| 1. |
- Björk, Jonas, et al.
(författare)
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Predicting participation in the population-based Swedish cardiopulmonary bio-image study (SCAPIS) using register data
- 2017
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Ingår i: Scandinavian Journal of Public Health. - : SAGE Publications. - 1403-4948 .- 1651-1905. ; 45, s. 45-49
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To illustrate the importance of access to register data on determinants and predictors of study participation to assess validity of population-based studies. In the present investigation, we use data on sociodemographic conditions and disease history among individuals invited to the Swedish cardiopulmonary bio-image study (SCAPIS) in order to establish a model that predicts study participation. Methods: The pilot study of SCAPIS was conducted within the city of Gothenburg, Sweden, in 2012, with 2243 invited individuals (50% participation rate). An anonymous data set for the total target population (n = 24,502) was made available by register authorities (Statistics Sweden and the National Board of Health and Welfare) and included indicators of invitation to and participation in SCAPIS along with register data on residential area, sociodemographic variables, and disease history. Propensity scores for participation were estimated using logistic regression. Results: Residential area, country of birth, civil status, education, occupational status, and disposable income were all associated with participation in multivariable models. Adding data on disease history only increased overall classification ability marginally. The associations with disease history were diverse with some disease groups negatively associated with participation whereas some others tended to increase participation. Conclusions: The present investigation stresses the importance of a careful consideration of selection effects in population-based studies. Access to detailed register data also for non-participants can in the statistical analysis be used to control for selection bias and enhance generalizability, thereby making the results more relevant for policy decisions.
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| 2. |
- Bonander, Carl, et al.
(författare)
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Correcting for selective participation in cohort studies using auxiliary register data without identification of non-participants
- 2021
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Ingår i: Scandinavian Journal of Public Health. - : SAGE Publications. - 1403-4948 .- 1651-1905. ; 49:4, s. 449-456
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Selective participation may hamper the validity of population-based cohort studies. The resulting bias can be alleviated by linking auxiliary register data to both the participants and the non-participants of the study, estimating propensity scores for participation and correcting for participation based on these. However, registry holders may not be allowed to disclose sensitive data on (invited) non-participants. Our aim is to provide guidance on how adequate bias correction can be achieved by using auxiliary register data but without disclosing information that could be linked to the subset of non-participants. Methods: We show how existing methods can be used to estimate generalisation weights under various data disclosure scenarios where invited non-participants are indistinguishable from uninvited ones. We also demonstrate how the methods can be implemented using Nordic register data. Results: Inverse-probability-of-sampling weights estimated within a random sample of the target population in which the non-respondents are disclosed are equivalent in expectation to analogous weights in a scenario where the non-participants and uninvited individuals from the population are indistinguishable. To minimise the risk of disclosure when the entire population is invited to participate, investigators should instead consider inverse-odds-of-sampling weights, a method that has previously been suggested for transporting study results to external populations. Conclusions: Generalisation weights can be estimated from auxiliary register data without disclosing information on invited non-participants.
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| 3. |
- Bonander, Carl, et al.
(författare)
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Participation weighting based on sociodemographic register data improved external validity in a population-based cohort study
- 2019
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Ingår i: Journal of Clinical Epidemiology. - : Elsevier BV. - 0895-4356. ; 108, s. 54-63
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate whether inverse probability of participation weighting (IPPW) using register data on sociodemographic and disease history variables can improve external validity in a cohort study with selective participation. Study Design and Setting: We fitted various IPPW models by logistic regression using register data for the participants (n = 1,111) and nonparticipants (n = 1,132) of a Swedish cohort study. For each of six diagnostic groups, we then estimated (1) weighted disease prevalence proportions and (2) weighted cross-sectional associations (odds ratios) between sociodemographic variables and disease prevalence. Using register data on the remaining individuals of the entire study population of men and women aged 50-64 years (n = 22,259), we addressed how the choice of variables used for IPPW influenced estimation errors. Results: Disease prevalence proportions were generally underestimated in the absence of IPPW but became markedly closer to population values after IPPW using sociodemographic variables. We found limited evidence of selective participation bias in association estimates, but IPPW improved external validity when bias was present. Conclusions: IPPW using sociodemographic register data can improve the external validity of disease prevalence estimates in cohort studies with selective participation. The performance of IPPW for association estimates merits further investigations in longitudinal settings and larger cohorts. © 2018 Elsevier Inc.
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| 4. |
- Bonander, Carl, et al.
(författare)
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The value of combining individual and small area sociodemographic data for assessing and handling selective participation in cohort studies: Evidence from the Swedish CardioPulmonary bioImage Study
- 2022
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 17:3
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Tidskriftsartikel (refereegranskat)abstract
- Objectives To study the value of combining individual- and neighborhood-level sociodemographic data to predict study participation and assess the effects of baseline selection on the distribution of metabolic risk factors and lifestyle factors in the Swedish CardioPulmonary bioImage Study (SCAPIS). Methods We linked sociodemographic register data to SCAPIS participants (n = 30,154, ages: 50-64 years) and a random sample of the study's target population (n = 59,909). We assessed the classification ability of participation models based on individual-level data, neighborhood-level data, and combinations of both. Standardized mean differences (SMD) were used to examine how reweighting the sample to match the population affected the averages of 32 cardiopulmonary risk factors at baseline. Absolute SMDs >0.10 were considered meaningful. Results Combining both individual-level and neighborhood-level data gave rise to a model with better classification ability (AUC: 71.3%) than models with only individual-level (AUC: 66.9%) or neighborhood-level data (AUC: 65.5%). We observed a greater change in the distribution of risk factors when we reweighted the participants using both individual and area data. The only meaningful change was related to the (self-reported) frequency of alcohol consumption, which appears to be higher in the SCAPIS sample than in the population. The remaining risk factors did not change meaningfully. Conclusions Both individual- and neighborhood-level characteristics are informative in assessing study selection effects. Future analyses of cardiopulmonary outcomes in the SCAPIS cohort can benefit from our study, though the average impact of selection on risk factor distributions at baseline appears small.
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| 5. |
- Gummesson, Anders, 1973, et al.
(författare)
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Non-alcoholic fatty liver disease is a strong predictor of coronary artery calcification in metabolically healthy subjects: A cross-sectional, population-based study in middle-aged subjects
- 2018
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- Objectives This study aims to estimate the relationship between non-alcoholic fatty liver disease (NAFLD) and measures of atherosclerotic cardiovascular disease (ASCVD), and to determine to what extent such relationships are modified by metabolic risk factors. The study was conducted in the population-based Swedish CArdioPulmonary bioImage Study (SCAPIS) pilot cohort (n = 1015, age 50-64 years, 51.2% women). NAFLD was defined as computed tomography liver attenuation <= 40 Hounsfield Units, excluding other causes of liver fat. Coronary artery calcification score (CACS) was assessed using the Agatston method. Carotid plaques and intima media thickness (IMT) were measured by ultrasound. Metabolic status was based on assessments of glucose homeostasis, serum lipids, blood pressure and inflammation. A propensity score model was used to balance NAFLD and non NAFLD groups with regards to potential confounders and associations between NAFLD status and ASCVD variables in relation to metabolic status were examined by logistic and generalized linear regression models. NAFLD was present in 106 (10.4%) of the subjects and strongly associated with obesity-related traits. NAFLD was significantly associated with CACS after adjustment for confounders and metabolic risk factors (OR 1.77, 95% CI 1.07-2.94), but not with carotid plaques and IMT. The strongest association between NAFLD and CACS was observed in subjects with few metabolic risk factors (n = 612 [60% of all] subjects with 0-1 out of 7 predefined metabolic risk factors; OR 5.94, 95% CI 2.13-16.6). NAFLD was independently associated with coronary artery calcification but not with measures of carotid atherosclerosis in this cohort. The association between NAFLD and CACS was most prominent in the metabolically healthy subjects.
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| 6. |
- Hjelmgren, Ola, et al.
(författare)
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Does retinopathy predict stroke recurrence in type 2 diabetes patients: A retrospective study?
- 2019
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Aims To study if retinopathy increases the risk of stroke recurrence in stroke patients with type 2 diabetes. Also, to study if stroke patients with type 2 diabetes have an increased risk of stroke recurrence compared to non-diabetics and if stroke patients with type 2 diabetes, regardless of retinopathy, have a higher incidence of carotid stenosis. Also, to study if stroke patients with type 2 diabetes retinopathy have increased incidence of carotid stenosis. We included 445 patients with type 2 diabetes mellitus and a matched control group of 445 patients without diabetes, who had all suffered their first stroke or TIA. Information on retinopathy, risk factors and stroke recurrence were obtained from registers and medical records. Retinopathy did not increase the risk of stroke recurrence in diabetes patients, HR 0.89 (0.51-1.53), p = 0.67. The risk of stroke recurrence was not increased in diabetics compared to non-diabetes. Diabetes patients had an increased prevalence of carotid stenosis compared to non-diabetics, 1.69 (1.15-2.48), p = 0.008. The prevalence of carotid stenosis in diabetics with retinopathy was not increased compared to diabetics without retinopathy. Retinopathy is not a predictor of stroke recurrence or carotid stenosis in type 2 diabetes patients.
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| 7. |
- Roswall, Josefine, et al.
(författare)
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Overweight at four years of age in a Swedish birth cohort: influence of neighbourhood-level purchasing power
- 2016
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Ingår i: BMC Public Health. - London : Springer Science and Business Media LLC. - 1471-2458. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A number of child/parental factors have been shown to be significant predictors of childhood overweight, although a better understanding of possible contextual influences of neighbourhood-level characteristics might provide new insights leading to tailored, targeted interventions. The aim of this study was to explore the impact of neighbourhood purchasing power and its relationship with other known risk factors related to childhood overweight in a prospective birth cohort. METHODS: A prospective, population-based, birth-cohort study was conducted in south-western Sweden, comprising 2,666 infants born in 2007-2008. Childhood overweight was assessed by body mass index (BMI) data from follow-up examinations at four years of age (n=2,026) and overweight defined according to the International Obesity Task Force. Using logistic regression analysis, the influential child/parental predictors were identified from the candidate predictors, viz. child's gender, as well as birth weight adjusted for gestational age and parental factors at recruitment, including maternal smoking status, maternal BMI (before pregnancy), paternal BMI and parental educational level. The children's residential parishes at follow-up were stratified by parish-level household purchasing power (<10 %, 10-19.9 %, 20-29.9 % and ≥30 % of all resident families with low purchasing power) and the "contextual" influence was analysed. In each such neighbourhood stratum, the adjusted overweight ratio (AOR), i.e. the ratio between the observed number of overweight children and the expected number, taking account of the influential child/parental predictors, was estimated. RESULTS: The prevalence of overweight at four years of age was 11.9 %. In the economically strongest neighbourhoods (i.e. <10 % of resident families with low purchasing power), the AOR was 0.60 (95 % confidence interval (CI): 0.34-0.98). The corresponding empirically Bayes-adjusted AOR was 0.73 (95 % CI: 0.46-1.02; 97 % posterior probability of AOR<1). In the other neighbourhood strata, the statistical evidence of a deviant AOR was weaker. CONCLUSION: The economically strongest neighbourhoods had a lower prevalence than expected of overweight at four years of age. This finding should prompt studies to acquire more knowledge of potentially modifiable factors that differ between neighbourhoods and are related to childhood overweight, providing a basis for tailored, targeted interventions.
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| 8. |
- Szakacs, Attila, et al.
(författare)
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A population-based and case-controlled study of children and adolescents with narcolepsy: Health-related quality of life, adaptive behavior and parental stress
- 2019
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Ingår i: European Journal of Paediatric Neurology. - : Elsevier BV. - 1090-3798. ; 23:2, s. 288-295
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate health-related quality of life (HrQoL) and adaptive behavior in young people with narcolepsy and stress among their parents. Methods: In a cross-sectional exploratory quantitative study design, 37 young people with narcolepsy (8-20 years of age) and their parents were recruited. Thirty-one had post-H1N1 vaccination-related narcolepsy (PHV) and six had narcolepsy not related to PHV (nPHV). In addition, 40 age- and gender-matched controls (aged 5-20 years) were recruited. Results: Thirty-one patients completed the generic HrQoL questionnaire KIDSCREEN and the disease-specific NARQoL-21. HrQoL was found to be significantly diminished in all domains in the PHV group (p = 0.001) and in the School/Concentration domain (p = 0.004) in the nPHV group compared to age- and gender-matched controls. The Adaptive Behavior Assessment System was completed by parents of 32 patients. They rated their children significantly lower in the General adaptive composite (p = 0.026) and the Conceptual (p = 0.050) and Social composite scores (p = 0.001) compared with reference data on healthy Swedish children's and young people's adaptive behavior. Parents of 36 patients filled in the 36-item short form of the Parenting Stress Index questionnaire. They rated significantly higher Total stress, Parent-child dysfunctional interaction, and Difficult child scores compared with parents of controls (p = 0.001, p = 0.005, p < 0.001). Conclusions: Children with narcolepsy have diminished HrQoL compared with controls. Parents of children with narcolepsy experience impaired adaptive behavior in their children and high levels of parenting stress. Identifying the contributory factors is necessary, and early intervention is crucial in order to improve the HrQoL of these children and their families. (C) 2019 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.
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| 9. |
- Almquist-Tangen, Gerd, et al.
(författare)
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Influence of neighbourhood purchasing power on breastfeeding at four months of age : a Swedish population-based cohort study
- 2013
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Ingår i: BMC Public Health. - London : BioMed Central. - 1471-2458. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Parental socioeconomic status (SES) is an important determinant in child health, influencing beneficial factors such as breastfeeding. A better understanding of the influence of neighbourhood-level SES measures, relating to spatial determinants, might lead to targeted actions to promote breastfeeding during infancy.METHODS: A cross-sectional study analysis the association between breastfeeding at four months of age and neighbourhood purchasing power, taking account of individual-level variables including maternal age, smoking and parental level of education. Data were obtained from a prospective population- based cohort study recruited from birth in 2007-2008 in the Halland region, southwestern Sweden. Questionnaire data on the individual-level variables and the outcome variable of breastfeeding at four months (yes/no) were used (n=2,407). Each mother was geo-coded with respect to her residential parish (there are 61 parishes in the region) and then stratified by parish-level household purchasing power. It emerged that four neighbourhood characteristics were reasonable to use, viz. <10%, 10-19%, 20-29% and ≥ 30% of the resident families with low purchasing power.RESULTS: The proportion of mothers not breastfeeding at four months of age showed a highly significant trend across the neighbourhood strata (p=0.00004): from 16.3% (< 10% with low purchasing power) to 29.4% (≥ 30% with low purchasing power), yielding an OR of 2.24 (95% confidence interval: 1.45-3.16). After adjusting for the individual-level variables, the corresponding OR=1.63 (1.07-2.56) was significant and the trend across the strata was still evident (p=0.05). A multi-level analysis estimated that, in the neighbourhoods with ≥ 30% of the families with low purchasing power, 20% more mothers than expected, taking account of the individual-level factors, reported no breastfeeding at four months of age (≥ 95% posterior probability of an elevated observed-to-expected ratio).CONCLUSION: The neighbourhood purchasing power provided a spatial determinant of low numbers of mothers breastfeeding at four months of age, which could be relevant to consider for targeted actions. The elevated observed-to-expected ratio in the neighbourhoods with the lowest purchasing power points toward a possible contextual influence. © 2013 Almquist-Tangen et al.; licensee BioMed Central Ltd.
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| 10. |
- Björk, Jonas, et al.
(författare)
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A novel framework for classification of selection processes in epidemiological research
- 2020
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Ingår i: Bmc Medical Research Methodology. - : Springer Science and Business Media LLC. - 1471-2288. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Selection and selection bias are terms that lack consistent definitions and have varying meaning and usage across disciplines. There is also confusion in current definitions between underlying mechanisms that lead to selection and their consequences. Consequences of selection on study validity must be judged on a case-by-case basis depending on research question, study design and analytical decisions. The overall aim of the study was to develop a simple but general framework for classifying various types of selection processes of relevance for epidemiological research. Methods Several original articles from the epidemiological literature and from related areas of observational research were reviewed in search of examples of selection processes, used terminology and description of the underlying mechanisms. Results We classified the identified selection processes in three dimensions: i) selection level (selection at the population level vs. study-specific selection), ii) type of mechanism (selection in exposure vs. selection in population composition), iii) timing of the selection (at exposure entry, during exposure/follow-up or post-outcome). Conclusions Increased understanding of when, how, and why selection occur is an important step towards improved validity of epidemiological research.
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