Abstract
Objective
To perform a systematic review and meta-analysis of all randomized, controlled trials
of isoflavone supplementation to determine the efficacy of isoflavone therapy in reducing
the number of daily menopausal flushes.
Methods
A comprehensive search of published studies of isoflavone treatment and menopausal
flushing was undertaken. Studies were selected if they were randomized, were placebo
controlled, provided the number of baseline flushes, the variance in flushes and the
reduction in flushes. Effects for isoflavone treatment compared to control were calculated
and a meta-analysis was performed. Regression analysis, weighted for the size of the
study was performed to investigate the relationship between the dose of isoflavone,
or number of baseline flushes and the reduction in flushes achieved compared to control.
Results
Isoflavone supplementation was found to be associated with a significant reduction
in flushes (effect size −0.28, 95% confidence intervals −0.39 to −0.18, P < 0.0001). Marked heterogeneity was found between the studies, but the effect remained
significant when analyzed using a random effects model (delta = −0.49, 95% confidence intervals −0.81 to −0.17, P = 0.001). The percentage reduction in flushes was significantly related to the number
of baseline flushes per day and the dose of isoflavone studied (β = −0.49 and −0.26, respectively, both P < 0.0001).
Conclusions
These results suggest that isoflavone supplementation may produce a slight to modest
reduction the number of daily flushes in menopausal women and that the benefit may
be more apparent in women experiencing a high number of flushes per day.
Keywords
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Article info
Publication history
Accepted:
March 25,
2006
Received in revised form:
March 22,
2006
Received:
December 28,
2005
Identification
Copyright
© 2006 Elsevier Ireland Ltd. Published by Elsevier Inc. All rights reserved.
