peak incidence for obesity occurs during young adulthood, this age period has been generally overlooked in clinical obesity research, particularly in regard to obesity-related mental health problems. Aim: To characterize severe obesity (BMI ≥35 kg/m2) in young adulthood (16-25 years) with emphasis on mental health aspects, and to study long-term outcomes (weight loss, adverse events, loss-to-follow-up and health-related quality of life [HRQL]) in young (18-25 years) vs older (≥26 years) adults after Roux-en-Y gastric bypass (RYGB). Methods: In Study I, we used cross-sectional self-reported questionnaire data on obesity-related comorbidities, mental health, self-esteem, lifestyle and health-related quality of life; physical fitness tests; biochemical data on micronutritional deficiencies; and anthropometry from n=165 young adults, aged 16-25 years who were about to start treatment at the Karolinska University Hospital Obesity Center. In Study II, we compared cross-sectional questionnaire patient data (n=121 treatment-seekers to the Obesity Center, 18-25 years) on mental distress, self-reported suicide attempts, physical/psychosomatic symptoms, and quality of life with data on n=363 normal-weight responders to the Stockholm Public Health Cohort 2010 who were individually matched 3:1 for age, gender and socioeconomic status. For Studies III-IV, we frequency matched n=3,531 young (18-25 years) to n=17,137 older (26-74 years) patients in the Scandinavian Obesity Surgery Registry for BMI, gender and year of surgery to compare weight loss, adverse events, loss-to-follow-up and changes in HRQL between matching groups. Results: In Study I, we found consistent indications of poor mental and obesity-related health problems (up to 55%), high levels of cardiometabolic risk factors (up to 82%) and micronutritional deficiencies (48%) in treatment-seeking young adults (mean BMI 39.2 kg/m2 [SD: 5.2], 80% women). In Study II, we found an increased risk of mental distress (adjusted relative risk [RR]=1.76, 95% CI: 1.38-2.24), suicide attempts (adjusted RR=2.04, 95% CI: 1.06-3.95), physical/psychosomatic symptoms (adjusted RR=1.59-2.95) and poor quality of life (range of adjusted RR=1.97-6.61) in obese treatment-seekers (mean BMI 39.8 kg/m2 [SD: 5.3], 81% women) compared to population controls (mean BMI 22.4 kg/m2 [SD: 4.0], 81% women). In Study III, a total of n=369 young (37.0% of eligible) and n=2,210 older (46.1%) adults were followed-up 5 years after RYGB. Young adults displayed higher weight loss (31.8% vs 28.2%) at 5 years, more long-term adverse events (any kind of adverse events between 2-5 years: 20.3% vs 12.7%, adjusted OR=1.72, 95% CI: 1.29-2.31; serious adverse events between 2-5 years [Clavien-Dindo ≥3b]: 14.1% vs 6.9%, adjusted OR=2.06, 95% CI: 1.45-2.92) and higher loss-to-follow-up throughout the study period (range of adjusted RR=1.16-2.13), all, p <0.001. In Study IV, n=138 young (20.7% of those eligible) and n=1,021 older (31.8%) adults were available for follow-up 5 years post-RYGB. Both young and older adults displayed clinically relevant improvements in physical HRQL 5 years after RYGB compared to baseline values, while no change or deterioration in mental HRQL was observed in both groups. Older adults generally experienced greater HRQL improvements than the young adults in adjusted analyses. Conclusion: Treatment-seeking young adults with severe obesity constitute a vulnerable patient group with a wide array of obesity-related comorbidities, particularly mental health issues. While we found promising weight loss results and improvements in physical HRQL in young adults 5 years after RYGB, there were also higher numbers of long-term adverse events, drop-outs and generally poor improvements in HRQL in young vs older adults. Future research needs to address the impact of mental distress on the development and treatment of obesity in young adults. Studies on the significance of and the etiology behind our data showing more serious adverse events and higher loss-to-follow-up in the younger RYGB-patients are needed.
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| 5. |
- Dreber, Helena, et al.
(författare)
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Who is the Treatment-Seeking Young Adult with Severe Obesity : A Comprehensive Characterization with Emphasis on Mental Health.
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 104, s. 21-22
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To characterize treatment-seeking young adults (16-25 years) with severe obesity, particularly mental health problems.STUDY DESIGN AND PARTICIPANTS: Cross-sectional study of 165 participants (132 women, 33 men) with BMI ≥35 kg/m2 or ≥30 kg/m2 with comorbidities, enrolling in a multidisciplinary obesity treatment program.METHOD: Data collection at admission of present and life-time health issues including symptomatology of anxiety, depression (Hospital Anxiety and Depression Scale) and attention-deficit/hyperactivity disorder (Adult ADHD Self-Report scale); self-esteem (Rosenberg Self-Esteem Scale), suicide attempts, health-related quality of life (Short Form-36 Health Survey), psychosocial functioning related to obesity (Obesity-related Problems Scale), cardiorespiratory fitness (Astrand's bicycle ergometer test), somatic and psychiatric co-morbidities, cardiometabolic risk factors, and micronutritional status. We used multiple regression analysis to identify variables independently associated with present anxiety and depressive symptomatology.RESULTS: Mean body mass index was 39.2 kg/m2 (SD = 5.2). We found evidence of poor mental health, including present psychiatric diagnoses (29%), symptomatology of anxiety (47%), depression (27%) and attention-deficit/hyperactivity disorder (37%); low self-esteem (42%), attempted suicide (12%), and low quality of life (physical component score = 46, SD = 11.2; mental component score = 36, SD = 13.9, P<0.001 for difference). Variables independently associated with present anxiety symptomatology (R2 = 0.33, P<0.001) included low self-esteem (P<0.001) and pain (P = 0.003), whereas present depressive symptomatology (R2 = 0.38, P<0.001) was independently associated with low self-esteem (P<0.001), low cardiorespiratory fitness (P = 0.009) and obesity-related problems (P = 0.018). The prevalence of type 2 diabetes was 3%, and hypertension 2%. Insulin resistance was present in 82%, lipid abnormality in 62%, and poor cardiorespiratory fitness in 92%. Forty-eight percent had at least one micronutritional deficiency, vitamin D being the most common (35%).CONCLUSION: A wide range of health issues, including quite severe mental health problems, was prevalent in treatment-seeking young adults with severe obesity. These are likely to constitute a major treatment challenge, including options relating to bariatric surgery.
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| 6. |
- Hudson, Lawrence N, et al.
(författare)
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The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project
- 2017
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Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 7:1, s. 145-188
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Tidskriftsartikel (refereegranskat)abstract
- The PREDICTS project-Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)-has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.
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