Background
There is evidence from observational studies that whole grai
ns can have a beneficial effect on risk for cardiovascular disease (C
VD).
Earlier versions of this review found mainly short-term inte
rvention studies. There are now longer-term randomised contr
olled trials
(RCTs) available. This is an update and expansion of the origi
nal review conducted in 2007.
Objectives
The aim of this systematic review was to assess the effect of wh
ole grain foods or diets on total mortality, cardiovascular ev
ents, and
cardiovascular risk factors (blood lipids, blood pressure) in h
ealthy people or people who have established cardiovascular d
isease or
related risk factors, using all eligible RCTs.
Search methods
We searched CENTRAL (Issue 8, 2016) in the Cochrane Library, MED
LINE (1946 to 31 August 2016), Embase (1980 to week 35
2016), and CINAHL Plus (1937 to 31 August 2016) on 31 August 2016
. We also searched ClinicalTrials.gov on 5 July 2017 and the
World Health Organization International Clinical Trials Re
gistry Platform (WHO ICTRP) on 6 July 2017. We checked reference l
ists
of relevant articles and applied no language restrictions.
Selection criteria
We selected RCTs assessing the effects of whole grain foods or d
iets containing whole grains compared to foods or diets with a s
imilar
composition, over a minimum of 12 weeks, on cardiovascular dise
ase and related risk factors. Eligible for inclusion were heal
thy adults,
those at increased risk of CVD, or those previously diagnosed
with CVD.
Data collection and analysis
Two review authors independently selected studies. Data wer
e extracted and quality-checked by one review author and checked by
a second review author. A second review author checked the analys
es. We assessed treatment effect using mean difference in a fixe
d-
effect model and heterogeneity using the I
2
statistic and the Chi
2
test of heterogeneity. We assessed the overall quality of ev
idence using
GRADE with GRADEpro software.