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 220 AFRICA
0.89–0.95; p < 0.00001).
Statistical heterogeneity (Fig. 1) was low for studies on heart
disease only (I2 = 0%), CHD only (I2 = 14%), and stroke only (I2
= 36%) but not among studies on cerebral infarction only (I2 =
75%).
Funnel plots (Figs 3B, 4) suggested no evidence of publication
bias and no sole study exerted a significant effect on the sensitivity
of the overall findings of the meta-analysis (Tables 3, 4).
Discussion
In this study, higher intake of GLV was linked to reduced
incidence of all CVD events by 7% and, in particular, it was
inversely related to the incidence of cerebral infarction, CHD,
heart disease and stroke. These findings may suggest a potential
role of GLV intake as a primary-prevention strategy in the
management of CVD.
Similar to our findings, the largest study on stroke among
Africans [the Stroke Investigative Research and Educational
Network (SIREN) study] reported a strong protective dose–
response association such that daily consumption of GLV was
more protective against stroke [odds ratio (OR): 0.27; 95% CI:
0.19–0.38] than weekly consumption (OR: 0.70; 95% CI: 0.52–
0.95), compared to no consumption.52 Earlier systematic reviews
and meta-analyses were broadly focused and generally combined
fruit and vegetables in investigating the effect of these nutritional
modalities on incident CVD events.11,19,20,22,53-58 The uniqueness
of our study is therefore in the deconstruction of the specific
contribution of GLV on CVD. Also, our approach offered vital
insights into the potential roles of GLV in the occurrence of
CVD subtypes.
Although the exact mechanism of the protective effect of
GLV is not well understood, some constituents of GLV are likely
to confer small-to-moderate but clinically important protection
against CVD.25 For example, VitaminB9, micronutrients and other
Table 3. Sensitivity analysis of pooled RR stratified
by categories of CVD events in the meta-analysis
Studies in the meta-analysis I2 (%)
Pooled RR
(95% CI) p-value
All studies 36 0.93 (0.92–0.95) < 0.00001
Cerebral infarction only 28 0.94 (0.92–0.95) < 0.00001
Cerebal and subarachnoid haemor-
rhage only
43 0.93 (0.92–0.95) < 0.00001
Coronary heart disease only 41 0.94 (0.92–0.96) < 0.00001
Heart disease only 40 0.93 (0.92–0.95) < 0.00001
Stroke only 40 0.93 (0.92–0.95) < 0.00001
Composite CVD events 22 0.93 (0.91–0.94) < 0.00001
Table 4. Sensitivity analysis of pooled RR of all
cohort studies included in the meta-analysis
Studies in the meta-analysis
I2
(%)
Pooled RR
(95% CI) p-value
Cerebral infarction only
All studies 75 0.92 (0.88–0.96) 0.0003
Larsson et al. 2013_Cerebral infarction 0 0.85 (0.79–0.91) < 0.00001
Sauvaget et al. 2003_Cerebral infarc-
tion_men only
76 0.94 (0.89–0.99) 0.03
Sauvaget et al. 2003_Cerebral infarc-
tion_women only
84 0.93 (0.88–0.98) 0.007
Cerebal and subarachnoid haemorrhage
only
All studies 0 0.95 (0.86–1.04) 0.25
Larsson et al. 2013_Cerebral haemor-
rhage
0 0.97 (0.87–1.08) 0.57
Larsson et al. 2013_Subarachnoid
haemorrhage
0 0.93 (0.84–1.02) 0.12
Sauvaget et al. 2003_Cerebral haemor-
rhage_women only
0 0.96 (0.85–1.08) 0.48
Sauvaget et al. 2003_Cerebral haemor-
rhage_men only
13 0.95 (0.85–1.05) 0.30
Coronary heart disease only
All studies 14 0.92 (0.90–0.95) < 0.00001
Bendinelli et al. 2010_CHD 0 0.93 (0.90–0.95) < 0.00001
Bhupathiraju et al. 2013_CHD 36 0.93 (0.89–0.97) 0.0003
Blekkenhorst et al. 2017_CHD 4 0.91 (0.88–0.94) < 0.00001
Joshipura et al. 2001_CHD 23 0.93 (0.90–0.96) < 0.00001
Oude Griep et al. 2011_CHD 36 0.92 (0.90–0.95) < 0.00001
Heart disease only
All studies 0 0.93 (0.87–0.99) 0.02
Rautiainen et al. 2014_Heart failure – 0.87 (0.73–1.03) 0.10
Wang et al. 2016_Heart disease – 0.94 (0.88–1.00) 0.05
Stroke only
All studies 36 0.93 (0.90–0.96) < 0.0001
Johnsen et al. 2003_Ischemic stroke 45 0.93 (0.90–0.97) < 0.0001
Joshipura et al. 1999_Ischemic stroke 44 0.93 (0.90–0.97) 0.0003
Larsson et al. 2013_all stroke 22 0.91 (0.87–0.95) < 0.0001
Oude Griep et al. 2011_all stroke 14 0.92 (0.89–0.96) < 0.0001
Sauvaget et al. 2003_Stroke_men only 41 0.94 (0.90–0.97) 0.0005
Sauvaget et al. 2003_Stroke_women
only
45 0.93 (0.90–0.97) 0.0007
Wang et al. 2016_Stroke 24 0.94 (0.90–0.97) 0.0003
Composite CVD events
All studies 64 0.95 (0.93–0.98) 0.0006
Buil-Cosiales et al. 2016_all CVD 75 0.95 (0.93–0.98) 0.001
Gaziano et al. 1995_all CVD 30 0.96 (0.93–0.98) 0.003
Hung et al. 2004_all CVD 73 0.96 (0.90–1.02) 0.17
Joshipura et al. 2008_Ischemic CVD 72 0.95 (0.93–0.98) 0.0009
Takachi et al. 2007_all CVD 59 0.94 (0.91–0.97) < 0.0001
Subgroups
Cerebral Infarction only
Cerebal&Subarachnoid Haemorrhage only
Coronary Heart Disease only
Heart Disease only
Stroke only
Composite CVD events
0.7 0.85 1 1.2 1.5
0
0.05
0.1
0.15
0.2
RR
SE(log[RR])
Fig. 4. Funnel plots assessing publication bias in the meta-
analysis.