Chronobiology and Childhood Obesity in a Mediterranean Spanish Population

Study Overview
=================
Brief Summary
-----------------
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.

Detailed Description
-----------------
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.

Official Title
-----------------
Chronobiology and Childhood Obesity in a Mediterranean Spanish Population (ONTIME-JR: Obesity, Nutrigenomics, Timing, Mediterranean, Junior)

Conditions
-----------------
Obesity, Chronobiology Disorders

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age: 8-12 years of age Children from schools in the region of Murcia (Spain) who enter voluntarily Exclusion Criteria: Children who take melatonin or sleep drugs

Ages Eligible for Study
-----------------
Minimum Age: 8 Years
Maximum Age: 12 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------
What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | At baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | 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. | 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. | 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. | 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. | 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. | 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. | At baseline | 
| Total energy intake | During the week of the experiment with a software designed for this purpose. | At baseline | 
| Macronutrient distribution | from the 7 days dietary record, with a software designed for this purpose. | At baseline | 
| Food variety | from the 7 days dietary record, with a software designed for this purpose. | At baseline | 
| Glycemic Index | from the 7 days dietary record, with a software designed for this purpose. | At baseline | 
| Physical activity | from the 7 days dietary record, with a software designed for this purpose. | Through study completion | 
| Mediterranean Diet Score | From the 7 days dietary record, with a software designed for this purpose. | 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). | At baseline | 
| Light determination | During the week of the experiment with a light detector device in the neck of the children. | At baseline | 
| DNA collection in saliva | Saliva will be collected to further extraction of DNA the 7th day of the experimental week. | At baseline | 
| Saliva collection for microflora determinations | Saliva Collection Method is the SalivaBio Oral Swab the 7th day of the experimental week. | At baseline | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Obesity, Chronobiology, Circadian