Although rheumatoid arthritis (RA) patients and those with severe seasonal allergy appear to have insomnia, inflammation may not be an independent predictor of insomnia, according to a study published in Nature and Science of Sleep.
An exploratory study was conducted in Sweden to investigate objective and subjective sleep disorders in people with allergy and RA and the effect of sleep measures on markers of inflammation.
Researchers used sleep diaries, single-channel electroencephalography (EEG), and actigraphy to assess study participants’ sleep. Researchers also evaluated whether sleep measures were linked to central immune activation by using positron emission tomography (PET) of the translocator protein (TSPO) along with cytokine markers for peripheral inflammation, disease-specific symptoms, and general disease symptoms.
The study included a total of 18 people with seasonal pollen allergy, 18 patients with RA and 26 healthy control participants. Data from patients with allergies and matched controls were evaluated twice, both within and outside of the pollen season; Data from patients with RA were evaluated once. Sleep was also recorded for about 1 week each time.
The results of the study showed that people with seasonal allergies had a shorter total sleep time (TST) compared to healthy participants according to the EEG measurements over the seasons. People with allergies also showed an increase in the percentage of slow wave sleep (SWS) during the pollen season. Patients with allergy vs. control participants had poorer sleep quality during the pollen season. In addition, morning sleepiness was increased in people with allergies during the pollen season.
Based on sleep diaries, TST did not differ between groups. In addition, patients with allergies after the decomposition showed a significant increase in the absolute SWS time during the pollen season (+8.79 min; P = 0.01), while this was not the case with the control participants (-2.42 min; P = 0.34).
The TST did not differ between patients with RA and control participants, according to sleep diaries and the EEG. Patients with RA vs. control participants had significantly shorter sleep, but no deep sleep, light sleep, and rapid eye movement sleep. No significant differences between the groups in terms of sleep efficiency or the number of awakenings were observed.
Compared to control participants, patients with allergies did not have significantly higher disease symptoms (P = .970), and the interaction with the pollen season was not significant (P = .089). However, patients with RA reported significantly higher disease symptoms compared to controls (P = 0.008). In addition, no significant associations were observed between disease symptoms and TST, the amount of deep sleep, or the subjective sleep quality.
In all groups, proinflammatory cytokines, gray matter TSPO levels, and general disease symptoms were not associated with objective or subjective sleep measurements. Rhinitis, but not conjunctivitis, was associated with poorer subjective sleep and more SWS in persons with seasonal allergies. In patients with RA, functional status, but not disease activity, was predictive of lower subjective sleep.
The main limitation of the study was the relatively small sample size.
The researchers concluded, “This study confirms previous results that both seasonal allergy patients and RA suffer from insomnia in addition to their primary symptoms.”
Disclosure: Some of the study authors stated links with biotech, pharmaceutical, and / or device companies. For a full list of specifications, see the original reference.
Tamm S., Lensmar C., Andreasson A. et al. Objective and subjective sleep in rheumatoid arthritis and severe seasonal allergy: preliminary assessments of the role of disease, central and peripheral inflammation. Nat Sci sleep. 2021; 13: 775-789. doi: 10.2147 / NSS.S297702
This article originally appeared on Rheumatology Advisor