Cortisol dynamics and sleep quality: the role of sex and oral contraceptive use 105 1. Introduction There is a well-known sex difference in sleep quality: women report poorer sleep (Li et al., 2019) and are 1.5 times more likely to report insomnia than men (Zhang & Wing, 2006). Women report poorer subjective sleep efficiency, more sleep disturbances and more frequent use of sleep medication than men (Li et al., 2019). Multiple factors can contribute to sex differences in sleep quality, including changes in sex steroids (Morssinkhof et al., 2020). Examples of this are seen in the menstrual cycle, when women report poorer sleep in the luteal phase (Işik et al., 2022), and in the menopausal transition, where many women report an increase of disrupted sleep (Blümel et al., 2012). Previous studies have also found possible effects of oral contraceptive (OC) use on sleep quality in women. A large cohort study in a community sample found higher insomnia symptom scores in OC users compared to non-users, although the identified differences were small (Bezerra et al., 2020). Similarly, a prospective study in a community sample showed that sleep quality modestly decreased after starting OCs compared to those not starting OCs, with the most prominent effects seen in reduced sleep duration, increased sleep disruptions and more frequent use of sleeping medication (Albuquerque et al., 2015). However, a meta-analysis reported mixed findings in the assessment of subjective sleep in OC users compared to non-users. Notably, this meta-analysis excluded studies which included women with mood disorders (Bezerra et al., 2023). Recent work of ours in a large cross-sectional database, enriched with a large sample of women with a history of depression or anxiety, showed that women using OCs reported more insomnia symptoms than naturally cycling (NC) women (Morssinkhof et al., 2021). In this study, OC users showed significantly more sleep disruptions during the night and early in the morning, which suggests that OCs could affect sleep quality and specifically sleep disruptions. Further replication is needed to determine if so and for which groups of women this may apply. There are indications that cortisol dynamics are altered in men and women with insomnia (Dressle et al., 2022). In healthy persons, cortisol serum levels show a diurnal rhythm which is regulated by the hypothalamic-pituitaryadrenal (HPA) axis. As part of this diurnal rhythm, at awakening, cortisol
RkJQdWJsaXNoZXIy MTk4NDMw