The main objective is to investigate chronobiological aspects of childhood obesity studying the potential relationship between meal patterns and circadian rhythmicity in a cross-sectional sample of obese, overweight and normal weight children/adolescent.
Childhood obesity has more than doubled in children and tripled in adolescents in the past 30 y. As consequence, increasingly children and adolescents suffer from elevated blood pressure, impaired glucose tolerance, hyperinsulinemia, dyslipidemia. Obesity has a multifactorial etiology since there are potentially numerous contributors to its development and progression. Chronobiology, the science that studies periodic (cyclic) changes in living organisms, has been recently proposed as a new and promising topic to investigate. Alterations of circadian (24 h oscillations) system may contribute to obesity and its complications development such as high blood pressure, insulin resistance, altered fasting lipid profile. Conversely, in a vicious manner, obesity has been regarded as a fault in the circadian system explainable by the association with imbalances and fluctuations of hormones/genes expressions rhythms under the influence of body weight changes. Thus, the study will examine changes in circadian rhythmicity over a week period. The primary end point will be to evaluate differences between obese/overweight and non-obese children in chronotypes and the responses of these parameters to meal patterns. In particular, non-invasive measures that are well-established determinants of chronotypes will form the core endpoints for the study. Well designed and age-appropriate questionnaires will provide further information in order to study correlations with eating, sleeping and sedentary/active behaviors.
Study Type
OBSERVATIONAL
Enrollment
500
Chronobiology laboratory, Department of Physiology
Murcia, Spain
University of Murcia
Murcia, Spain
BMI
A key index for relating weight to height. BMI is a person's weight in kilograms (kg) divided by his or her height in meters squared.
Time frame: At baseline
Individual chronotype with the Munich ChronoType Questionnaire
To assess chronotype with a questionnaire that establishes an algorithm which optimises chronotype assessment by incorporating the information on timing of sleep and wakefulness for both work and free days. The timing and duration of sleep are generally independent. However, when the two are analysed separately for work and free days, sleep duration strongly depends on chronotype. In addition, chronotype is both age- and sex-dependent.
Time frame: At baseline
Wrist temperature rhythm
Wrist temperature wireless recording is considered a reliable procedure to evaluate circadian rhythmicity, and an index to establish and follow the effects of chronotherapy in normal living subjects.
Time frame: At baseline
Rest-activity rhythm
Rest-activity rhythm as assessed using a acceleration data logger UA-004-64 (Onset Computer, Bourne, MA, USA) placed on the non-dominant arm by means of a sports band, with its x axis parallel to the humerus bone. The sensor is programmed to record data every 30 s.
Time frame: At baseline
Sleeping characteristics with a 7 days dietary record of night time and day time (siesta) information
24hs record of sleep will be completed during the 7 days of the experiment. Children are instructed to keep a sleep and food diary designed by the University of Murcia Chronobiology Laboratory. The following data will be obtained for every subject on a daily basis: time to bed, time of lights off, nocturnal awakenings lasting more than 10 minutes, sleep offset, the time the participant arose.
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Time frame: At baseline
Salivary cortisol determinations
Saliva for cortisol measurements is obtained before breakfast (09:00 h), lunch time (14:00 h), and bedtime (23:00 h) the 6th the 7th day of the experimental week using the Salivette system. Cortisol is measured with radioimmunoassay.
Time frame: At baseline
Salivary melatonin determinations on weekends the 6th and 7th day of the experimental week
Samples for the measurement of salivary melatonin are obtained before lunch (14:00 h) and at night (1:00 h) the 6th and 7th day of the experimental week.
Time frame: At baseline
Food habits with a 7 days dietary record
During the week of the experiment. Data will be obtained for every subject on a daily basis and they will record the variety of foods that they eat with the portion size.
Time frame: At baseline
Total energy intake
During the week of the experiment with a software designed for this purpose.
Time frame: At baseline
Macronutrient distribution
from the 7 days dietary record, with a software designed for this purpose.
Time frame: At baseline
Food variety
from the 7 days dietary record, with a software designed for this purpose.
Time frame: At baseline
Glycemic Index
from the 7 days dietary record, with a software designed for this purpose.
Time frame: At baseline
Physical activity
from the 7 days dietary record, with a software designed for this purpose.
Time frame: Through study completion
Mediterranean Diet Score
From the 7 days dietary record, with a software designed for this purpose.
Time frame: At baseline
Food timing with a 7 days dietary record
Children will be instructed to keep a food diary. Data will be obtained for every subject on a daily basis and they will record the time of the three main meals (breakfast, lunch, and dinner).
Time frame: At baseline
Light determination
During the week of the experiment with a light detector device in the neck of the children.
Time frame: At baseline
DNA collection in saliva
Saliva will be collected to further extraction of DNA the 7th day of the experimental week.
Time frame: At baseline
Saliva collection for microflora determinations
Saliva Collection Method is the SalivaBio Oral Swab the 7th day of the experimental week.
Time frame: At baseline