The findings suggest insomnia could increase people’s risk of type 2 diabetes, and that lifestyle or pharmacological treatments that improve insomnia could help to prevent or treat the condition.
The study, led by the University of Bristol, supported by the universities of Manchester, Exeter, and Harvard, and funded by Diabetes UK, is published in Diabetes Care.
Insomnia, not getting enough sleep, and having a later bedtime, have been linked in previous studies to a greater risk of type 2 diabetes. In this study, the research team assessed whether these associations are explained by causal effects of sleep traits on blood sugar levels.
The researchers used a statistical technique called Mendelian Randomization to see how five sleep measures – insomnia, sleep duration, daytime sleepiness, napping and morning or evening preference (chronotype) – were related to average blood sugar levels assessed by a measure called HbA1c levels. Using Mendelian Randomization, which groups people according to a genetic code randomly assigned at birth, allowed the researchers to remove any bias from the results.
The study of over 336,999 adults living in the UK, showed that people who reported that they often had difficulty getting to sleep or staying asleep had higher blood sugar levels than people who said they never, rarely, or only sometimes had these difficulties. The research team found no clear evidence for an effect of other sleep traits on blood sugar levels.
The findings could improve researchers understanding of how sleep disturbance influences type 2 diabetes risk. The study also suggests that lifestyle and/or pharmacological interventions that improve insomnia might help to prevent or treat diabetes.
James Liu, Senior Research Associate in the Bristol Medical School (PHS) and MRC Integrative Epidemiology Unit (IEU) and corresponding author on the paper, said: “We estimated that an effective insomnia treatment could result in more glucose lowering than an equivalent intervention, which reduces body weight by 14kg in a person of average height.
Currently, there are some treatments for insomnia. For example, UK guidelines to doctors recommend cognitive behavioral therapy (CBT) for insomnia, and short-term treatment of sleeping tablets or treatment with a hormone called melatonin if CBT does not work.
Dr. Faye Riley is Research Communications Manager at Diabetes UK. She said: “We know from past research that there’s a link between sleep and a person’s risk of type 2 diabetes, but it hasn’t been clear which comes first, bad sleep or higher blood sugars, or if other factors are at play.
“This new study, funded by Diabetes UK, gives us important insights into the direction of the relationship between sleep and type 2 diabetes, suggesting that insufficient sleep can cause higher blood sugars levels and could play a direct role in the development of type 2 diabetes. Knowing this could open up new approaches to help prevent or manage the condition.
“However, it’s important to remember that type 2 diabetes is a complex condition, with multiple risk factors. Eating a healthy balanced diet, being active, along with getting enough sleep, are all essential components of good health for everyone – including those at risk of, or living with, type 2 diabetes.”
Future studies to assess the impact of these insomnia treatments on glucose levels in people with and without diabetes could establish potential new treatments for the prevention and treatment of diabetes.
Increases in life expectancy have slowed or even ceased in the United States, the United Kingdom and comparable countries (Murphy, Xu, Kochanek, & Arias, 2017; Office for National Statistics, 2018). In the majority of countries, people have a high risk of premature mortality due to non-communicable diseases (NCDs), including diabetes, compared with other conditions (NCD Countdown 2030 Collaborators, 2018).
The mortality rates due to these NCDs are expected to increase by approximately 54% between 2016 and 2040, and deaths due specifically to type 2 diabetes are estimated to more than double worldwide (Foreman, Marquez, & Dolgert, 2018). Indeed, diabetes increases the risk of all-cause and cardiovascular mortality (Haffner, Lehto, Ronnemaa, Pyorala, & Laakso, 1998).
An international group led by the United Nations set a goal of reducing the rates of premature mortality due to NCD by one third by the year 2030, but only 16% of countries are on target for men and 19% of countries are on target for women (NCD Countdown 2030 Collaborators, 2018).
Given that NCDs are the leading causes of death and the rates of premature mortality rates are not declining as targeted, it is important to gain a greater understanding of the underlying causes of NCD-associated mortality. Here, we have used data from the UK Biobank to examine the effect of sleep disturbances and their interactions with diabetes, a major NCD, on morbidity and mortality.
Diabetes and early mortality have both been associated with inadequate sleep, including insufficient duration or poor quality of sleep (e.g., Akerstedt et al., 2017; Anothaisintawee, Reutrakul, Van Cauter, & Thakkinstian, 2016; Heslop, Smith, Metcalfe, Macleod, & Hart, 2002; Hublin, Partinen, Koskenvuo, & Kaprio, 2007; Kripke, Langer, Elliott, Klauber, & Rex, 2011; Tamakoshi & Ohno, 2004).
A number of studies have examined sleep disturbances or insomnia complaints in relation to mortality risk, and some observed significantly increased risk of mortality associated with these sleep-related complaints (Li et al., 2014; Sivertsen et al., 2014); however, others did not (Althuis, Fredman, Langenberg, & Magaziner, 1998; Kripke, Garfinkel, Wingard, Klauber, & Marler, 2002; Lovato & Lack, 2019; Rockwood, Davis, Merry, Macknight, & Mcdowell, 2001).
This discrepancy could be due to differences in the demographics of the sample, as ages and proportions of men and women varied among studies, as did sociodemographic and cultural factors. People with diabetes generally have poorer sleep quality (Trento et al., 2008) and poorer sleep quality has been associated with worse glycaemic control (Knutson, Ryden, Mander, & Van Cauter, 2006; Knutson, Van Cauter, Zee, Liu, & Lauderdale, 2011). Whether the combination of diabetes and frequent sleep disturbances affects mortality risk has not been previously reported.
The aims of the analyses presented here were to determine whether sleep disturbances were associated with increased risk of all-cause and cardiovascular disease (CVD) mortality in a large study of adults in the UK and to determine whether having both frequent sleep disturbances and diabetes was more strongly associated with mortality than either condition on its own. We hypothesized that frequent sleep disturbances would be associated with increased mortality risk, particularly in those with diabetes.
reference link : https://onlinelibrary.wiley.com/doi/10.1111/jsr.13392
More information: Junxi Liu et al, Assessing the Causal Role of Sleep Traits on Glycated Hemoglobin: A Mendelian Randomization Study, Diabetes Care (2022). DOI: 10.2337/dc21-0089