Hello,
I just listened to the sleep podcast and it was very interesting and eye-opening. Thank you Austin, Jordan, and Nate for taking the time to put that together.
I started doing more research into sleep, specifically insomnia, and its health risks and relation to mortality after listening to the podcast and reading the “Where should my priorities be to improve my health?” article, specifically the section on sleep. In my research, I came across some conflicting information regarding the consequences and health risks of insomnia, and I’m curious to hear what you guys think.
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In a 2005 consensus statement on insomnia released by the NIH, it was noted that insomnia frequently appears co-morbid with at least one disorder, and that insomnia may affect quality of life. It goes on to add that “the association of insomnia with premature death has not been studied”. The challenges of studying insomnia, the paper states, is “because most studies have been cross-sectional observations of affected persons rather than prospective studies of persons beginning prior to the onset of insomnia, decisions cannot be made as to which of its correlates are actually causal.”
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American Academy of Sleep Medicine’s Clinical Guidelines for the Evaluation and Management of Chronic Insomnia in Adults also notes that insomnia appears co-morbid with other conditions. Additionally, it mentions how there appears to be a bidirectional risk relationship between insomnia and psychiatric disorders, which you guys mentioned in the podcast.
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A 2012 Review of Chronic Insomnia by the Lancet concluded the following: “Although insomnia has traditionally been conceptualized as a symptom of another disorder, longitudinal studies suggest that it can be a risk factor for new onset psychiatric disorders, most notably depression, anxiety, and substance misuse disorders.” Contrast the above research with the follow research that concludes that the association between insomnia and increased risk of mortality and other health problems, particularly CVD and other non-psychiatric health conditions, is strong:
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The 2019 VA/DoD chronic insomnia guidelines, which you guys discussed in the podcast, says that there are “mental and physical health risks of poor sleep (e.g., anxiety, depression, suicide, CVD)”. The paper does not cite a inline source for the previous statement with regards to what research they were looking at.
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With that said, the previous paper does mention the 2011 NIH’s Sleep Disorders Research Plan towards the beginning of the guidelines (though not in reference to the previously mentioned statement). The NIH’s 2011 Sleep Disorder Research Plan noted that “short and long sleep duration is associated with up to a 2 fold increased risk of obesity, diabetes, hypertension, incident cardiovascular disease, stroke, depression, substance abuse, and all-cause mortality in multiple studies.”
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The research this 2011 NIH paper cited to support this was the 2006 National Academies Extent and Health Consequences of Chronic Sleep Loss and Sleep Disorders. This review concluded, out of other things, that “sleep loss is associated with increased age-specific mortality”. The authors cited three large, population-based, prospective studies (Kripke et al., 2002; Tamakoshi et al., 2004; Patel et al., 2004). These studies all seem to conclude that the risk is a “U” shape, with sleeping less than or more than 6-7 hours a night associated with an increased risk of morality. One of the studies, the 2002 one by Kripke et al., concluded the following: “Patients can be reassured that short sleep and insomnia seem associated with little risk distinct from comorbidities. Slight risks associated with 8 or more hours of sleep and sleeping pill use need further study. Causality is unproven.”
- A 2015 New England Journal of Medicine review concluded that insomnia is an independent risk factor for depression, cardiovascular disease, and diabetes.
What are your guys thoughts on the difference between these two differing stances in research regarding the associations between insomnia and health risks (specifically non-psychiatric ones) and overall mortality? While all the research reviews I looked at seems to agree on insomnia being a comorbid factor for other diseases, and having some possible bidirectionality with psychiatric illnesses, the latter body of research I mentioned above extends it to physical illnesses and an association with an increase in overall morality risk.