Re: Association between psychological distress and mortality: individual participant pooled analysis of 10 prospective cohort studies
“The best bridge between despair and hope is a good night's sleep” [E. Joseph Cossman]
We read with interest the article by Dr Russ and colleagues (1), showing a dose-response relationship between ‘psychological distress’ (measured with the GHQ-12) and mortality. The authors should be commended for their rigorous analysis, including appropriate modelling of relevant covariates. Consistent with campaigns to improve lifestyle and well-being factors, like diet and physical activity, we would also agree that increased recognition and appropriate management of sub-clinical psychological distress be considered.
We’re left wondering, however, what role insomnia and sleep disturbance may play in contributing to some of the observed relationships. We know, for example, that primary insomnia (poor sleep in the absence of co-morbid mental or physical illness) is associated with sub-clinical levels of psychological distress, in addition to general daytime and quality of life impairment (2,3). Longitudinally, insomnia is an independent risk factor for the future development of major depression (4) and anxiety disorder (5). Indeed, insomnia has been linked, in a number of studies, with both suicidal ideation and suicide death (see 6).
There are also strong relationships between insomnia and physical ill-health. At a cross-sectional level, insomnia is a risk factor for hypertension (7) and type II diabetes (8). Relatively recent data also suggest that insomnia with objective short sleep duration is a risk factor for early mortality, after controlling for several relevant covariates (9; see, also, 10). Finally, insomnia, in the absence of co-morbidity, has been associated with attenuated heart-rate (11) and blood pressure ‘dipping’ (12), from wake-to-sleep, as well elevated secretion of inflammatory markers (13) and increased activity of the HPA axis (14). Clearly, sleep timing, quality and duration are essential for optimal health and well-being (15).
Similar to Russ et al., we encourage greater investigation of the mechanisms linking psychological distress to adverse health outcomes and mortality, and would suggest focussed attention be placed on sleep as a potential contributing, yet modifiable (16) factor.
(1). Russ TC, Stamatakis E, Hamer M, et al. Association between psychological distress and mortality: individual participant pooled analysis of 10 prospective cohort studies. BMJ 2012; 345: e4933.
(2). Buysse DJ, Thompson W, Scott J, et al. Daytime symptoms of primary insomnia: A prospective analysis using ecological momentary assessment. Sleep Med 2007; 8: 198-208.
(3). Kyle SD, Morgan K, Espie CA. Insomnia and health-related quality of life. Sleep Med Rev 2010; 14: 69-82.
(4). Baglioni C, Battagliese G, Feige B, et al. Insomnia as a predictor of depression: A meta-analytic evaluation of longitudinal epidemiological studies. J Affect Disord 2011; 135: 10-19.
(5). Neckelmann D, Mykletun A, Dahl AA. Chronic insomnia as a risk factor for developing anxiety and depression. Sleep 2007; 30: 873-80.
(6). McCall WV, Blocker JN, D’Agostino R, et al. Insomnia severity is an indicator of suicidal ideation during a depression clinical trial. Sleep Med 2010; 11: 822-827.
(7). Vgontzas AN, Liao D, Bixler EO, et al. Insomnia with objective short sleep duration is associated with a high risk for hypertension. SLEEP 2009; 32: 491-497.
(8). Vgontzas AN, Liao D, Pejovic S, et al. Insomnia with objective short sleep duration is associated with type 2 diabetes: a population-based study. Diabetes Care 2009; 32: 980-5.
(9). Vgontzas AN, Liao D, Pejovic S, et al. Insomnia with Short Sleep Duration and Mortality: The Penn State Cohort. SLEEP 2010; 33: 1159-1164.
(10). Dew MA, Hoch CC, Buysse DJ, et al. Healthy older adults sleep predicts all-cause mortality at 4 to 19 years of follow-up. Psychosom Med 2003; 65: 63-73.
(11). Spiegelhalder K, Fuchs L, Ladwig J, et al. Heart rate and heart rate variability in primary insomnia. J Sleep Res 2011; 20: 137-145.
(12). Lanfranchi PA, Pennestri MH, Fradette L, et al. Nighttime blood pressure in normotensive subjects with chronic insomnia: implications for cardiovascular risk. SLEEP 2009; 32: 760-766.
(13). Burgos I, Richter L, Klein T, et al. Increased nocturnal interleukin-6 excretion in patients with primary insomnia: A pilot study. Brain Behav Immun 2006; 20: 246-253.
(14). Vgontzas AN, Bixler EO, Lin HM, et al. Chronic insomnia is associated with nyctohemeral activation of the hypothalamic–pituitary–adrenal axis: clinical implications. J Clin Endocrinol Metab 2001; 86: 3787–94.
(15). Luyster FS, Strollo PJ, Zee P, et al. Sleep: A health imperative. SLEEP 2012; 35: 727-734.
(16). Riemann, D, Perlis ML. The treatments of chronic insomnia: A review of benzodiazepine receptor agonists and psychological and behavioral therapies. Sleep Medicine Reviews 2009; 13: 205-214.
Competing interests: Prof. Espie is Clinical and Scientific Director of Sleepio Limited (an organization dedicated to helping people sleep better through raising awareness, research, and dissemination of behavioral advice) but has not received any income from the company.