Reporting in Neurology, researchers from Monash University in Melbourne, Australia, reveal a compelling link between very irregular sleep patterns and an elevated risk of dementia.
“Sleep health recommendations often focus on getting the recommended amount of sleep, which is seven to nine hours a night, but there is less emphasis on maintaining regular sleep schedules. Our findings suggest the regularity of a person’s sleep is an important factor when considering a person’s risk of dementia,” said Matthew Paul Pase, PhD, associate professor of neurology and epidemiology at Monash University and lead author of the study.
The study involved an extensive cohort of nearly 90, 000 participants in the United Kingdom, with an average age of 62, monitored over an average period of seven years. Researchers used wrist devices worn by the participants for seven days to measure their sleep cycles accurately. The key metric employed was the sleep regularity index, ranging from 0 to 100. A perfect score of 100 indicated consistent sleep and wake times, while a score of 0 reflected highly irregular sleep patterns.
According to the researchers, the results demonstrated a clear correlation between sleep regularity scores and the risk of dementia. Participants in the lowest fifth percentile, meaning those with the most irregular sleep, had an average score of 41. In contrast, those in the highest 95th percentile, with the most regular sleep patterns, boasted an average score of 71. The middle group, falling between these extremes, had an average sleep regularity score of 60.
Even after adjusting for variables such as age, sex, and genetic risk of Alzheimer’s disease, the research team found a significant association between very irregular sleep and dementia risk. Individuals with the most irregular sleep were 53 percent more likely to develop dementia than those in the middle group. Strikingly, individuals with the most regular sleep did not exhibit a lower risk of dementia compared to their counterparts in the middle group.
Pase highlighted the potential for effective sleep health education and behavioral therapies to mitigate irregular sleep patterns. Encouragingly, the study suggests that individuals with irregular sleep may only need to improve their sleep regularity to average levels, rather than exceptionally high levels, to reduce their risk of dementia. However, Pase also emphasized the need for future research to validate these findings and explore potential unknown factors influencing the association between sleep regularity and dementia.
Although the study establishes an association rather than causation, it sheds light on the potential impact of sleep regularity on cognitive health. As the scientific community delves deeper into the complex relationship between sleep patterns and dementia, these findings may pave the way for targeted interventions to promote healthier sleep habits and potentially reduce the risk of dementia in vulnerable populations.
