Our meta-analysis demonstrated that insomnia symptoms of difficulty initiating sleep, difficulty maintaining sleep and non-restorative sleep were associated with an increased risk of future cardio-cerebral vascular events.

Fifteen studies (23 cohorts) were included. Positive associations were observed between difficulty initiating sleep, difficulty maintaining sleep and non-restorative sleep with risk of cardio-cerebral vascular events. The pooled relative risks and 95% confidence intervals were 1.27 (1.15–1.40), 1.11 (1.04–1.19) and 1.18 (1.05–1.33), respectively. However, less evidence existed to support the conclusions about the association between early-morning awakening and cardio-cerebral vascular events.

PubMed, Web of science and the Cochrane Library were searched without language restriction. Prospective cohort studies of adults with at least a 2-year follow-up duration were included. Random effect models were used in order to pool the results for each insomnia symptom. Subgroup and sensitivity analyses were conducted in order to assess potential heterogeneity, and funnel plots and Egger’s tests were used in order to assess publication bias.

Insomnia symptoms have been suggested to be associated with the risk of cardio-cerebral events. However, the results of previous studies have been inconsistent. Therefore, we conducted a meta-analysis to examine whether there were associations between cardio-cerebral vascular events and insomnia symptoms, including difficulty initiating sleep, difficulty maintaining sleep, early-morning awakening or non-restorative sleep.

References

1. Ge, B, Guo, X. Short and long sleep durations are both associated with increased risk of stroke: A meta-analysis of observational studies . Int J Stroke 2015 ; 10: 177 – 184 .

Google Scholar SAGE Journals | ISI

2. Edinger, JD, Bonnet, MH, Bootzin, RR. Derivation of research diagnostic criteria for insomnia: Report of an American Academy of Sleep Medicine work group . Sleep 2004 ; 27: 1567 – 1596 .

Google Scholar Crossref | Medline | ISI

3. National Institution of Health, What Are the Signs and Symptoms of Insomnia? https://www.nhlbi.nih.gov/health/health-topics/topics/inso/signs (2011, accessed 14 December 2016).

Google Scholar

4. Schlack, R, Hapke, U, Maske, U. [Frequency and distribution of sleep problems and insomnia in the adult population in Germany: Results of the German Health Interview and Examination Survey for Adults (DEGS1)] . Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2013 ; 56: 740 – 748 .

Google Scholar Crossref | Medline | ISI

5. Troxel, WM, Buysse, DJ, Matthews, KA. Sleep symptoms predict the development of the metabolic syndrome . Sleep 2010 ; 33: 1633 – 1640 .

Google Scholar Crossref | Medline | ISI

6. Irwin, MR, Olmstead, R, Carroll, JE. Sleep disturbance, sleep duration, and inflammation: A systematic review and meta-analysis of cohort studies and experimental sleep deprivation . Biol Psychiatry 2016 ; 80: 40 – 52 .

Google Scholar Crossref | Medline | ISI

7. Baglioni, C, Battagliese, G, Feige, B. Insomnia as a predictor of depression: A meta-analytic evaluation of longitudinal epidemiological studies . J Affect Disord 2011 ; 135: 10 – 19 .

Google Scholar Crossref | Medline | ISI

8. Meng, L, Zheng, Y, Hui, R. The relationship of sleep duration and insomnia to risk of hypertension incidence: A meta-analysis of prospective cohort studies . Hypertens Res 2013 ; 36: 985 – 995 .

Google Scholar Crossref | Medline | ISI

9. Canivet, C, Nilsson, PM, Lindeberg, SI. Insomnia increases risk for cardiovascular events in women and in men with low socioeconomic status: A longitudinal, register-based study . J Psychosom Res 2014 ; 76: 292 – 299 .

Google Scholar Crossref | Medline | ISI

10. Laugsand, LE, Strand, LB, Platou, C. Insomnia and the risk of incident heart failure: A population study . Eur Heart J 2014 ; 35: 1382 – 1393 .

Google Scholar Crossref | Medline | ISI

11. Laugsand, LE, Vatten, LJ, Platou, C. Insomnia and the risk of acute myocardial infarction: A population study . Circulation 2011 ; 124: 2073 – 2081 .

Google Scholar Crossref | Medline | ISI

12. Hsu, CY, Chen, YT, Chen, MH. The association between insomnia and increased future cardiovascular events: A nationwide population-based study . Psychosom Med 2015 ; 77: 743 – 751 .

Google Scholar Crossref | Medline | ISI

13. Rod, NH, Vahtera, J, Westerlund, H. Sleep disturbances and cause-specific mortality: Results from the GAZEL Cohort Study . Am J Epidemiol 2011 ; 173: 300 – 309 .

Google Scholar Crossref | Medline | ISI

14. Helbig, AK, Stockl, D, Heier, M. Symptoms of insomnia and sleep duration and their association with incident strokes: Findings from the population-based MONICA/KORA Augsburg Cohort Study . PLoS One 2015 ; 10: e0134480 – e0134480 .

Google Scholar Crossref | ISI

15. Westerlund, A, Bellocco, R, Sundstrom, J. Sleep characteristics and cardiovascular events in a large Swedish cohort . Eur J Epidemiol 2013 ; 28: 463 – 473 .

Google Scholar Crossref | Medline | ISI

16. Li, Y, Zhang, X, Winkelman, JW. Association between insomnia symptoms and mortality: A prospective study of U.S. men . Circulation 2014 ; 129: 737 – 746 .

Google Scholar Crossref | Medline | ISI

17. Rod, NH, Kumari, M, Lange, T. The joint effect of sleep duration and disturbed sleep on cause-specific mortality: Results from the Whitehall II Cohort Study . PLoS One 2014 ; 9: e91965 – e91965 .

Google Scholar Crossref | Medline | ISI

18. Li, M, Zhang, XW, Hou, WS. Insomnia and risk of cardiovascular disease: A meta-analysis of cohort studies . Int J Cardiol 2014 ; 176: 1044 – 1047 .

Google Scholar Crossref | Medline | ISI

19. Sofi, F, Cesari, F, Casini, A. Insomnia and risk of cardiovascular disease: A meta-analysis . Eur J Prev Cardiol 2014 ; 21: 57 – 64 .

Google Scholar SAGE Journals | ISI

20. Stroup, DF, Berlin, JA, Morton, SC. Meta-analysis of observational studies in epidemiology – A proposal for reporting . JAMA 2000 ; 283: 2008 – 2012 .

Google Scholar Crossref | Medline | ISI

21. Wells GA, Shea B, O’Connell D, et al. The Newcastle–Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses, http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp (2011, accessed 14 December 2014).

Google Scholar

22. Suzuki, E, Yorifuji, T, Ueshima, K. Sleep duration, sleep quality and cardiovascular disease mortality among the elderly: A population-based cohort study . Prev Med 2009 ; 49: 135 – 141 .

Google Scholar Crossref | Medline | ISI

23. Ingelsson, E, Lind, L, Arnlov, J. Sleep disturbances independently predict heart failure in overweight middle-aged men . Eur J Heart Fail 2007 ; 9: 184 – 190 .

Google Scholar Crossref | Medline | ISI

24. Nilsson, PM, Nilsson, JA, Hedblad, B. Sleep disturbance in association with elevated pulse rate for prediction of mortality – Consequences of mental strain? J Intern Med 2001 ; 250: 521 – 529 .

Google Scholar Crossref | Medline | ISI

25. Meisinger, C, Heier, M, Lowel, H. Sleep duration and sleep complaints and risk of myocardial infarction in middle-aged men and women from the general population: The MONICA/KORA Augsburg Cohort Study . Sleep 2007 ; 30: 1121 – 1127 .

Google Scholar Crossref | Medline | ISI

26. Mallon, L, Broman, JE, Hetta, J. Sleep complaints predict coronary artery disease mortality in males: A 12-year follow-up study of a middle-aged Swedish population . J Intern Med 2002 ; 251: 207 – 216 .

Google Scholar Crossref | Medline | ISI

27. Jaussent, I, Empana, JP, Ancelin, ML. Insomnia, daytime sleepiness and cardio-cerebrovascular diseases in the elderly: A 6-year prospective study . PLoS One 2013 ; 8: e56048 – e56048 .

Google Scholar Crossref | Medline | ISI

28. Schwartz, SW, Cornoni-Huntley, J, Cole, SR. Are sleep complaints an independent risk factor for myocardial infarction? Ann Epidemiol 1998 ; 8: 384 – 392 .

Google Scholar Crossref | Medline | ISI

29. Eaker, ED, Pinsky, J, Castelli, WP. Myocardial infarction and coronary death among women: Psychosocial predictors from a 20-year follow-up of women in the Framingham Study . Am J Epidemiol 1992 ; 135: 854 – 864 .

Google Scholar Crossref | Medline | ISI

30. Higgins, JP, Thompson, SG, Deeks, JJ. Measuring inconsistency in meta-analyses . BMJ (Clin Res Ed) 2003 ; 327: 557 – 560 .

Google Scholar Crossref | Medline

31. Begg, CB, Mazumdar, M. Operating characteristics of a rank correlation test for publication bias . Biometrics 1994 ; 50: 1088 – 1101 .

Google Scholar Crossref | Medline | ISI

32. Egger, M, Davey Smith, G, Schneider, M. Bias in meta-analysis detected by a simple, graphical test . BMJ (Clin Res Ed) 1997 ; 315: 629 – 634 .

Google Scholar Crossref | Medline

33. Spiegel, K, Leproult, R, Van Cauter, E. Impact of sleep debt on metabolic and endocrine function . Lancet 1999 ; 354: 1435 – 1439 .

Google Scholar Crossref | Medline | ISI

34. Zhang, J, Ma, RC, Kong, AP. Relationship of sleep quantity and quality with 24-hour urinary catecholamines and salivary awakening cortisol in healthy middle-aged adults . Sleep 2011 ; 34: 225 – 233 .

Google Scholar Crossref | Medline | ISI

35. Lanfranchi, PA, Pennestri, MH, Fradette, L. Nighttime blood pressure in normotensive subjects with chronic insomnia: Implications for cardiovascular risk . Sleep 2009 ; 32: 760 – 766 .

Google Scholar Crossref | Medline | ISI

36. Nakazaki, C, Noda, A, Koike, Y. Association of insomnia and short sleep duration with atherosclerosis risk in the elderly . Am J Hypertens 2012 ; 25: 1149 – 1155 .

Google Scholar Crossref | Medline | ISI

37. Strand, LB, Laugsand, LE, Wisloff, U. Insomnia symptoms and cardiorespiratory fitness in healthy individuals: The Nord-Trondelag Health Study (HUNT) . Sleep 2013 ; 36: 99 – 108 .

Google Scholar Crossref | Medline | ISI

38. Cintra, F, Bittencourt, LR, Santos-Silva, R. The association between the Framingham Risk Score and sleep: A Sao Paulo epidemiological sleep study . Sleep Med 2012 ; 13: 577 – 582 .

Google Scholar Crossref | Medline | ISI