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.
Study Type
OBSERVATIONAL
Enrollment
38
Lausanne University Hospital (CHUV)
Lausanne, Switzerland
Eating duration
Duration from the first to last caloric intake over 24-hour cycle
Time frame: 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
Time frame: At baseline
Sleep/wake cycles
Measured by actigraphy
Time frame: 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)
Time frame: Changes between baseline and the close-out visit (i.e. changes between Month 0 and Month 6)
Body weight
Measured by bioelectrical impedance analysis
Time frame: Changes between baseline and the close-out visit (i.e. changes between Month 0 and Month 6)
Fat mass
Measured by bioelectrical impedance analysis
Time frame: 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
Time frame: 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
Time frame: Changes between baseline and the close-out visit (i.e. changes between Month 0 and Month 6)
Fasting glucose
Measured by clinical chemistry
Time frame: 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
Time frame: 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
Time frame: Changes between baseline and the close-out visit (i.e. changes between Month 0 and Month 6)
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