Cardiovascular Journal of Africa: Vol 32 No 4 (JULY/AUGUST 2021)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 4, July/August 2021 AFRICA 215
Dietary intakes of green leafy vegetables and incidence
of cardiovascular diseases
Akin Ojagbemi, Akinkunmi Paul Okekunle, Paul Olowoyo, Onoja Matthew Akpa, Rufus Akinyemi,
Bruce Ovbiagele, Mayowa Owolabi
Abstract
Aim: Low- and middle-income countries (LMICs) are current-
ly experiencing increasing cardiovascular disease (CVD) rates.
Green leafy vegetables (GLV), which are abundant in these
countries, are known to be particularly rich in cardioprotec-
tive nutrients. This study sought to determine the specific
effect of GLV intake on the incidence of CVD.
Methods: Previously published cohort studies on GLV intake
and incidence of CVD were retrieved through a systematic
search of Google Scholar, EMBASE, MEDLINE, HINARI
and Cochrane Library. A methodological evaluation of stud-
ies was carried out using the network of Ottawa scale, and a
fixed-effect meta-analysis was applied to estimate pooled rela-
tive risk (RR) and 95% confidence interval (CI). Heterogeneity
was determined using the I2 statistic. Sensitivity analysis was
done using the leave-one-study-out technique. All statistical
analysis was carried out at p < 0.05 using RevMan 5.4.
Results: The pooled RR (95% CI) of incident CVD events
from 17 studies was 0.93 (0.92–0.95). Specifically, GLV
intake was inversely related with incident cerebral infarction
(RR: 0.92; 95% CI: 0.88–0.96), heart disease (RR: 0.93; 95%
CI: 0.87–0.99) and other CVD events (RR: 0.95; 95% CI:
0.93–0.98).
Conclusion: GLV intake was associated with a lower incidence
of CVD, and may be a promising primary-prevention strategy
against CVD events. The findings are especially important in
LMICs where the burden of CVD remains high.
Keywords: green leafy vegetables, cardiovascular diseases, cere-
bral infarction, coronary heart disease, heart disease, meta-
analysis
Submitted 14/10/20, accepted 14/4/21
Published online 10/6/21
Cardiovasc J Afr 2021; 32: 215–223
DOI: 10.5830/CVJA-2021-017
Cardiovascular diseases (CVD) account for about 17.9 million
deaths annually1 and a huge burden of health expenditure
worldwide.2,3 Although CVD rates appear to be declining
globally,1,2,4-6 populations in low- and middle-income countries
(LMIC)6,7 continue to experience increasing CVD rates. CVD are
preventable and efforts are currently being mobilised to achieve
a 25% reduction in mortality rate attributable to CVD by 2025.8,9
Review Article
Department of Psychiatry, College of Medicine, University of
Ibadan, Ibadan, Nigeria
Akin Ojagbemi, MB BS, MSc, PhD
Department of Medicine, College of Medicine, University of
Ibadan; University College Hospital, Ibadan, Nigeria
Akinkunmi Paul Okekunle, PhD,
Mayowa Owolabi, MB BS, MSc, DrM, FAAN, FANA, FRCP,
FAcadMedS, FAS,
Department of Epidemiology and Medical Statistics, College
of Medicine, University of Ibadan, Ibadan, Nigeria
Akinkunmi Paul Okekunle, PhD
Onoja Matthew Akpa, BSc, MSc, PhD
Epidemiology Laboratory, Department of Food and Nutrition,
College of Human Ecology, Seoul National University, Seoul,
Korea
Akinkunmi Paul Okekunle, PhD
College of Medicine and Health Sciences, Afe Babalola
University; Department of Medicine, Federal Teaching
Hospital, Ado-Ekiti, Nigeria
Paul Olowoyo, MB BS, FWACP
Centre for Genomic and Precision Medicine, College of
Medicine, University of Ibadan, Ibadan, Nigeria
Onoja Matthew Akpa, BSc, MSc, PhD
Rufus Akinyemi, MB BS, MSc, PhD, MWACP, FMCP
Mayowa Owolabi, MB BS, MSc, DrM, FAAN, FANA, FRCP,
FAcadMedS, FAS,
Institute of Advanced Medical Research and Training,
College of Medicine, University of Ibadan, Ibadan, Nigeria
Rufus Akinyemi, MB BS, MSc, PhD, MWACP, FMCP
Weill Institute for Neurosciences; School of Medicine,
University of California, San Francisco, California, USA
Bruce Ovbiagele, MB BS, MSc, MAS, MBA, FAAN
Department of Medicine, College of Medicine, University
of Ibadan; University College Hospital; Blossom Specialist
Medical Centre, Ibadan, Nigeria
Mayowa Owolabi, MB BS, MSc, DrM, FAAN, FANA, FRCP,
FAcadMedS, FAS,