Obstructive sleep apnea negatively affects cognition in women with multiple sclerosis
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Key takeaways:
- Sleep disorders were more common in women with vs. without multiple sclerosis.
- Obstructive sleep apnea had the largest effect on cognition in interaction analyses.
Obstructive sleep apnea had a significant effect on perceived problems with cognitive function in women with multiple sclerosis, according to study results published in Multiple Sclerosis Journal.
“Our findings provide new evidence to suggest that sleep disorders may play a pivotal role in the development of cognitive problems in women with multiple sclerosis [MS],” Tiffany J. Braley, MD, MS, director of the division of multiple sclerosis and neuroimmunology at Michigan Medicine, University of Michigan, told Healio. “As interventions to delay cognitive decline in MS may be of highest yield in pre-symptomatic or early symptomatic stages, timely treatment of sleep disorders could offer a potential preventative approach to cognitive decline in MS. More research is needed to determine the scope and cognitive impact of sleep disorders in people with MS to shape clinical guidelines.”
Braley and colleagues analyzed 63,866 women (mean age, 58.7 years; 95.3% white) from the 2013 and 2017 waves of the Nurses’ Health Study (a longitudinal cohort study of women nurses) to understand how OSA, sleepiness and insomnia are each related to reported reductions in cognition in women with MS.
By using items in a survey that assess nurses’ memory and ability to follow instructions, conversations/plots and street navigation, researchers assessed subjective cognition.
Researchers then utilized a statistical method known as the “decomposition method” that measures four effects — controlled direct, reference interaction, mediated interactions and pure indirect — to estimate the effects of diagnosed or suspected sleep disorders on the relationship between MS and cognitive function.
Of the total cohort, 524 women had MS. In 2013, researchers observed more women with MS experienced OSA, sleepiness and insomnia, and in 2017, they described more cognitive issues in those women with vs. without MS.
Before evaluating how each sleep disorder affected cognitive function, researchers looked at how MS was related to cognitive function and found that it was linked to high odds for trouble following verbal instructions (adjusted OR = 2.2; 95% CI, 1.6-3), trouble following conversations/plots (aOR = 1.9; 95% CI, 1.3-2.9), trouble with street navigation (aOR = 2.7; CI 1.5-4.9) and memory difficulty (beta = 0.24; 95% CI, 0.14-0.34) compared with no MS.
Notably, in women with MS, each sleep disorder showed different levels of effects on cognitive function. Researchers observed that mediation and/or interaction with OSA in women with MS demonstrated increased odds for cognitive impairment in terms of following instructions (aOR = 2.2; 95% CI, 1.5-2.9), following conversations/plots (aOR = 1.9; 95% CI, 1.2-2.7) and following street navigation (aOR = 2.8, 95% CI, 1.1-4.4).
Looking specifically at the following instructions outcome in relation to MS, researchers observed that 33.5% (95% CI, 0.1-66.9) of the total interaction was due to OSA.
When assessing the effect insomnia has on cognition in women with MS, researchers found that the pure indirect effect mediated 5.4% (95% CI, 1.3-9.5) of the total effect on following instructions, 8.4% (95% CI, 5.7-16.1) of the total effect on following conversations/plots and 15.1% of the total effect on memory problems.
Comparable findings in terms of pure indirect effect were observed when looking at the effect sleepiness has on cognition in women with MS. This effect mediated 8.6% of the total effect on the following instructions outcome, 10.1% of the total effect on the following conversations/plots outcome and 12.3% of the total effect on memory weakening.
“We expected to see that reported sleep disorders would be associated with reports of future cognitive problems in women with MS, but we did not expect that the pathways by which sleep disorders exerted their effects on future cognitive problems in MS would vary based on the type of sleep disorder experienced,” Braley told Healio.
“Studies that span longer timeframes and include both objective and self-reported cognitive outcomes, as well as objective sleep data, are still needed to fully characterize the relationship between MS, sleep disorders and cognitive dysfunction,” Braley added.
For more information:
Tiffany J. Braley, MD, can be reached at tbraley@med.umich.edu.
Reference:
- Insomnia, sleep apnea contribute to reports of cognitive decline in women with multiple sclerosis. https://www.michiganmedicine.org/health-lab/insomnia-sleep-apnea-contribute-reports-cognitive-decline-women-multiple-sclerosis. Published March 15, 2023. Accessed March 23, 2023.