title: Religiosity/spirituality and mortality. A systematic quantitative review.
abstract: BACKGROUND
  The relationship between religiosity/spirituality and physical health has been the subject of growing interest in epidemiological research. We systematically reviewed prospective observational cohort studies of the association between this potentially protective psychological factor and mortality using meta-analytic methods.
  
  
  METHODS
  We searched general bibliographic databases: Medline, PsycINFO, Web of Science and PubMed (up to 20 March, 2008). Two reviewers independently extracted data on study characteristics, quality, and estimates of associations. Random effects meta-analyses, subgrouping, and sensitivity analysis were performed.
  
  
  RESULTS
  There were 69 studies (28 articles) and 22 studies (11 articles) investigating the association between religiosity/spirituality and mortality in initially healthy populations and diseased populations, respectively. The results of the meta-analyses showed that religiosity/spirituality was associated with reduced mortality in healthy population studies (combined hazard ratio = 0.82, 95% CI = 0.76-0.87, p <0.001), but not in diseased population studies (combined hazard ratio = 0.98, 95% CI = 0.94-1.01, p = 0.19). Notably, the protective effect of religiosity/spirituality in the initially healthy population studies was independent of behavioral factors (smoking, drinking, exercising, and socioeconomic status), negative affect, and social support. We divided studies according to the aspects of religiosity/spirituality measure examined, and found that organizational activity (e.g. church attendance) was associated with greater survival in healthy population studies. Multi-dimensional aspects were related to survival in both the healthy and diseased populations. Religiosity/spirituality was negatively associated with cardiovascular mortality in healthy population studies.
  
  
  CONCLUSIONS
  The current review suggests that religiosity/spirituality has a favorable effect on survival, although the presence of publication biases indicates that results should be interpreted with caution.
authors.affiliation: Psychobiology Group, Department of Epidemiology and Public Health, University College London, London, UK. y.chida@ucl.ac.uk
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Chida
authors.forename: Andrew
authors.initials: A
authors.lastname: Steptoe
authors.forename: Lynda H
authors.initials: LH
authors.lastname: Powell
mesh_terms: D000223:Adaptation, Psychological; D006801:Humans; D019122:Meditation; D011603:Psychophysiology; D012067:Religion; D029181:Spirituality