Vegetarian diet, Seventh Day Adventists and risk of cardiovascular mortality: A systematic review and meta-analysis

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    1 This author takes responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.
    Chun Shing Kwok
    Correspondence
    Corresponding author at: Institute of Cardiovascular Sciences, University of Manchester, Manchester Royal Infirmary, Manchester M13 9WL, UK. Tel.: +44 161 276 8666; fax: +44 161 2767956.
    Footnotes
    1 This author takes responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.
    Affiliations
    Cardiovascular Institute, University of Manchester, Manchester, UK
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  • Author Footnotes
    1 This author takes responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.
    Saadia Umar
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    Central Manchester Foundation Trust, Manchester, UK
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    1 This author takes responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.
    Phyo K. Myint
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    School of Medicine & Dentistry, University of Aberdeen, Foresterhill, Aberdeen, UK
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    1 This author takes responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.
    Mamas A. Mamas
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    Cardiovascular Institute, University of Manchester, Manchester, UK
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    1 This author takes responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.
    Yoon K. Loke
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    Norwich Medical School, University of East Anglia, Norwich, UK
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  • Author Footnotes
    1 This author takes responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.

      Highlights

      • Vegetarian diet is potentially associated with reduced ischaemic heart disease.
      • The benefits of a vegetarian diet are most apparent among Seventh-Day Adventist.
      • Reductions in all-cause mortality were not replicated in the non-Adventist studies.
      • Evidence supporting a vegetarian diet is driven by Seventh-Day Adventists studies.
      • The effect of vegetarian diet in other non-Adventist cohorts remains unproven.

      Abstract

      Background

      Dietary interventions are an important component of cardiovascular risk factor management although their impact on cardiovascular risk and mortality remains uncertain. We have studied influence of a vegetarian diet on cardiovascular risk and mortality.

      Methods

      We searched MEDLINE and EMBASE for comparative studies that evaluated clinical outcomes associated with vegetarian diet as compared to non-vegetarian controls or the general population. Relevant studies were pooled using random effects meta-analysis for risk of death, ischaemic heart disease (IHD) and cerebrovascular disease. We conducted subgroup analysis according to specific type of cohort (e.g. Seventh Day Adventist [SDA]) and gender.

      Results

      Eight studies met the inclusion criteria with 183,321 participants (n = 183,321). There was significant heterogeneity in all the meta-analyses, particularly evident with the studies of SDA. In all instances, we found that SDA studies showed greater effect size as compared to non-SDA studies: death (RR 0.68 95% CI 0.45–1.02 vs RR 1.04 95% CI 0.98–1.10), ischaemic heart disease (IHD) (RR 0.60 95% CI 0.43–0.80 vs RR 0.84 95% CI 0.74–0.96) and cerebrovascular disease (RR 0.71 95% CI 0.41–1.20 vs RR 1.05 95% CI 0.89–1.24). Sex specific analyses showed that IHD was significantly reduced in both genders but risk of death and cerebrovascular disease was only significantly reduced in men.

      Conclusions

      Data from observational studies indicates that there is modest cardiovascular benefit, but no clear reduction in overall mortality associated with a vegetarian diet. This evidence of benefit is driven mainly by studies in SDA, whereas the effect of vegetarian diet in other cohorts remains unproven.

      Keywords

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