PLoS One. 2016; 11(2): e0150140.
Published online 2016 Feb 25. doi: 10.1371/journal.pone.0150140
PMCID: PMC4767213
Pratibha V. Nerurkar, Editor
Abstract
Background
Over
the last decade academic interest in the prevalence and nature of
herbal medicines use by pregnant women has increased significantly. Such
data are usually collected by means of an administered questionnaire
survey, however a key methodological limitation using this approach is
the need to clearly define the scope of ‘herbals’ to be investigated.
The majority of published studies in this area neither define ‘herbals’
nor provide a detailed checklist naming specific ‘herbals’ and CAM
modalities, which limits inter-study comparison, generalisability and
the potential for meta-analyses. The aim of this study was to compare
the self-reported use of herbs, herbal medicines and herbal products
using two different approaches implemented in succession.
Methods
Cross-sectional
questionnaire surveys of women attending for their mid-trimester scan
or attending the postnatal unit following live birth at the Royal
Aberdeen Maternity Hospital, North-East Scotland. The questionnaire
utilised two approaches to collect data on ‘herbals’ use, a single
closed yes/no answer to the question “have you used herbs, herbal
medicines and herbal products in the last three months”; and a request
to tick which of a list of 40 ‘herbals’ they had used in the same time
period.
Results
A
total of 889 responses were obtained of which 4.3% (38) answered ‘yes’
to herbal use via the closed question. However, using the checklist 39%
(350) of respondents reported the use of one or more specific ‘herbals’
(p<0.0001). The 312 respondents who reported ‘no’ to ‘herbals’ use
via the closed question but “yes” via the checklist consumed a total of
20 different ‘herbals’ (median 1, interquartile range 1–2, range 1–6).
Conclusions
This
study demonstrates that the use of a single closed question asking
about the use of ‘herbals’, as frequently reported in published studies,
may not yield valid data resulting in a gross underestimation of actual
use.
Introduction
The
increasing use of herbs, herbal medicines and herbal products
(‘herbals’) to maintain health and treat a variety of medical conditions
has generated significant academic interest. Since 2005 there has been a
20 fold increase in the number of systematic reviews and a two fold
increase in prevalence surveys relating to ‘herbals’ published in peer
reviewed journals (See Fig 1).
Number
of hits over the last 10 years for Medline title search for ‘systematic
review’ and ‘herb*’ and number of hits over the last 10 years for
Medline abstract search of (‘questionnaire*’ or ‘survey*’) ...
Given
the paucity of robust data regarding the safety, efficacy and potential
for interaction with prescribed medication, the widespread use of
‘herbals’ by the public should be of interest to the medical profession
and regulatory authorities [1–4].
Of particular concern may be use by pregnant women, who may endanger
both their own health and that of their baby via potential herbs-drug
interactions or direct toxicity from active herbal ingredients or toxic
adulterants [5–16].
A
key limitation of most published studies reporting the use of ‘herbals’
is the failure to clearly define the scope of ‘herbals’ investigated. A
recent systematic review of prevalence studies reporting the use of
‘herbals’ and other complementary and alternative medicine (CAM)
modalities by pregnant women, identified that appropriate definitions of
‘herbals’ and CAMs were only provided in twelve of twenty-two studies [17].
Furthermore, detailed checklists naming specific ‘herbals’ and CAM
modalities were described in only ten studies, with little uniformity in
content across studies [17]. These failings limit direct inter-study comparison, generalisability, data pooling and the potential for meta-analyses.
This
situation is not helped by the complex and major differences in the
terms and definitions of ‘herbals’ originating from different regulatory
authorities [18–20] (Table 1).
In addition there are differences between countries in the regulatory
classification of ‘herbals’. For instance in the United Kingdom some
herbal products are classified as food supplements or cosmetics and
others as medicines, while in the USA all herbal medicines and products
are described as ‘Dietary Supplements’ [21–23].
Definitions
of herbs, herbal medicines, herbal products and Dietary Supplements
used by the World Health Organisation, Medicines and Healthcare products
Regulatory Agency (MHRA, United Kingdom) and the Food and Drug
Administration (FDA, United States ...
As
the majority of studies assessing the use of ‘herbals’ use a
questionnaire based approach, it is essential that research participants
clearly understand and correctly interpret the questions asked.
Therefore terms used in the questionnaire should be explicitly defined
to ensure the collection of valid data.
In an attempt
to standardise data collection and reporting in CAM related studies,
Quandt et al described the development of a CAM questionnaire (I-CAM-Q)
to assess self-reported CAM use [24, 25].
The I-CAM-Q has four sections covering: visits to health care
providers; complementary treatments received from physicians; use of
herbal medicine and dietary supplements; and self-help practices.
However, there is little specific reference to ‘herbals’ other than:
‘have you visited a herbalist in the last 12 months?’; ‘have you
received herbs from a physician in the last 12 months?’ and ‘list up to
three herbs/herbal medicines you have used in the last 12 months’. Of
note there is inconsistency in the use of the terms ‘herbs’ and ‘herbal
medicines’, there is no definition of these terms and there is no list
provided of specific ‘herbals’ from which respondents may select. These
are major issues which may impact the internal validity of the data.
Therefore
the aim of our research was to assess the potential for differences in
self-reported use of ‘herbals’ using two different questioning
approaches; single closed question and a list of specific ‘herbals’
administered consecutively.
Methods
Data
assessing the use of CAM collected from women (332) attending for their
mid-trimester (18–21 weeks) scan and women with a live birth admitted
to the postnatal unit (557) at the Royal Aberdeen Maternity Hospital,
North-East Scotland were combined. Data collection was completed in 2012
and study methods have been reported in detail elsewhere [26, 27]; brief study details are given for completeness.
Questionnaires
were based on the findings of our systematic review assessing the
quality of study methodologies used to derive data reporting CAM use
during pregnancy ([17], S1 Questionnaire].
The questionnaire was written in English only and tested for face and
content validity by a panel of researchers, healthcare professionals,
pregnant and postpartum women prior to piloting. Amongst other items,
the questionnaire utilised two different approaches to collect data on
‘herbals’ used.
The first of these was one closed
question, which asked the participant to tick all of a possible 23
different Complementary and Alternative Therapies which they had used (S1 Table
of Complementary and Alternative Therapies). In the antenatal and
postnatal studies participants were asked to: “Please tell us if you
have used any of the following Complementary and Alternative Therapies
during the last three months?” The question was followed by the request
to “Please tick all Complementary and Alternative Therapies that you
have used. If you haven’t heard of some of the names before, don’t
worry. For each of the Complementary and Alternative Therapies you have
used, please tell us why you used it and how you heard about it (doctor,
pharmacists, midwife, family friend, internet, magazine)”. At a later
stage in the questionnaire, participants were presented with an
extensive list (sourced from the Medicines and Healthcare products
Regulatory Agency (MHRA, UK)) of 40 ‘herbals’ [28] (S2 Table
of Herbal and Natural Products) and asked in the antenatal and
postnatal studies to “Please tell us if you have used any of the
following Herbal and Natural Products during the last three months?; The
question was then followed by the request to “Please tick all Herbal
and Natural Products that you have used. If you haven’t heard of some of
the names before, don’t worry. For each of the Herbal and Natural
Products you have used, please tell us why you used it and how you heard
about it (doctor, pharmacists, midwife, family friend, internet,
magazine).
Data were analysed using
descriptive statistics and a two tailed Pearson’s Chi square test to
determine associations between the two different question approaches and
the proportion answering yes to ‘herbals’ use. A P value <0.05 was
considered statistically significant.
Ethics Statement
This
research was approved by National Health Service North of Scotland
Research Ethics Committee and National Health Service Grampian Research
and Development Committee on June 27, 2011 (REC 11/ AL/0094). As the
Ethics Committee required the survey questionnaires to be fully
anonymous and returned directly by respondents in post-paid envelopes
with no record of identifiable data, oral rather than written consent to
participate was deemed appropriate.
Results
Eight
hundred and eighty-nine respondents completed the questionnaire giving
an overall response rate was 71%. Respondent demographics are reported
in Table 2.
Of 889 respondents, only 4.3% (38) reported use of ‘herbals’ via the
closed question. However, using the detailed list 39% (350) of
respondents reported the use of one or more specific ‘herbals’.
Therefore 312 (35%) respondents who reported ‘no’ to ‘herbals’ use via
the closed question actually reported “yes” to the use of herbs, herbal
medicines or herbal products via the detailed list. This difference is
statistically significant, p<0.0001.
Study population demographics (n = 889).
The
312 respondents who initially reported “no” actually consumed or used a
total of 20 different ‘herbals’ (median 1, interquartile range 1–2,
range 1–6) (See Fig 2).
Bar
chart of the actual number of different herbs, herbal medicines and
herbal products taken or used by those responding ‘no’ to the closed
question “have you used herbs, herbal medicines or herbal products in
the last three months” ...
The
most frequently reported ‘herbals’ used were: raspberry tea or capsules
61% (126); ginger 29% (89); cranberry 22% (70); chamomile 16% (49);
peppermint 12% (36); eucalyptus 8.3% (26); aloe 6.7% (21); grapefruit
6.4% (20); senna 5.4% (17); echinacea 4.5% (14); garlic beyond cooking
3.5% (11); ginseng 1.3% (4); 0.6% (2) each for aconite, nettle root,
dong quai; 0.3% (1) each for barberry, bee pollen, blue cohosh, ginkgo
biloba, and kava.
Binary logistic
regression did not identify and significant differences, in terms of
demographics, between the two study patient cohorts.
Discussion
Our key finding is that using the closed question approach, as recommended in the I-CAM-Q [24, 25],
grossly underestimated the true use of ‘herbals’ by the public. However
employing a detailed list of ‘herbals’ generated a significant tenfold
increase in the number of individuals reporting actual use.
To
our knowledge this is the first study to compare two different
approaches administered consecutively to the same cohort to determine
the self-reported use of ‘herbals’.
In light of these
findings there are key implications for the interpretation and
generalizability for much of the research published in this area. It
should not be surprising that data reported for the use of CAM
modalities and ‘herbals’ during pregnancy are highly variable given that
less than half of published prevalence studies described detailed
checklists [17].
Of note, the I-CAM-Q asks respondents to name up to three herbs/herbal
medicines taken or used in the past 12 months, therefore assuming that
respondents can interpret the terms herbs and herbal medicines, and are
able to categorise accordingly. Our data provide robust evidence that
such an approach is likely to yield a gross and highly significant
underestimate of true prevalence, threatening the internal validity of
the data.
Population surveys such as the I-CAM-Q are
routinely used to gain a picture of public practice or belief; however
it is clear from the results of this study that two simple questions,
which might at first glance be expected to give similar results, gave
rise to significantly different responses. Although writing survey
questions may initially appear simple the current literature would
suggest otherwise [29–31].
The question setter must not only have a clear idea of the question
intent and the likely responses, but also ensure that questions are
written using language which the respondent can understand and process
as intended [29–31].
Failure to follow the basic principles for questionnaire design and
item writing described in the literature will inevitably give rise to
misleading or erroneous survey results.
To ensure
accurate and robust reporting of ‘herbals’ use during pregnancy the use
of a detailed list is clearly necessary, however this may be problematic
given that the number of available ‘herbals’ is increasing [32].
The development and application of specific checklists will require
regular review and updating to acknowledge regional and temporal
variability [32, 33] in ‘herbals’ use.
Although
many ‘herbals’ have been used for centuries, underestimating the level
of use during pregnancy is of clinical importance given that several of
these agents have been directly associated with or have the potential to
cause both maternal and fetal harm [5–16, 34–39].
Strengths and Limitations
A
key strength of this study is the consecutive administration of two
different approaches to identify ‘herbals’ use in the same population.
A
possible limitation however is the use of a study population in the
North of Scotland, which may limit the generalizability of the findings.
However our study population was relatively diverse in terms of
ethnicity, parity and health status hence there is no reason to suspect
that the outcome would be different in other populations. It is also
possible that poor health literacy may have contributed to the
significant differences we observed, however both approaches were
administered concurrently to the study cohort and our population was
relatively well educated, with over three quarters reporting a college
or university education. Therefore it is unlikely that poor health
literacy was responsible for the differences we observed between the
approaches used.
Conclusion
This study has demonstrated the need to ensure that detailed checklists of ‘herbals’ are used in all prevalence studies.
Our
findings may also have relevance for the practicing clinician who
should adopt detailed checklists when asking about a patient’s use of
‘herbals’.
Supporting Information
S1 Questionnaire
Exemplar Antenatal CAM in Pregnancy Questionnaire.
(DOC)
Click here for additional data file.(202K, doc)
S1 Table
Table of Complementary and Alternative Therapies.
Complementary
and Alternative Therapies listed for the Question “Please tell us if
you have used any of the following Complementary and Alternative
Therapies?”
(DOCX)
Click here for additional data file.(13K, docx)
S2 Table
Table of Herbal Medicines and Products.
Herbal
Medicines and Products listed for the Question “Please tell us if you
have used any of the following Herbal and Natural Products?
(DOCX)
Click here for additional data file.(14K, docx)
Funding Statement
This work was funded from internal institutional resource. Prof James McLay is employed by the University of Aberdeen, Prof Derek Stewart is employed by the Robert Gordon University, Drs A.R. Pallivalappila and M. AL Hail are employed by the Hamad Medical Corporation and Drs A. Shetty and B. Pande are employed by NHS Scotland. None of the institutional funders had a role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Data Availability
All relevant data are within the paper and its Supporting Information files.
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