Circadian Clocks and Eating Patterns (Cohort)

Study Overview
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Brief Summary
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For women of reproductive age, the overall postpartum weight retention (weight gain between pregnancies) plays a significant role in long-term obesity. With 20% of women retaining ≥ 5 kg at 12 months postpartum, the risk of developing conditions, such as gestational diabetes mellitus (GDM), metabolic syndrome (MS) and subsequently diabetes and cardiovascular diseases, is substantially increased. In post-GDM mothers (women who had GDM in their recent pregnancy), postpartum weight retention is also an essential predictor of future diabetes. Recent studies have identified the impact of circadian rhythms (influencing sleep/wake cycles) and diurnal rhythm of eating (when and how often calories are consumed over a 24h period) on cardio-metabolic disorders. In women, one remarkable feature of the postpartum period is an 'externally imposed' circadian misalignment of both sleep and eating rhythms, because most babies take several weeks to months to establish their daily pattern of activity and feeding, which is particularly relevant for breastfeeding women, as the responsibility is generally on the mother. The overarching goal of this project is to explore the interplay between the diurnal rhythm of eating, circadian and metabolic parameters in humans. The potential postpartum effects of circadian disruption will be unraveled in women who had GDM during their pregnancy and those with an uneventful pregnancy. These women are subject to a circadian misalignment due to their 'externally imposed' changes in sleep/wake cycles and eating times in the postpartum period. With a comprehensive approach combining molecular characterization of in vivo and in vitro circadian clock parameters along with metabolic, endocrine, transcriptomic, and lipidomic studies, the investigators will assess if eating duration and/or circadian misalignment impact on circadian clock parameters of postpartum women in a prospective cohort of 6 months.

Official Title
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Molecular and Functional Interplay Between the Circadian Clocks and Eating Patterns in Patients With Cardio-metabolic Diseases (Cohort)

Conditions
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Postpartum Women, Diabetes, Gestational

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18-40 years Breastfeeding mothers at 4-8 week postpartum With or without gestational diabetes mellitus diagnosed at 24-32 gestational weeks, according to the International Association of Diabetes and Pregnancy Study Groups (IADPSG) consensus criteria Confident use of a smartphone and able to take regular pictures of food/drinks Exclusion Criteria: Pre-existing diabetes (prior to pregnancy) Major illness/fever over the 2 weeks (prior to the visits with blood tests) Shift work or work at irregular hours planned after maternity leave Active cancer and/or oncologic treatment over the previous 12 months Coagulation disorder, on regular anticoagulant drug, skin disorder affecting wound healing Enrolled in a clinical trial / intervention study Major known mental illness, unable to give informed consent Inability to follow the study procedures

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Postpartum women who had gestational diabetes mellitus<br>Inclusion at 4-8 weeks postpartum Follow-up for 6 months | |
| Postpartum women after an uneventful pregnancy<br>Inclusion at 4-8 weeks postpartum Follow-up for 6 months | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Eating duration | Duration from the first to last caloric intake over 24-hour cycle | Changes between baseline and the close-out visit (i.e. changes between Month 0 and Month 6) | 
| Correlation of in vitro circadian parameters (amplitude and magnitude) with clinical metabolic health outcomes (body weight) | Measured in cultured skin fibroblasts | At baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sleep/wake cycles | Measured by actigraphy | Changes between baseline and the close-out visit (i.e. changes between Month 0 and Month 6) | 
| Sleep/wake cycles | Measured by the Pittsburgh Sleep Quality Index (scale 0-21, 0 indicating no sleeping difficulty, 21 indicating severe sleeping difficulties) | Changes between baseline and the close-out visit (i.e. changes between Month 0 and Month 6) | 
| Body weight | Measured by bioelectrical impedance analysis | Changes between baseline and the close-out visit (i.e. changes between Month 0 and Month 6) | 
| Fat mass | Measured by bioelectrical impedance analysis | Changes between baseline and the close-out visit (i.e.changes between Month 0 and Month 6) | 
| Fat-free mass | Measured by bioelectrical impedance analysis | Changes between baseline and the close-out visit (i.e. changes between Month 0 and Month 6) | 
| Physical activity (activity count per minute) | Measured by actigraphy | Changes between baseline and the close-out visit (i.e. changes between Month 0 and Month 6) | 
| Fasting glucose | Measured by clinical chemistry | Changes between baseline and the close-out visit (i.e. changes between Month 0 and Month 6) | 
| Lipid profile (concentration of total cholesterol, LDL cholesterol, triglycerides, HDL cholesterol) | Measured by clinical chemistry | Changes between baseline and the close-out visit (i.e. changes between Month 0 and Month 6) | 
| Glucose excursion (time-in-range, coefficient of variation) | Measured by continuous glucose monitoring | Changes between baseline and the close-out visit (i.e. changes between Month 0 and Month 6) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Circadian rhythms, Metabolic syndrome, Eating duration, Sleep/wake cycles