The aim of this study is to investigate the effects of genetic and environmental risk factors on central nervous system (CNS) reward and satiety circuits in the etiology of obesity. The investigators will also investigate to what extent the alterations in CNS reward and satiety circuits are a cause or a consequence of the development of obesity.
Study Type
OBSERVATIONAL
Enrollment
92
VU University Medical Center
Amsterdam, Netherlands
The difference in neuronal activity in CNS reward and satiety circuits as represented by BOLD functional magnetic resonance imaging (fMRI) signal change from baseline (%) in response to food-related stimuli within obesity discordant MZ twin pairs.
Time frame: Baseline (one measurement)
The difference in neuronal activity in CNS reward and satiety circuits as represented by BOLD fMRI signal change from baseline (%) in response to food-related stimuli between individuals at high verses low genetic obesity risk.
Time frame: Baseline (one measurement)
The difference in neuronal activity in CNS reward and satiety circuits as represented by BOLD fMRI signal change from baseline (%) in response to food-related stimuli between lean and obese subjects with either high or low genetic obesity risk.
Time frame: Baseline (one measurement)
The difference within obesity-discordant monozygotic (MZ) twin pairs regarding dietary intake
Dietary intake will be measured as quantitative (kcal/day) and qualitative (energy density (kcal/kg) and macronutrient composition (%)) dietary intake using A) a choice lunch buffet on the visit day and B) the 24 hours recall method on two week days and one weekend day at home.
Time frame: Baseline (one measurement)
The difference within obesity-discordant monozygotic (MZ) twin pairs regarding physical activity level
Physical activity level will be measured as metabolic equivalent of task (METs)-hours per week using seven-day ActiGraph triaxial accelerometry at home.
Time frame: Baseline (one measurement)
The difference within obesity-discordant monozygotic (MZ) twin pairs regarding basal metabolic rate
Basal metabolic rate will be measured in kcal/day using oxygen consumption and carbon dioxide production measured by indirect calorimetry using a ventilated hood system.
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Time frame: Baseline (one measurement)
The difference within obesity-discordant monozygotic (MZ) twin pairs regarding fasting circulating biomarker levels
Fasting circulating biomarker levels (glucose (mmol/l), HbA1c (mmol/mol), insulin (pmol/l), C-peptide (nmol/l), glucagon (pmol/l), triglycerides (mmol/l), HDL-cholesterol (mmol/l) and LDL-cholesterol (mmol/l)) will be measured in a fasting blood sample.
Time frame: Baseline (one measurement)
The difference within obesity-discordant monozygotic (MZ) twin pairs regarding autonomic nervous system balance
Autonomic nervous system balance will be assessment based on measurements of A) heart rate variability (HRV; calculated as root mean square of successive R-R interval differences (RMSSD) in ms2); B) respiratory rate (RR; breaths/min) and C) respiratory sinus arrhythmia (RSA; ms) in resting conditions and in response to a mental arithmetic task using an electro- and impedance cardiogram.
Time frame: Baseline (one measurement)
The difference between individuals at high versus those at low genetic obesity risk regarding dietary intake
Dietary intake will be measured as quantitative (kcal/day) and qualitative (energy density (kcal/kg) and macronutrient composition (%)) dietary intake using A) a choice lunch buffet on the visit day and B) the 24 hours recall method on two week days and one weekend day at home.
Time frame: Baseline (one measurement)
The difference between individuals at high versus those at low genetic obesity risk regarding physical activity level
Physical activity level will be measured as metabolic equivalent of task (METs)-hours per week using seven-day ActiGraph triaxial accelerometry at home.
Time frame: Baseline (one measurement)
The difference between individuals at high versus those at low genetic obesity risk regarding basal metabolic rate
Basal metabolic rate will be measured in kcal/day using oxygen consumption and carbon dioxide production measured by indirect calorimetry using a ventilated hood system.
Time frame: Baseline (one measurement)
The difference between individuals at high versus those at low genetic obesity risk regarding fasting circulating biomarker levels
Fasting circulating biomarker levels (glucose (mmol/l), HbA1c (mmol/mol), insulin (pmol/l), C-peptide (nmol/l), glucagon (pmol/l), triglycerides (mmol/l), HDL-cholesterol (mmol/l) and LDL-cholesterol (mmol/l)) will be measured in a fasting blood sample.
Time frame: Baseline (one measurement)
The difference between individuals at high versus those at low genetic obesity risk regarding autonomic nervous system balance
Autonomic nervous system balance will be assessment based on measurements of A) heart rate variability (HRV; calculated as root mean square of successive R-R interval differences (RMSSD) in ms2); B) respiratory rate (RR; breaths/min) and C) respiratory sinus arrhythmia (RSA; ms) in resting conditions and in response to a mental arithmetic task using an electro- and impedance cardiogram.
Time frame: Baseline (one measurement)