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• Does loneliness and social isolation really increase the risk of CHD and stroke? Pooled results based on quality effect model
  Chang Xu
  Published on: 30 June 2016
• Loneliness and social isolation and increased risk of of coronary heart disease and stroke: clinical implications
  Redford B. Williams
  Published on: 10 June 2016

• Published on: 30 June 2016

  Does loneliness and social isolation really increase the risk of CHD and stroke? Pooled results based on quality effect model

  • Chang Xu, PhD candidate
  • Other Contributors:
    • Zhang Chao

  Dear editor,

  Loneliness and social isolation may lead to CHD and stroke? Valtorta et al. answered this question in a recent meta-analysis [1]. After pooling evidence based on 16 cohorts, they found that poor social relationships increase the risk of CHD and stroke. However, do things really like this? Maybe not. The problem is the random-effect (RE) model they used, which may lead to overconfident and biased re...

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  Dear editor,

  Loneliness and social isolation may lead to CHD and stroke? Valtorta et al. answered this question in a recent meta-analysis [1]. After pooling evidence based on 16 cohorts, they found that poor social relationships increase the risk of CHD and stroke. However, do things really like this? Maybe not. The problem is the random-effect (RE) model they used, which may lead to overconfident and biased results [2, 3]. Because under RE model, large studies were given more weight while the study quality was ignored [2]. Moreover, RE model is proved to link with underestimated coverage probability [3]. To solve these limitations, a widely accepted model called quality effect (QE), proposed by Doi et al. [4] has been gradually valued. In order to see if poor social relationships really increase the risk of CHD and stroke, we might re-pool the evidence by QE model [4]. We use the information of risk of bias summarized in Figure 2 and assume low risk of bias to be 2 score, high risk of bias 0 score, and unclear risk of bias 1 score to quantification estimator of quality. By doing so, the quality of each included study can be measured as total score (also known as Qi in QE model [4]). Under QE procedure, interestingly, loneliness and social isolation no longer lined with increased risk of CHD (RR=1.24; 95%CI: 0.97, 1.57) and stroke (RR=1.26; 95CI%: 0.95, 1.68). That is to say, when taking quality item into consideration, the pooled results no more statistical significance. Then, can we still claim poor social relationships increase the risk of CHD and stroke? Maybe we should treat the conclusion with caution.

  Conflicts: The authors declare no conflicts and interests. Reference 1. Valtorta NK, Kanaan M, Gilbody S, et al. Loneliness and social isolation as risk factors for coronary heart disease and stroke: systematic review and meta-analysis of longitudinal observational studies. Heart 2016; 102(13):1009-16.

  2. DerSimonian R, Laird N. Meta-analysis in clinical trials. Controlled Clinical Trials. 1986; 7:177-188.

  3. Brockwell SE, Gordon IR. A comparison of statistical methods for meta-analysis. Stat Med. 2001; 20(6): 825-840.

  4. Doi SA, Barendregt JJ, Khan S, et al. Advances in the meta- analysis of heterogeneous clinical trials II: The quality effects model. Contemp Clin Trials. 2015; 45(Pt A): 123-129.

  Conflict of Interest:

  None declared

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  Conflict of Interest:
  None declared.

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• Published on: 10 June 2016

  Loneliness and social isolation and increased risk of of coronary heart disease and stroke: clinical implications

  • Redford B. Williams, Professor

  The recent meta-analysis published in Heart by Valtorta et al. (1) showed that loneliness and social isolation are associated with increased coronary heart disease and stroke incidence in 16 large longitudinal studies conducted in high income countries. This finding is not surprising given the extensive literature documenting such harmful consequences of social isolation, including a study my research group published i...

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  The recent meta-analysis published in Heart by Valtorta et al. (1) showed that loneliness and social isolation are associated with increased coronary heart disease and stroke incidence in 16 large longitudinal studies conducted in high income countries. This finding is not surprising given the extensive literature documenting such harmful consequences of social isolation, including a study my research group published in 1992 (2) showing in a large sample of CHD patients that those who were not married and did not have a confident -- and hence likely to be lonely and socially isolated -- had a 5-year mortality (50%) that was nearly three times larger than that observed (18%) in patients with a spouse and/or partner.

  The most important implication of this finding is that interventions that reduce loneliness and social isolation have the potential to prevent disease development and improve prognosis once disease is present. There is encouraging preliminary evidence that such interventions have been developed and shown to reduce social isolation in CHD patients and other groups and improve prognosis in CHD patients. Bishop et al. (3) showed in a randomized controlled trial of Singaporean male coronary artery bypass graft surgery patients that psychosocial skills training delivered in small groups produced a significant increase in satisfaction with social support and satisfaction with life, as well as decreases in depression, anger and blood pressure at rest and in response to anger recall stress. Chun et al. (4) showed in a controlled clinical trial of Chinese medical students that this same psychosocial skills training produced a significant increase in social support as well as improvements in other psychosocial risk factors. Direct support for the clinical efficacy of such training delivered in small groups comes from two randomized controlled trials in Sweden (5, 6) showing that similar interventions produced significant reductions in mortality and recurrent cardiovascular events in CHD patients.

  The evidence from the Valtorta et al. study combines with the encouraging evidence that psychosocial skills training has been shown to reduce loneliness and social isolation in both CHD and healthy groups and improve prognosis in CHD patients to make a strong case that it is now appropriate to undertake large simple trials of such interventions in CHD patient groups. If such trials document that such training produces reduced morbidity and mortality, it would then be appropriate to undertake primary prevention trials in healthy groups.

  1. Valtorta NK, Kanaan M, Gilbody S, et al. Loneliness and social isolation as risk factors for coronary heart disease and stroke: systematic review and meta-analysis of longitudinal observational studies. Heart Published Online First 2016 (heartjnl-2015-308970).

  2. Williams, R.B., Barefoot, J.C., Califf, R.M., Haney, T.L., Saunders, W.B., Pryor, D.B., Hlatky, M.A., Siegler, I.C., Mark, D.B. Prognostic importance of social and economic resources among medically treated patients with angiographically documented coronary artery disease. JAMA. 1992;267:520-4.

  3. Bishop GD, Kaur D, Tan VLM, et al. Effects of a psychosocial skills training workshop on psychophysiological and psychosocial risk in patients undergoing coronary artery bypass grafting. Am Heart J 2005;150:602-609.

  4. Chun, L, Chu F, Wang H, Wang XP. Efficacy of Williams LifeSkills training for improving psychological health: a pilot comparison study of Chinese medical students. Asia Pac Psychiatry. 2014;6:161-9.

  5. Gulliksson M, Burell G, Vessby B, Lundin L, Toss H, Sverdsudd K. Randomized controlled trial of cognitive behavioral therapy vs standard treatment to prevent recurrent cardiovascular events in patients with coronary heart disease: Secondary Prevention in Uppsala Primary Health Care project (SUPRIM). Arch Intern Med. 2011;171:134-40.

  6. Orth-Gomer K, Schneiderman N, Wang HX, Walldin C, Blom M, Jernberg T. Stress reduction prolongs life in women with coronary disease: the Stockholm Women's Intervention Trial for Coronary Heart Disease (SWITCHD). Circ Cardiovasc Qual Outcomes. 2009;2:25-32.

  Sincerely,

  Redford B. Williams, M.D. Professor of Psychiatry and Behavioral Sciences, Professor of Medicine, Professor of Psychology and Neuroscience, Director, Behavioral Medicine Research Center

  Conflict of Interest:

  I am a founder and major stockholder in Williams LifeSkills,Inc., the company that developed the psychosocial skills training program used in the Bishop et al. (3) and Chun et al. (4) papers cited in my letter.

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  Conflict of Interest:
  None declared.

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