Research News: Poor sleep linked to multiple chronic conditions

a woman asleep in bed

By Crystal Mackay, MA’05

When clinicians are focusing on lifestyle changes for the management and prevention of multiple chronic conditions, they will often ask patients about their alcohol consumption, smoking habits, exercise regime and diet. But what about the quality and duration of their sleep?

Researchers at Western University’s Schulich School of Medicine & Dentistry have shown that how well you sleep and for how long is linked to increased odds of living with multiple chronic conditions, and argue that promotion of good sleep habits should be given greater focus in clinical practice and public health.

The study, “Sleep behaviours and multimorbidity occurrence in middle-aged and older adults,” was recently published in the journal Sleep Medicine, and used data from more than 30,000 adults over the age of 45 who were part of the Canadian Longitudinal Study on Aging (CLSA).

“Sleep is still a neglected clinical and public health issue, and this study provides additional evidence of the potential role of sleep for the prevention and management of several chronic conditions,” said Dr. Saverio Stranges, Professor and Chair of the Department of Epidemiology and Biostatistics and principal investigator on the study.

The team looked specifically at the occurrence of multimorbidity, which is defined as having multiple chronic conditions (two or more) that have been diagnosed in a single individual. The conditions can include relatively common chronic disease such as diabetes and hypertension, to depression and cancer, among others.

The study found that there was a consistent relationship between the odds of multimorbidity and self-reported poor sleep quality and altered sleep duration, which includes both too much and too little sleep.

Specifically, male participants who were dissatisfied or very dissatisfied with their sleep had a 20 per cent increase in the odds of multimorbidity. And participants aged 65 to 74 years of age who self-reported dissatisfaction with their sleep quality had a 43 per cent increase in the odds of multimorbidity. 

When looking at sleep duration, while the study found a link between multimorbidity and getting too little sleep, the researchers actually found that too much sleep had a much stronger link.

Female participants who self-reported short sleep duration (less than 6 hours a night) had a 16 per cent increase in the odds of multimorbidity and those who self-reported long sleep duration (more than 8 hours a night) had a 44 per cent increase in the odds of multimorbidity. Male participants who self-reported long sleep duration had a 45 per cent increase in the odds of multimorbidity. 

Previous international research has shown an association between sleep and a range of chronic conditions, but this is the first Canadian study to look specifically at the relationship between sleep and multimorbidity among middle-aged and older adults.

“This study highlighted an important relationship between self-reported sleep patterns, both duration and satisfaction, and the odds of multimorbidity among older female and male adults in Canada,” said Kathryn Nicholson, PhD, Adjunct Assistant Professor at Schulich Medicine & Dentistry, who was the lead author on the study. “Although it is important to acknowledge that this relationship was cross-sectional and causation cannot be determined from this study, we were fortunate to utilize a comprehensive data source like the CLSA, which allowed us to examine both the self-reported patterns of sleep and the occurrence of multimorbidity.”

The authors point out in the paper that there is already established evidence showing that lack of sleep has negative effects on the cardio-metabolic, endocrine, immune and inflammatory systems, and that over the past several decades the population has been experiencing poorer quality of sleep.

“This is concerning because if poor quality of sleep can increase the risk of a range of chronic conditions, then we should be concerned about sleep hygiene and put that at the centre of our focus both as clinicians and as public health scientists,” said Stranges.

The researchers will be continuing their research by using the first set of follow-up data from the CLSA to begin to explore longitudinal patterns between multimorbidity and other health indicators.

“High-quality sleep can be very beneficial, but achieving this high-quality sleep can sometimes be a challenge.  We hope that this study will continue to emphasize the importance of focusing on sleep as a key health indicator and ideally, this assessment of sleep will include a focus on sleep quality and sleep duration and be a point of conversation during a clinical encounter for all patients living with multimorbidity,” said Nicholson.

Additional study authors are Rebecca Rodrigues, Kelly K. Anderson, PhD, and Piotr Wilk, PhD, from the Department of Epidemiology and Biostatistics, and Dr. Giuseppe Guaiana, from the Department of Psychiatry at the Schulich School of Medicine & Dentistry, Western University.