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Papers by Daan van Schalkwijk

Research paper thumbnail of Hope for Students in an Information Age

Journal of Polian Studies, 2022

In this introduction, I will situate Polo’s article on hope within the context of the project to ... more In this introduction, I will situate Polo’s article on hope within the context of the project to introduce Polo’s thought to English-speaking educational institutions. To this end, my aim is four-fold. First, I will highlight the relevance of Polo’s thought for education. Second, I will relate the article on hope to Polo’s thought more generally. Third, I will provide an overview of the content of the paper. And fourth, I will discuss the significance of this paper for young people in our information age.

Research paper thumbnail of See Profile

Diagnostic markers based on a computational model of lipoprotein metabolism

Research paper thumbnail of Maternal Underestimation of Child’s Weight at Pre-School Age and Weight Development between Age 5 and 12 Years: The ABCD-Study

International Journal of Environmental Research and Public Health, 2020

Background: Healthcare monitoring of child growth reduces with age, which may increase parental i... more Background: Healthcare monitoring of child growth reduces with age, which may increase parental influences on children’s weight development. This study aimed to examine the association between maternal underestimation of child’s weight at age 5/6 and weight development between 5 and 12 years. Methods: We performed univariate and multivariate linear regression analyses with data on maternal perception of child’s weight and weight development (∆SDS body-mass index; BMI) derived from the Amsterdam Born Children and their Development (ABCD) birth-cohort study. Underestimation was defined by comparing maternal perception of child’s weight with the actual weight status of her child. Associations were studied in two groups: children with overweight (n = 207) and children with normal weight (n = 1982) at baseline (children with underweight were excluded). Results: Underestimation was 5.5% in children with normal weight and 79.7% in children with overweight. Univariate analyses in children w...

Research paper thumbnail of Machine learning modelling of blood lipid biomarkers in familial hypercholesterolaemia versus polygenic/environmental dyslipidaemia

Scientific Reports, 2021

Familial hypercholesterolaemia increases circulating LDL-C levels and leads to premature cardiova... more Familial hypercholesterolaemia increases circulating LDL-C levels and leads to premature cardiovascular disease when undiagnosed or untreated. Current guidelines support genetic testing in patients complying with clinical diagnostic criteria and cascade screening of their family members. However, most of hyperlipidaemic subjects do not present pathogenic variants in the known disease genes, and most likely suffer from polygenic hypercholesterolaemia, which translates into a relatively low yield of genetic screening programs. This study aims to identify new biomarkers and develop new approaches to improve the identification of individuals carrying monogenic causative variants. Using a machine-learning approach in a paediatric dataset of individuals, tested for disease causative genes and with an extended lipid profile, we developed new models able to classify familial hypercholesterolaemia patients with a much higher specificity than currently used methods. The best performing models...

Research paper thumbnail of Rank reversals in tree growth along tree size, competition and climatic

gradients for four forest canopy dominant species in Central Spain*

Research paper thumbnail of Rank reversals in tree growth along tree size, competition and climatic gradients for four forest canopy dominant species in Central

Research paper thumbnail of Improved cholesterol phenotype analysis by a model relating lipoprotein life cycle processes to particle size

The Journal of Lipid Research, 2009

Research paper thumbnail of Computational models for analyzing lipoprotein profiles

Clinical Lipidology, 2011

Research paper thumbnail of Rank reversals in tree growth along tree size, competition and climatic gradients for four forest canopy dominant species in Central Spain

Annals of Forest Science, 2008

Research paper thumbnail of Diagnostic markers based on a computational model of lipoprotein metabolism

Journal of clinical bioinformatics, 2011

Dyslipidemia is an important risk factor for cardiovascular disease and type II diabetes. Lipopro... more Dyslipidemia is an important risk factor for cardiovascular disease and type II diabetes. Lipoprotein diagnostics, such as LDL cholesterol and HDL cholesterol, help to diagnose these diseases. Lipoprotein profile measurements could improve lipoprotein diagnostics, but interpretational complexity has limited their clinical application to date. We have previously developed a computational model called Particle Profiler to interpret lipoprotein profiles. In the current study we further developed and calibrated Particle Profiler using subjects with specific genetic conditions. We subsequently performed technical validation and worked at an initial indication of clinical usefulness starting from available data on lipoprotein concentrations and metabolic fluxes. Since the model outcomes cannot be measured directly, the only available technical validation was corroboration. For an initial indication of clinical usefulness, pooled lipoprotein metabolic flux data was available from subjects ...

Research paper thumbnail of Rank reversals in tree growth along tree size, competition and climatic

gradients for four forest canopy dominant species in Central Spain*

Research paper thumbnail of Transcendence and Love for a New Global Society Proceedings of the II International Congress Transcendence and Love for a New Global Society

There is no dispute in neuroscience that structure and function are related, but it is difficult ... more There is no dispute in neuroscience that structure and function are related, but it is difficult to identify how exactly this relationship occurs. The phrenological view advocates for the idea that each area of the brain corresponds to a particular function. This view then evolved into a modular view, meaning that each brain network corresponds to a singular function. But these views have serious limitations and a more systemic one is in order. It is thought that brain function is related to dynamic and temporary neural assemblies. What seems obvious is that the relationship between structure and function is not straightforward. In this article, we will see how the non-function of brain areas and the non-univocal relationship between structure and function can serve as an opportunity to offer a new concept, i.e., “functionalization”, which the philosopher Leonardo Polo proposed. Polo understood functionalization as a part of function. We believe that the presence of this “intermedia...

Research paper thumbnail of Differential associations between psychosocial stress and obesity among Ghanaians in Europe and in Ghana: findings from the RODAM study

Social Psychiatry and Psychiatric Epidemiology

Purpose Psychosocial stress is associated with obesity in some populations, but it is unclear whe... more Purpose Psychosocial stress is associated with obesity in some populations, but it is unclear whether the association is related to migration. This study explored associations between psychosocial stress and obesity among Ghanaian migrants in Europe and non-migrant Ghanaians in Ghana. Methods Cross-sectional data from the RODAM study were used, including 5898 Ghanaians residing in Germany, the UK, the Netherlands, rural Ghana, and urban Ghana. Perceived discrimination, negative life events and stress at work or at home were examined in relation to body mass index (BMI) and waist circumference (WC). Linear regression analyses were performed separately for migrants and non-migrants stratified by sex. Results Perceived discrimination was not associated with BMI and WC in both migrants and non-migrants. However, negative life events were positively associated with BMI (β = 0.78, 95% CI 0.34-1.22) and WC (β = 1.96, 95% CI 0.79-3.12) among male Ghanaian migrants. Similarly, stress at work or at home was positively associated with BMI (β = 0.28, 95% CI 0.00-0.56) and WC (β = 0.84, 95% CI 0.05-1.63) among male Ghanaian migrants. Among non-migrant Ghanaians, in contrast, stress at work or at home was inversely associated with BMI and WC in both males (β = − 0.66, 95% CI − 1.03 to − 0.28; β = − 1.71 95% CI − 2.69 to − 0.73, respectively) and females (β = − 0.81, 95% CI − 1.20 to − 0.42; β = − 1.46, 95% CI − 2.30 to − 0.61, respectively). Conclusions Negative life events and stress at work or at home are associated with increased body weight among male Ghanaians in European settings, whereas stress at work or at home is associated with reduced body weight among Ghanaians in Ghana. More work is needed to understand the underlying factors driving these differential associations to assist prevention efforts.

Research paper thumbnail of Effect of body fat distribution on the physiological response to a dietary fat intervention

The Faseb Journal, Apr 1, 2009

Research paper thumbnail of The effect of plant sterols and different low doses of omega-3 fatty acids from fish oil on lipoprotein subclasses

Molecular Nutrition & Food Research, 2015

Consumption of a low-fat spread enriched with plant sterols (PS) and different low doses (&am... more Consumption of a low-fat spread enriched with plant sterols (PS) and different low doses (<2 g/day) of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil reduces serum triglycerides (TGs) and low-density lipoprotein-cholesterol (LDL-Chol) and thus beneficially affects two blood lipid risk factors. Yet, their combined effects on TG and Chol in various lipoprotein subclasses have been investigated to a limited extent. In a randomized, double-blind, placebo-controlled, parallel study, we determined TG and Chol in 13 LP subclasses in fasting serum of 282 hypercholesterolemic subjects, who consumed either a placebo spread or one of the four spreads containing PS (2.5 g/day) and EPA+DHA (0.0, 0.9, 1.3, and 1.8 g/day) for 4 weeks. After PS treatment, total LDL-Chol was reduced, which was not further changed by EPA+DHA. No shift in the LDL-Chol particle distribution was observed. The addition of EPA+DHA to PS dose-dependently reduced VLDL-Chol and VLDL-TG mainly in larger particles. Furthermore, the two highest doses of EPA+DHA increased Chol and TG in the larger HDL particles, while these concentrations were decreased in the smallest HDL particles. The consumption of a low-fat spread enriched with both PS and EPA+DHA induced shifts in the lipoprotein distribution that may provide additional cardiovascular benefits over PS consumption alone.

Research paper thumbnail of Candidate Diagnostics Indicating Lipoprotein Metabolism Status from a Single Blood Sample

Research paper thumbnail of MS327 Clustering by Plasma Lipoprotein Profile Reveals Large Fenofibrate Responder Subgroup

Atherosclerosis Supplements, 2010

Research paper thumbnail of Abstract: P934 DEVELOPING A MATHEMATICAL MODEL TO DETERMINE THE RATES OF LIPOPROTEIN METABOLIC PROCESSES FROM A SINGLE PLASMA SAMPLE

Atherosclerosis Supplements, 2009

Research paper thumbnail of Dietary medium chain fatty acid supplementation leads to reduced VLDL lipolysis and uptake rates in comparison to linoleic acid supplementation

PloS one, 2014

Dietary medium chain fatty acids (MCFA) and linoleic acid follow different metabolic routes, and ... more Dietary medium chain fatty acids (MCFA) and linoleic acid follow different metabolic routes, and linoleic acid activates PPAR receptors. Both these mechanisms may modify lipoprotein and fatty acid metabolism after dietary intervention. Our objective was to investigate how dietary MCFA and linoleic acid supplementation and body fat distribution affect the fasting lipoprotein subclass profile, lipoprotein kinetics, and postprandial fatty acid kinetics. In a randomized double blind cross-over trial, 12 male subjects (age 51±7 years; BMI 28.5±0.8 kg/m2), were divided into 2 groups according to waist-hip ratio. They were supplemented with 60 grams/day MCFA (mainly C8:0, C10:0) or linoleic acid for three weeks, with a wash-out period of six weeks in between. Lipoprotein subclasses were measured using HPLC. Lipoprotein and fatty acid metabolism were studied using a combination of several stable isotope tracers. Lipoprotein and tracer data were analyzed using computational modeling. Lipopro...

Research paper thumbnail of Clustering by Plasma Lipoprotein Profile Reveals Two Distinct Subgroups with Positive Lipid Response to Fenofibrate Therapy

Research paper thumbnail of Hope for Students in an Information Age

Journal of Polian Studies, 2022

In this introduction, I will situate Polo’s article on hope within the context of the project to ... more In this introduction, I will situate Polo’s article on hope within the context of the project to introduce Polo’s thought to English-speaking educational institutions. To this end, my aim is four-fold. First, I will highlight the relevance of Polo’s thought for education. Second, I will relate the article on hope to Polo’s thought more generally. Third, I will provide an overview of the content of the paper. And fourth, I will discuss the significance of this paper for young people in our information age.

Research paper thumbnail of See Profile

Diagnostic markers based on a computational model of lipoprotein metabolism

Research paper thumbnail of Maternal Underestimation of Child’s Weight at Pre-School Age and Weight Development between Age 5 and 12 Years: The ABCD-Study

International Journal of Environmental Research and Public Health, 2020

Background: Healthcare monitoring of child growth reduces with age, which may increase parental i... more Background: Healthcare monitoring of child growth reduces with age, which may increase parental influences on children’s weight development. This study aimed to examine the association between maternal underestimation of child’s weight at age 5/6 and weight development between 5 and 12 years. Methods: We performed univariate and multivariate linear regression analyses with data on maternal perception of child’s weight and weight development (∆SDS body-mass index; BMI) derived from the Amsterdam Born Children and their Development (ABCD) birth-cohort study. Underestimation was defined by comparing maternal perception of child’s weight with the actual weight status of her child. Associations were studied in two groups: children with overweight (n = 207) and children with normal weight (n = 1982) at baseline (children with underweight were excluded). Results: Underestimation was 5.5% in children with normal weight and 79.7% in children with overweight. Univariate analyses in children w...

Research paper thumbnail of Machine learning modelling of blood lipid biomarkers in familial hypercholesterolaemia versus polygenic/environmental dyslipidaemia

Scientific Reports, 2021

Familial hypercholesterolaemia increases circulating LDL-C levels and leads to premature cardiova... more Familial hypercholesterolaemia increases circulating LDL-C levels and leads to premature cardiovascular disease when undiagnosed or untreated. Current guidelines support genetic testing in patients complying with clinical diagnostic criteria and cascade screening of their family members. However, most of hyperlipidaemic subjects do not present pathogenic variants in the known disease genes, and most likely suffer from polygenic hypercholesterolaemia, which translates into a relatively low yield of genetic screening programs. This study aims to identify new biomarkers and develop new approaches to improve the identification of individuals carrying monogenic causative variants. Using a machine-learning approach in a paediatric dataset of individuals, tested for disease causative genes and with an extended lipid profile, we developed new models able to classify familial hypercholesterolaemia patients with a much higher specificity than currently used methods. The best performing models...

Research paper thumbnail of Rank reversals in tree growth along tree size, competition and climatic

gradients for four forest canopy dominant species in Central Spain*

Research paper thumbnail of Rank reversals in tree growth along tree size, competition and climatic gradients for four forest canopy dominant species in Central

Research paper thumbnail of Improved cholesterol phenotype analysis by a model relating lipoprotein life cycle processes to particle size

The Journal of Lipid Research, 2009

Research paper thumbnail of Computational models for analyzing lipoprotein profiles

Clinical Lipidology, 2011

Research paper thumbnail of Rank reversals in tree growth along tree size, competition and climatic gradients for four forest canopy dominant species in Central Spain

Annals of Forest Science, 2008

Research paper thumbnail of Diagnostic markers based on a computational model of lipoprotein metabolism

Journal of clinical bioinformatics, 2011

Dyslipidemia is an important risk factor for cardiovascular disease and type II diabetes. Lipopro... more Dyslipidemia is an important risk factor for cardiovascular disease and type II diabetes. Lipoprotein diagnostics, such as LDL cholesterol and HDL cholesterol, help to diagnose these diseases. Lipoprotein profile measurements could improve lipoprotein diagnostics, but interpretational complexity has limited their clinical application to date. We have previously developed a computational model called Particle Profiler to interpret lipoprotein profiles. In the current study we further developed and calibrated Particle Profiler using subjects with specific genetic conditions. We subsequently performed technical validation and worked at an initial indication of clinical usefulness starting from available data on lipoprotein concentrations and metabolic fluxes. Since the model outcomes cannot be measured directly, the only available technical validation was corroboration. For an initial indication of clinical usefulness, pooled lipoprotein metabolic flux data was available from subjects ...

Research paper thumbnail of Rank reversals in tree growth along tree size, competition and climatic

gradients for four forest canopy dominant species in Central Spain*

Research paper thumbnail of Transcendence and Love for a New Global Society Proceedings of the II International Congress Transcendence and Love for a New Global Society

There is no dispute in neuroscience that structure and function are related, but it is difficult ... more There is no dispute in neuroscience that structure and function are related, but it is difficult to identify how exactly this relationship occurs. The phrenological view advocates for the idea that each area of the brain corresponds to a particular function. This view then evolved into a modular view, meaning that each brain network corresponds to a singular function. But these views have serious limitations and a more systemic one is in order. It is thought that brain function is related to dynamic and temporary neural assemblies. What seems obvious is that the relationship between structure and function is not straightforward. In this article, we will see how the non-function of brain areas and the non-univocal relationship between structure and function can serve as an opportunity to offer a new concept, i.e., “functionalization”, which the philosopher Leonardo Polo proposed. Polo understood functionalization as a part of function. We believe that the presence of this “intermedia...

Research paper thumbnail of Differential associations between psychosocial stress and obesity among Ghanaians in Europe and in Ghana: findings from the RODAM study

Social Psychiatry and Psychiatric Epidemiology

Purpose Psychosocial stress is associated with obesity in some populations, but it is unclear whe... more Purpose Psychosocial stress is associated with obesity in some populations, but it is unclear whether the association is related to migration. This study explored associations between psychosocial stress and obesity among Ghanaian migrants in Europe and non-migrant Ghanaians in Ghana. Methods Cross-sectional data from the RODAM study were used, including 5898 Ghanaians residing in Germany, the UK, the Netherlands, rural Ghana, and urban Ghana. Perceived discrimination, negative life events and stress at work or at home were examined in relation to body mass index (BMI) and waist circumference (WC). Linear regression analyses were performed separately for migrants and non-migrants stratified by sex. Results Perceived discrimination was not associated with BMI and WC in both migrants and non-migrants. However, negative life events were positively associated with BMI (β = 0.78, 95% CI 0.34-1.22) and WC (β = 1.96, 95% CI 0.79-3.12) among male Ghanaian migrants. Similarly, stress at work or at home was positively associated with BMI (β = 0.28, 95% CI 0.00-0.56) and WC (β = 0.84, 95% CI 0.05-1.63) among male Ghanaian migrants. Among non-migrant Ghanaians, in contrast, stress at work or at home was inversely associated with BMI and WC in both males (β = − 0.66, 95% CI − 1.03 to − 0.28; β = − 1.71 95% CI − 2.69 to − 0.73, respectively) and females (β = − 0.81, 95% CI − 1.20 to − 0.42; β = − 1.46, 95% CI − 2.30 to − 0.61, respectively). Conclusions Negative life events and stress at work or at home are associated with increased body weight among male Ghanaians in European settings, whereas stress at work or at home is associated with reduced body weight among Ghanaians in Ghana. More work is needed to understand the underlying factors driving these differential associations to assist prevention efforts.

Research paper thumbnail of Effect of body fat distribution on the physiological response to a dietary fat intervention

The Faseb Journal, Apr 1, 2009

Research paper thumbnail of The effect of plant sterols and different low doses of omega-3 fatty acids from fish oil on lipoprotein subclasses

Molecular Nutrition & Food Research, 2015

Consumption of a low-fat spread enriched with plant sterols (PS) and different low doses (&am... more Consumption of a low-fat spread enriched with plant sterols (PS) and different low doses (<2 g/day) of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil reduces serum triglycerides (TGs) and low-density lipoprotein-cholesterol (LDL-Chol) and thus beneficially affects two blood lipid risk factors. Yet, their combined effects on TG and Chol in various lipoprotein subclasses have been investigated to a limited extent. In a randomized, double-blind, placebo-controlled, parallel study, we determined TG and Chol in 13 LP subclasses in fasting serum of 282 hypercholesterolemic subjects, who consumed either a placebo spread or one of the four spreads containing PS (2.5 g/day) and EPA+DHA (0.0, 0.9, 1.3, and 1.8 g/day) for 4 weeks. After PS treatment, total LDL-Chol was reduced, which was not further changed by EPA+DHA. No shift in the LDL-Chol particle distribution was observed. The addition of EPA+DHA to PS dose-dependently reduced VLDL-Chol and VLDL-TG mainly in larger particles. Furthermore, the two highest doses of EPA+DHA increased Chol and TG in the larger HDL particles, while these concentrations were decreased in the smallest HDL particles. The consumption of a low-fat spread enriched with both PS and EPA+DHA induced shifts in the lipoprotein distribution that may provide additional cardiovascular benefits over PS consumption alone.

Research paper thumbnail of Candidate Diagnostics Indicating Lipoprotein Metabolism Status from a Single Blood Sample

Research paper thumbnail of MS327 Clustering by Plasma Lipoprotein Profile Reveals Large Fenofibrate Responder Subgroup

Atherosclerosis Supplements, 2010

Research paper thumbnail of Abstract: P934 DEVELOPING A MATHEMATICAL MODEL TO DETERMINE THE RATES OF LIPOPROTEIN METABOLIC PROCESSES FROM A SINGLE PLASMA SAMPLE

Atherosclerosis Supplements, 2009

Research paper thumbnail of Dietary medium chain fatty acid supplementation leads to reduced VLDL lipolysis and uptake rates in comparison to linoleic acid supplementation

PloS one, 2014

Dietary medium chain fatty acids (MCFA) and linoleic acid follow different metabolic routes, and ... more Dietary medium chain fatty acids (MCFA) and linoleic acid follow different metabolic routes, and linoleic acid activates PPAR receptors. Both these mechanisms may modify lipoprotein and fatty acid metabolism after dietary intervention. Our objective was to investigate how dietary MCFA and linoleic acid supplementation and body fat distribution affect the fasting lipoprotein subclass profile, lipoprotein kinetics, and postprandial fatty acid kinetics. In a randomized double blind cross-over trial, 12 male subjects (age 51±7 years; BMI 28.5±0.8 kg/m2), were divided into 2 groups according to waist-hip ratio. They were supplemented with 60 grams/day MCFA (mainly C8:0, C10:0) or linoleic acid for three weeks, with a wash-out period of six weeks in between. Lipoprotein subclasses were measured using HPLC. Lipoprotein and fatty acid metabolism were studied using a combination of several stable isotope tracers. Lipoprotein and tracer data were analyzed using computational modeling. Lipopro...

Research paper thumbnail of Clustering by Plasma Lipoprotein Profile Reveals Two Distinct Subgroups with Positive Lipid Response to Fenofibrate Therapy