Volkert Siersma
Biographic Data
| ID | 359711 |
|---|---|
| NAME | Volkert Siersma |
| GIVEN NAMES | Volkert |
| FAMILY NAME | Siersma |
| SIGNATURE | SIERSMA V |
| AFFILIATIONS | University of Copenhagen |
| ORCID | 0000-0003-1941-2681 |
| VERIFIED | Yes |
| TOTAL WORKS | 20 |
| TOTAL CITATIONS | 723 |
| AUTHOR COUNT | 20 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 2009 |
| LATEST PUBLICATION YEAR | 2025 |
| H-INDEX | 2 |
The Multimorbidity Questionnaire (MMQ1): English translation and validation of a Danish patient reported outcome measure for quality of life in people with multiple long-term conditions in a cross-sec…
The English-language MMQ1 demonstrated adequate psychometric properties using classical test theory. Further validation using Rasch analysis is planned, and may help optimise and abbreviate the measure. This PROM has the potential to improve the measurement of QOL in MLTC research, including trials
Downstream healthcare use following breast cancer screening: A register-based cohort study
BACKGROUND: For evaluation of breast cancer screening and informed prioritisation, it is important to examine the downstream healthcare use associated to participation. The objective of this study is to determine the healthcare use among breast cancer screening participants compared with screening-naïve controls. METHODS: The study is a register-based cohort study with 14 years of follow-up. We compare healthcare use among women who participated …
Labour market attachment dynamics in patients with concussion: A Danish nationwide register-based cohort study
Concussion was associated with enhanced risk of adverse transitions between labour market states and lower occurrence of favourable transitions, indicating work disability, potentially due to persistent post-concussive symptoms. Some age groups, individuals with high income, and employees with management experience may be more affected
Evaluation of the Danish version of the prenatal parental reflective functioning questionnaire in early pregnancy as a screening tool
Parental reflective functioning (PRF) is the capacity to focus on feelings and experiences in oneself as a parent and in the child. Research has demonstrated that, the better the PRF the better outcomes for the child. This paper evaluated the Danish version of the prenatal parental reflective functioning questionnaire (P‐PRFQ). We used data from a cluster‐randomized trial of pregnant women recruited from Danish general practice. The sample includ…
Effects of Implementing the Short-Term Assessment of Risk and Treatability for Mechanical Restraint in a Forensic Male Population: A Stepped-Wedge, Cluster-Randomized Design
The assessment and formulation of the risk of violence and other unwanted behaviors at forensic psychiatric facilities have been attempted for decades. Structured professional judgment tools, such as the Short-Term Assessment of Risk and Treatability (START), are among the recent attempts to overcome the challenge of accomplishing these goals. This study examined the effect of implementing START in clinical practice for the most serious adverse e…
What factors are most important for the development of the maternal–fetal relationship? A prospective study among pregnant women in Danish general practice
Pregnant women reporting lack of social support and general low physical and mental well-being early in pregnancy may be at risk for developing a poor MAA. An approach targeting both psychosocial and physiological well-being may positively influence expectant mothers' successful adaptation to motherhood
Consequences of screening in colorectal cancer (COS-CRC): Development and dimensionality of a questionnaire
An extended version of COS specifically for use in a CRC screening setting has been developed. The extended part encompasses four new scales and one new single item. The original COS with the CRC-screening specific extension is called consequences of screening in colorectal cancer (COS-CRC). COS-CRC possessed reliability, unidimensionality and invariant measurement
Psychosocial consequences of invitation to colorectal cancer screening: A matched cohort study
BACKGROUND: Psychosocial consequences of colorectal cancer (CRC) screening can arise anywhere in the screening cascade. Previous studies have investigated the consequences of participating in CRC screening; however, we have not identified any studies investigating the psychosocial consequences of receiving the invitation. Therefore, the objective of this study was to investigate psychosocial consequences of invitation to CRC screening. METHODS: T…
Health-Related Quality of Life and Physical Function in Individuals with Parkinson’s Disease after a Multidisciplinary Rehabilitation Regimen—A Prospective Cohort Feasibility Study
Parkinson's disease (PD) is a neurodegenerative disease and a multidisciplinary approach to rehabilitation has been suggested as the best clinical practice. However, very few studies have investigated the long-term effects of a multidisciplinary rehabilitation approach, particularly regarding whether this can slow the progression of PD. The purpose was to investigate the short- and long-term effect of a 2-week multidisciplinary rehabilitation reg…
Consequences of screening in cervical cancer: Development and dimensionality of a questionnaire
The reliability and the dimensionality of a condition-specific measure with high content validity for women having an abnormal cervical cancer screening results have been demonstrated. This new questionnaire called Consequences Of Screening in Cervical Cancer (COS-CC) covers in two parts the psychosocial experience in cervical cancer screening
Mortality Following Trajectories of Mobility Limitations: The Modifying Impact of Social Factors
Objective: How are trajectories of mobility limitations (MLs) among older adults associated with mortality? Do social factors modify these associations? Method: Group-based trajectory modeling was used to identify four trajectories of MLs over a period of 4.5 years among 3,055 older Danes. Mortality analyses were conducted using additive hazard regression models. Results: Compared to older adults without MLs, older adults with high level of MLs w…
How does HPV vaccination status relate to risk perceptions and intention to participate in cervical screening? a survey study
HPV vaccinated women more often than unvaccinated women intended to participate in screening and they perceived cervical cancer risk to be higher and the vaccine effect to be larger than unvaccinated women did. However, in our analyses, risk perceptions could not explain screening intentions neither among vaccinated nor among unvaccinated women
Health-related quality of life in patients with chronic rheumatic disease after a multidisciplinary rehabilitation regimen
Sample Size in Qualitative Interview Studies: Guided by Information Power
Sample sizes must be ascertained in qualitative studies like in quantitative studies but not by the same means. The prevailing concept for sample size in qualitative studies is "saturation." Saturation is closely tied to a specific methodology, and the term is inconsistently applied. We propose the concept "information power" to guide adequate sample size for qualitative studies. Information power indicates that the more information the sample ho…
Missing portion sizes in FFQ – alternatives to use of standard portions
Objective Standard portions or substitution of missing portion sizes with medians may generate bias when quantifying the dietary intake from FFQ. The present study compared four different methods to include portion sizes in FFQ. Design We evaluated three stochastic methods for imputation of portion sizes based on information about anthropometry, sex, physical activity and age. Energy intakes computed with standard portion sizes, defined as sex-sp…
Mobility decline in old age: The combined effect of mobility-related fatigue and socioeconomic position
BACKGROUND: Mobility-related fatigue and low socioeconomic position predicts mobility limitations and disability in old age, but the interplay between these two factors is unknown. To evaluate whether mobility-related fatigue is a stronger risk factor for mobility limitations in certain socioeconomic groups, the aim of this study was to examine the combined effect of mobility-related fatigue and socioeconomic position on mobility limitations in a…
Impact of Social Capital on 8-Year Mortality Among Older People in 34 Danish Municipalities
The measures of social capital used in the present study include key aspects of social capital that are associated to mortality in older populations via physical activity and mobility disability
Prevalence and progression of visual impairment in patients newly diagnosed with clinical type 2 diabetes: A 6-year follow up study
In a comprehensive assessment of predictors of visual impairment, even in a health care system allowing self-referral to free eye examinations, treatable eye pathologies such as DR and cataract emerge together with age as the most notable predictors of continued visual loss after diabetes diagnosis. Our results underline the importance of eliminating barriers to efficient eye care by increasing patients' and primary care practitioners' awareness …
Year Excess All-Cause Mortality of Newly Diagnosed Type 2 Diabetic Patients: A cohort study
We found an excess mortality of type 2 diabetic patients compared with the background population in all age groups. The excess mortality was most pronounced in men and in young patients
A Coefficient of Association Between Categorical Variables With Partial or Tentative Ordering of Categories
Goodman and Kruskal’s γ coefficient measuring monotone association and its partial variants are useful for the analysis of multiway contingency tables containing ordinal variables. When the categories of a variable are only partly ordered and the variable is treated as a nominal variable, information in the ordering of the categories and statistical power is lost. The authors suggest a P γ measure that is the maximum of the ordinary γ coefficient…
Sample Size in Qualitative Interview Studies: Guided by Information Power
Sample sizes must be ascertained in qualitative studies like in quantitative studies but not by the same means. The prevailing concept for sample size in qualitative studies is "saturation." Saturation is closely tied to a specific methodology, and the term is inconsistently applied. We propose the concept "information power" to guide adequate sample size for qualitative studies. Information power indicates that the more information the sample ho…
Impact of Social Capital on 8-Year Mortality Among Older People in 34 Danish Municipalities
The measures of social capital used in the present study include key aspects of social capital that are associated to mortality in older populations via physical activity and mobility disability
Evaluation of the Danish version of the prenatal parental reflective functioning questionnaire in early pregnancy as a screening tool
Parental reflective functioning (PRF) is the capacity to focus on feelings and experiences in oneself as a parent and in the child. Research has demonstrated that, the better the PRF the better outcomes for the child. This paper evaluated the Danish version of the prenatal parental reflective functioning questionnaire (P‐PRFQ). We used data from a cluster‐randomized trial of pregnant women recruited from Danish general practice. The sample includ…
Year Excess All-Cause Mortality of Newly Diagnosed Type 2 Diabetic Patients: A cohort study
We found an excess mortality of type 2 diabetic patients compared with the background population in all age groups. The excess mortality was most pronounced in men and in young patients
A Coefficient of Association Between Categorical Variables With Partial or Tentative Ordering of Categories
Goodman and Kruskal’s γ coefficient measuring monotone association and its partial variants are useful for the analysis of multiway contingency tables containing ordinal variables. When the categories of a variable are only partly ordered and the variable is treated as a nominal variable, information in the ordering of the categories and statistical power is lost. The authors suggest a P γ measure that is the maximum of the ordinary γ coefficient…
Prevalence and progression of visual impairment in patients newly diagnosed with clinical type 2 diabetes: A 6-year follow up study
In a comprehensive assessment of predictors of visual impairment, even in a health care system allowing self-referral to free eye examinations, treatable eye pathologies such as DR and cataract emerge together with age as the most notable predictors of continued visual loss after diabetes diagnosis. Our results underline the importance of eliminating barriers to efficient eye care by increasing patients' and primary care practitioners' awareness …
Impact of Social Capital on 8-Year Mortality Among Older People in 34 Danish Municipalities
The measures of social capital used in the present study include key aspects of social capital that are associated to mortality in older populations via physical activity and mobility disability
Mobility decline in old age: The combined effect of mobility-related fatigue and socioeconomic position
BACKGROUND: Mobility-related fatigue and low socioeconomic position predicts mobility limitations and disability in old age, but the interplay between these two factors is unknown. To evaluate whether mobility-related fatigue is a stronger risk factor for mobility limitations in certain socioeconomic groups, the aim of this study was to examine the combined effect of mobility-related fatigue and socioeconomic position on mobility limitations in a…
Missing portion sizes in FFQ – alternatives to use of standard portions
Objective Standard portions or substitution of missing portion sizes with medians may generate bias when quantifying the dietary intake from FFQ. The present study compared four different methods to include portion sizes in FFQ. Design We evaluated three stochastic methods for imputation of portion sizes based on information about anthropometry, sex, physical activity and age. Energy intakes computed with standard portion sizes, defined as sex-sp…
How does HPV vaccination status relate to risk perceptions and intention to participate in cervical screening? a survey study
HPV vaccinated women more often than unvaccinated women intended to participate in screening and they perceived cervical cancer risk to be higher and the vaccine effect to be larger than unvaccinated women did. However, in our analyses, risk perceptions could not explain screening intentions neither among vaccinated nor among unvaccinated women
Health-related quality of life in patients with chronic rheumatic disease after a multidisciplinary rehabilitation regimen
Sample Size in Qualitative Interview Studies: Guided by Information Power
Sample sizes must be ascertained in qualitative studies like in quantitative studies but not by the same means. The prevailing concept for sample size in qualitative studies is "saturation." Saturation is closely tied to a specific methodology, and the term is inconsistently applied. We propose the concept "information power" to guide adequate sample size for qualitative studies. Information power indicates that the more information the sample ho…
Consequences of screening in cervical cancer: Development and dimensionality of a questionnaire
The reliability and the dimensionality of a condition-specific measure with high content validity for women having an abnormal cervical cancer screening results have been demonstrated. This new questionnaire called Consequences Of Screening in Cervical Cancer (COS-CC) covers in two parts the psychosocial experience in cervical cancer screening
Mortality Following Trajectories of Mobility Limitations: The Modifying Impact of Social Factors
Objective: How are trajectories of mobility limitations (MLs) among older adults associated with mortality? Do social factors modify these associations? Method: Group-based trajectory modeling was used to identify four trajectories of MLs over a period of 4.5 years among 3,055 older Danes. Mortality analyses were conducted using additive hazard regression models. Results: Compared to older adults without MLs, older adults with high level of MLs w…
Health-Related Quality of Life and Physical Function in Individuals with Parkinson’s Disease after a Multidisciplinary Rehabilitation Regimen—A Prospective Cohort Feasibility Study
Parkinson's disease (PD) is a neurodegenerative disease and a multidisciplinary approach to rehabilitation has been suggested as the best clinical practice. However, very few studies have investigated the long-term effects of a multidisciplinary rehabilitation approach, particularly regarding whether this can slow the progression of PD. The purpose was to investigate the short- and long-term effect of a 2-week multidisciplinary rehabilitation reg…
What factors are most important for the development of the maternal–fetal relationship? A prospective study among pregnant women in Danish general practice
Pregnant women reporting lack of social support and general low physical and mental well-being early in pregnancy may be at risk for developing a poor MAA. An approach targeting both psychosocial and physiological well-being may positively influence expectant mothers' successful adaptation to motherhood
Consequences of screening in colorectal cancer (COS-CRC): Development and dimensionality of a questionnaire
An extended version of COS specifically for use in a CRC screening setting has been developed. The extended part encompasses four new scales and one new single item. The original COS with the CRC-screening specific extension is called consequences of screening in colorectal cancer (COS-CRC). COS-CRC possessed reliability, unidimensionality and invariant measurement
Psychosocial consequences of invitation to colorectal cancer screening: A matched cohort study
BACKGROUND: Psychosocial consequences of colorectal cancer (CRC) screening can arise anywhere in the screening cascade. Previous studies have investigated the consequences of participating in CRC screening; however, we have not identified any studies investigating the psychosocial consequences of receiving the invitation. Therefore, the objective of this study was to investigate psychosocial consequences of invitation to CRC screening. METHODS: T…
Effects of Implementing the Short-Term Assessment of Risk and Treatability for Mechanical Restraint in a Forensic Male Population: A Stepped-Wedge, Cluster-Randomized Design
The assessment and formulation of the risk of violence and other unwanted behaviors at forensic psychiatric facilities have been attempted for decades. Structured professional judgment tools, such as the Short-Term Assessment of Risk and Treatability (START), are among the recent attempts to overcome the challenge of accomplishing these goals. This study examined the effect of implementing START in clinical practice for the most serious adverse e…
Labour market attachment dynamics in patients with concussion: A Danish nationwide register-based cohort study
Concussion was associated with enhanced risk of adverse transitions between labour market states and lower occurrence of favourable transitions, indicating work disability, potentially due to persistent post-concussive symptoms. Some age groups, individuals with high income, and employees with management experience may be more affected
Evaluation of the Danish version of the prenatal parental reflective functioning questionnaire in early pregnancy as a screening tool
Parental reflective functioning (PRF) is the capacity to focus on feelings and experiences in oneself as a parent and in the child. Research has demonstrated that, the better the PRF the better outcomes for the child. This paper evaluated the Danish version of the prenatal parental reflective functioning questionnaire (P‐PRFQ). We used data from a cluster‐randomized trial of pregnant women recruited from Danish general practice. The sample includ…
The Multimorbidity Questionnaire (MMQ1): English translation and validation of a Danish patient reported outcome measure for quality of life in people with multiple long-term conditions in a cross-sec…
The English-language MMQ1 demonstrated adequate psychometric properties using classical test theory. Further validation using Rasch analysis is planned, and may help optimise and abbreviate the measure. This PROM has the potential to improve the measurement of QOL in MLTC research, including trials
Downstream healthcare use following breast cancer screening: A register-based cohort study
BACKGROUND: For evaluation of breast cancer screening and informed prioritisation, it is important to examine the downstream healthcare use associated to participation. The objective of this study is to determine the healthcare use among breast cancer screening participants compared with screening-naïve controls. METHODS: The study is a register-based cohort study with 14 years of follow-up. We compare healthcare use among women who participated …
Medicine (16 works) · Psychology (10 works) · Internal Medicine (8 works) · Cohort (6 works) · Danish (6 works) · Psychiatry (6 works) · Cohort study (5 works) · Demography (5 works) · Gerontology (5 works) · Global Cancer Incidence and Screening (5 works)