Overview
The hypothesis is that menstrual cyclicity affects glucose and energy metabolism in women with type 1 diabetes. The rationale of the hypothesis on cycle effects builds on the assumption that fluctuations of female sex hormones across the menstrual cycle cause changes in physiological parameters of glucose metabolism and energy homeostasis and/or lifestyle aspects involved in the regulation of blood glucose and body weight. It is expected that hormone fluctuations affect insulin sensitivity, gastric emptying, eating behaviour and energy expenditure. It is anticipated that insulin sensitivity is highest in the pre-ovulatory phase and lowest in the mid-luteal phase. It is further expected that gastric emptying peaks in the follicular phase, and highest energy expenditure and dietary intake during the mid-luteal phase.
The primary objective of this study is to characterize glucose and energy metabolism throughout the menstrual cycle in natural cycling women with type 1 diabetes. Further objectives are to assess the impact of the menstrual cycle on glucose control and insulin requirements, investigate how fluctuations in sex hormone levels influence glucose and energy metabolism, and quantify both inter- and intra-individual variability in metabolic changes related to the menstrual cycle. Additionally, the study will evaluate whether changes in key physiological components of glucose metabolism and behavioural factors mediate menstrual cycle-related variations in glucose control and insulin requirements.
Eligibility
Inclusion Criteria:
- Female sex assigned at birth
- Type 1 diabetes for at least 12 months
- Aged 18-45 years
- Natural menstrual cycle (occurring without medical or hormonal interventions)
- Functional insulin therapy delivered via injection or insulin pump
- Willingness to follow study-related procedures
- Willingness to use mechanical contraception during the time of study participation
Exclusion Criteria:
- Use of contraceptives or medical interventions that interfere with natural hormonal fluctuations of the menstrual cycle or cyclical bleeding
- Interventions interfering with glucose or energy metabolism (other than insulin, thyroid hormone replacement or statins), as judged by the investigator, will be paused for the duration of the study, with an adequate washout duration prior to the start of data collection
- Presence of any physical or psychological condition, or any medical intervention likely to interfere with the conduct of the procedures and/or their evaluation, as judged by the investigator
- Pregnant or breast-feeding
- Participation in another clinical study that interferes with the interpretation of the study results as judged by the investigator
