In a recent meta-analysis, we showed that individuals with inflammatory bowel disease (IBD) (i.g., Crohn's disease and ulcerative colitis) report poorer sleep quality compared to healthy individuals. In the present study, we aim to better define the role of insomnia (e.g., persistent difficulties falling asleep or maintain sleep) in the clinical manifestations of IBD. Epidemiological data estimate the prevalence of insomnia disorder from 6 to 20% in industrialised societies, with rates varying depending on country under study and methodological quality. While it is well-known that insomnia and other sleep problems (e.g., short sleep duration, poor sleep quality) can impact the immune function and inflammation, the role of insomnia in inflammatory bowel disease (IBD) is unclear. Sleep duration and quality have key consequences for proinflammatory cytokines expression, which are considered mediators of inflammatory processes. For instance, individuals with insomnia show elevated levels of daytime IL-6 and TNF-a compared to good sleepers. Also, nocturnal levels of IL-6 are associated with perceived sleep quality and slow wave sleep. However, whether insomnia affects activity disease in IBD is still unclear. The aim of the study is to longitudinally explore the possibility that insomnia symptoms may be associated with worse objectively assessed IBD activity. The study will be conducted in collaboration with the U.O.C for "Malattie dell'apparato digerente e del fegato", Azienda Ospedaliera S. Andrea, Sapienza Università di Rome. Fifty participants with either Crohn's disease of ulcerative colitis will be recruited. Participants will complete a full physical and psychological assessment including measures of insomnia and IBD activity severity at baseline and at 6 months follow up.
Insomnia disorder is the most common sleep disorder worldwide (American Psychiatric Association, 2013), and it is associated with a wide range of negative outcomes including reduced quality of life (Kyle, Morgan, & Espie, 2010; LeBlanc et al., 2007; Léger et al., 2012), increased risk of developing cardiovascular diseases (Sofi et al., 2014) as well as psychiatric disorders, especially depression and anxiety disorders (Baglioni et al., 2011; Hertenstein et al., 2019). The role of insomnia in inflammatory diseases, and specifically inflammatory bowel disease (IBD) is, however, unclear. Whilst it is well-known that sleep duration and quality have key consequences for proinflammatory cytokines expression, which are considered mediators of inflammatory processes, less is known about the specific influence of insomnia on IBD. Individuals with insomnia show elevated levels of daytime IL-6 and TNF-a compared to good sleepers (Vgontzas et al. 2002). Moreover, cross-sectional evidence showed that when comparing individuals with IBD reporting poor sleep quality/insomnia to individuals with IBD reporting good sleep on activity disease indicators, the first group generally show worse activity disease (e.g., Ballesio et al., 2021; Abdalla et al. 2017; Habibi et al. 2019). In order to progress the knowledge in this field, longitudinal studies are utmost warranted. Previous longitudinal studies in fact have mostly focused on the broad concept of sleep quality or sleep duration, and largely neglected an assessment of insomnia. In this context, Tauseef et al. (2013) found that clinically poor sleep quality predicted active IBD symptoms. Moreover, in a large study conducted in women in the UK, those reporting sleep duration