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 221
constituents of GLV are known to promote optimal health and
protect against several diseases.29,59 The fibre component of GLV
is also known for its cholesterol-lowering effects.60 Similarly, folic
acid (a constituent of GLV) intake is inversely associated with
homocysteinaemia,61,62 a known risk factor for atherosclerosis
and ischaemic stroke.63-65 Furthermore, micronutrients in GLV
may promote cardiovascular integrity, haemostasis (Vitamin K
content), neuronal transmission (calcium content), antioxidant
activity (vitamins C and E content)32,66 and vasodilatory effects
(nitrates content).67,68
There are existing gaps in the literature on the effect of GLV
on CVD outcomes not covered by the present systematic review
and meta-analysis. For example, the mode of preparation and
preservation of GLV on CVD outcomes remains unclear.
Similarly, the underlying molecular mechanisms mediating the
protective effect of GLV remains incomplete. These gaps in
our understanding of the relationship between GLV and CVD
could be the basis of future cohort studies and clinical trials.
Limitations, strengths and recommendations
GLV are not consumed singly in diets. Similarly, higher GLV
consumption in the presence of exposure to traditional risk
factors of CVD (such as smoking, alcohol intake, low physical
activity) does not imply less CVD risk. Our study considered
populations exposed to higher GLV intakes in their overall diet
only, independent of the magnitude of consumption of other
food items.
This systematic review and meta-analysis has other
limitations. First, this meta-analysis did not investigate the
relationship between GLV and CVD outcomes according to
ethnic background and country of study due to the limited
number of studies on the subject. Most studies were from the
United States. There were limited studies from populations of
African and Asian ancestry. This hindered us from performing
subgroup analyses by region and ethnicity as indicated in the
study protocol.
Second, there were methodological differences in the
estimation of GLV intake among studies included in this
systematic review and meta-analysis. However, these differences
are likely insignificant given the consistent direction and strength
of the relationship in our reported pooled-effect estimate after
stratifying the meta-analysis across several subgroups. However,
it is necessary to establish models that can uniformly quantitate
GLV consumption across different populations.
Third, our search for grey literature was limited to informal
requests for unpublished data and reports on the effect of GLV
on CVD from local specialists in human nutritional research.
This strategy did not result in the retrieval of additional
primary data suitable for our meta-analysis objectives.
A key strength of our study is that it may be the first to
summarise data on the association between GLV intake and
not only incident CVD events in general but also subtypes of
these outcomes.
Conclusion
Our meta-analysis demonstrated that a higher intake of
GLV was associated with a lower incidence of CVD events,
independent of subtypes of CVD manifestation. Promoting the
consumption of GLV may be useful for the management and
prevention of CVD. Also, dietary strategies that incorporate
GLV consumption may be encouraged and promoted. Further
studies are necessary to determine the underlying mechanism(s)
and the significance of duration of exposure on the magnitude
of the effect of GLV on CVD events. In particular, a future
multicentre cohort study with uniform quantification of GLV
consumption and duration between exposure and CVD events
would be desirable to confirm these findings.
The SIREN (U54HG007479) and SIBS genomics (R01NS107900) studies were
funded by the National Institutes of Health under the H3Africa initiative.
Investigators are further supported by NIH grant SIBS Gen Gen R01NS107900-
02S1; ARISES R01NS115944-01; H3Africa CVD Supplement 3U24HG009780-
03S5 and PINGS 2 R01HL152188. OMA and APO received partial funding from
the Postgraduate College, University of Ibadan, Nigeria. APO received support
from the Brain Pool Program through the National Research Foundation of
Korea, funded by the Ministry of Science & ICT (2020H103A104081265). The
funders had no role in study design, data collection, analysis, interpretation, deci-
sion to publish or preparation of the manuscript. A Ojagbemi and AP Okekunle
contributed equally to the manuscript and are joint first authors.
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