TABLE 1.
Included epidemiological studies examining the effect of a vegan diet on the risk of cardiovascular events1
| Reference | Country | Population | Follow-up | Diet assessment | Vegan diet | Duration of time as vegan before study start | Control diet definition | Outcome assessment | Outcomes (types) | Outcomes (n) | Main findings2 | Adjustment or matching |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Prospective cohort studies | ||||||||||||
| Orlich et al., 2013 (24) | USA | 40,907 participants from AHS-2 studyMean age (y): Vegan (n = 5,548): 57.9 ± 13.6Non-vegetarian (n = 35,359): 55.9 ± 13.1Women: 66% | 5.8 y | Self-administered quantitative FFQ | Definition: No eggs, dairy, fish, all other meats <1 a monthMean duration: 21 y | Mean: 21 years | Non-fish meats >1 ×/mo and all meats combined >1 ×/wk | Mortality records from USA National Death Index | CVD deathsCHD deaths | 987372 | HR, 0.91; 95% CI, 0.71–1.16HR, 0.90; 95% CI, 0.60–1.33 | Adjusted for age, sex, region, race, income, education, marital status, smoking, exercise, alcohol intake, sleep, menopausal status (females), HRT (if postmenopausal) |
| Tong et al., 2019 (23) | UK | 26,260 participants from the EPIC-Oxford studyVegan (n = 1832)Meat-eater (n = 24,428)Age range (y): 35–59Women: 75% | Max: 18.1 y | Self-administered quantitative FFQ | Definition: No meat, fish, dairy, eggs in 2010 and at baselineMean duration: not reported | NG | Meat, regardless of whether they consumed fish, dairy, eggs | Hospital records | Acute MICHDStrokeHaemorrhagic strokeIschemic stroke | 78828201072300519 | HR, 0.77; 95% CI, 0.46–1.27HR, 0.82; 95% CI, 0.64–1.05HR, 1.35; 95% CI, 0.95–1.92HR, 1.09; 95% CI, 0.53–2.26HR, 1.54; 95% CI, 0.95–2.48 | Adjusted for age, sex, region, recruitment method and year, education, Townsend deprivation index, smoking, alcohol intake, exercise, supplement use, HRT (females), oral contraceptive use |
| Key et al., 1999 (22) | USA, UK, Germany | 32,519 participants from AM, HFS, AH, Heidelberg and Oxford vegetarian studies | 11.7 y | Self-administered quantitative FFQ | Definition: No animal products | NG | Regular meat eaters consumed meat ≥1 ×/wk | Medical records linked to mortality records | CHD deaths | 1743 | HR, 0.74; 95% CI, 0.46–1.21 | Adjusted for age, sex, smoking, study |
| Vegan (n = 753)Meat-eater (n = 31,766)Age range (y): 16–89Women: not given | Mean duration: not reported | Cerebrovascular disease deaths (stroke) | 617 | HR. 0.70; 95% CI. 0.25–1.98 | ||||||||
| Esselstyn et al., 2014 (12) | USA | 198 self-selected patients counselled in plant-based nutrition at the CCP | 44.2 mo | Self-reported elimination of dairy, fish, meat and added oils | Definition: No dairy, fish, meat, added oils; avoided avocado, nuts, excess salt, caffeine, fructose | 0 days | Not reported | Self-report or next of kin | Improved angina, CAD progression, CVD deaths | 144, 15, 2 | 1 major cardiac event and 17 interventions occurred in the adherent participants (10%) and 13 (62%) in nonadherent participants | Unadjusted |
| Vegan (n = 177) | Mean duration: not reported | |||||||||||
| Non-vegan (n = 21) | ||||||||||||
| Mean age (y): 62.9 ± 10.0 | ||||||||||||
| Women: 88% | ||||||||||||
| Cross-sectional studies | ||||||||||||
| Fontana et al., 2007 (28) | USA | 3 groups of subjects3 (21 per group) recruited via the SLV society, RFOM, local advertising and endurance runners | N/A | 7-d food record | Definition: No meat, dairy, eggs, cooked and processed foods | Range: 2–10 years | Typical Western diets | Ultrasound with transducer | Carotid artery IMT (mm) | N/A | IMT: 0.6 ± 0.1 versus 0.7 ± 0.1 in the low-calorie, low-protein, vegan diet group versus Western diet group, respectively (P < 0.001) | Adjusted for age, gender, BMI (endurance runners), height (healthy, sedentary, nonobese group) |
| Vegan (n = 21) | Mean duration: 4.4 ± 2.8 y | |||||||||||
| Western diet (n = 42) | ||||||||||||
| Age range (y): 5–35 | ||||||||||||
| Women: 38% | ||||||||||||
| Randomized controlled trials | ||||||||||||
| Shah et al., 2018 (25) | USA | 100 (1:1) randomized participants from the EVADE CAD trial with a | 8 wk | 24-h dietary recall and 4-d food record | Definition: No meat, poultry, eggs, dairy, seafood Mean duration: 8 wk | 0 days | AHA-recommended diet group encouraged to consume ≤5 oz of animal protein/day, | Self-report | MI, repeat coronary revascularization, | 0 | No events | N/A |
| history of angiographically defined CAD | only low-fat/fat-free dairy if dairy was | |||||||||||
| Median age (y):Vegan (n = 50): 63.0 (57.0–68.0) | consumed, fish ≥2×/week | Determined by clinical neurologist consultant | Cerebrovascular disease | 2 | 0 versus 2 events | N/A | ||||||
| AHA diet (n = 50): 59.5 (53.0–67.0) Women: 15% | Measured using the EndoPat Device | Endothelial function | N/A | No significant change in endothelial function over time (vegans: baseline 1.96; 1.62, 2.70 at 8 weeks 1.88; 1.61, 2.61; P = 0.86; AHA diet: baseline 2.12; 1.85, 2.48 at 8 weeks 1.84; 1.68, 2.13; P = 0.12). No significant change in status of endothelial function (abnormal (<1.67) versus normal) was noted in 75% of vegan and 84% of AHA diet participants (P = 0.41); a change from normal to abnormal was found in 10% of vegan and 14% of AHA diet participants (P = 0.73) and a change from abnormal to normal in 15% of vegan and 3% of AHA diet participants (P = 0.11) | N/A | |||||||
| Wright et al., 2017 (26) | New Zealand | 65 participants of the randomized BROAD randomised control trial Vegan (n = 33) Regular diet (n = 32) Age range (y): 35–70 Women: 60% | 6–12 mo | 3-d food recall | Definition: Low-fat plant-based diet including whole grains, legumes, vegetables, fruits. Mean duration: 1 y | 0 days | Regular diet | Notification on transfer to higher cardiac-related care | CVD events | 0 | No cardiovascular events were recorded; the program led to significant improvements in CRP, BMI, cholesterol, and other risk factors | N/A |
1
AH study, Adventist Health study; AHS-2, Adventist Health 2 Study; AM study, Adventist Mortality study; CAD, coronary artery disease; CCP, Cleveland Clinic Program; CHD, coronary heart disease; CVD, cardiovascular disease; EPIC-Oxford, European Prospective Investigation into Cancer and Nutrition; EVADE CAD, Effects of a Vegan versus American Heart Association–Recommend Diet in Coronary Artery Disease; HFS study, Health Food Shoppers study; HRT, hormone replacement therapy; IMT, intima-media thickness; MI, myocardial infarction; N/A, not applicable; NG, not given; RFOM, Raw Food Online Magazine; SLV Society, St. Louis Vegetarian Society.
2
Outcome comparing the adherence to a vegan dietary pattern to a nonvegan dietary pattern. The least restrictive diet was chosen as a comparison group (e.g., omnivorous diet).
3
The 3 groups consisted of a low-calorie low-protein vegan diet group, an endurance runner group and a Western diet group.