Table 1.
PICOS | Inclusion Criteria | Exclusion Criteria |
---|---|---|
Population | Adults (>18 years old) | Children and adolescents (<18 years old) |
Intervention/ Exposure |
Plant-based diets (i.e., vegan/vegetarian diets) administered as an intervention, or plant-based dietary scores measured by food frequency questionnaire | Non-plant-based dietary patterns; unclear definitions or measurement of dietary exposures. |
Comparison | For RCTs: control groups consisting of usual diet or another dietary pattern. For cohort studies: plant-based diet groups compared to non-vegetarian diet groups. For diet scores/indices, comparisons between quintiles or continuous measures (e.g., per 10-unit increment) were included | Comparisons where other exposures are included with diet vs. comparator, e.g., exercise, fasting, etc.; multifactorial interventions. |
Outcomes | Lipid biomarkers: TC, LDL-C (directly measured LDL-C was included over calculated LDL-C where both were reported); HDL-C; Non-HDL-C; VLDL-C; TGs Lipoprotein biomarkers: VLDL-P concentrations; IDL-P concentrations; LDL-P concentrations; HDL-P concentrations; Non-HDL-P concentrations; apoB; Small, medium, large VLDL-P, LDL-P, HDL-P concentrations; Mean VLDL-P size; Mean LDL-P size; Mean HDL-P size Inflammatory biomarkers: C3; hsCRP/CRP; IL-6; TNF-α; Adiponectin; Leptin; LAR; Resistin; PAI-1; WBCs; Neutrophils; Lymphocytes; NLR; Monocytes; Basophils; Eosinophils; GlycA |
All other outcomes Postprandial lipid outcomes Self-reported outcomes without objective measurements |
Study type | RCTs (parallel, crossover, metabolic ward), prospective cohort studies, cross-sectional studies (only for studies using dietary scores/indices), systematic reviews and meta-analyses (of randomised controlled trials and/or prospective cohort studies) | Non-randomised trials, intervention trials without a control/comparator, reviews, case reports/series, editorials, commentaries, meeting abstracts, studies with legitimate expressions of concern |
Abbreviations: apoB: apolipoprotein B; C3: complement component 3; CRP: C-reactive protein; GlycA: glycoprotein A; HDL-C: high-density lipoprotein cholesterol; HDL-P: high-density lipoprotein particle; hsCRP: high-sensitivity C reactive protein; IDL-P: intermediate-density lipoprotein particle; IL-6: interleukin 6; LAR: leptin-to-adiponectin ratio; LDL-C: low-density lipoprotein cholesterol; LDL-P: low-density-lipoprotein particle; NLR: neutrophil–lymphocyte ratio; PAI-1: plasminogen activator inhibitor 1; RCTs: randomised controlled trials; TC: total cholesterol; TGs: triglycerides; TNF-α: tumour necrosis factor alpha; VLDL-C: very-low-density lipoprotein cholesterol; VLDL-P: very-low-density lipoprotein particle; WBCs: white blood cells.