The Effect of Evening Primrose Oil Capsule on Hot Flashes and Night Sweats in Postmenopausal Women: A Single-Blind Randomized Controlled Trial
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
https://doi.org/10.6118/jmm.20033
J Menopausal Med 2021;27:8-14
pISSN: 2288-6478, eISSN: 2288-6761
ORIGINAL ARTICLE
The Effect of Evening Primrose Oil Capsule on Hot Flashes and
Night Sweats in Postmenopausal Women: A Single-Blind
Randomized Controlled Trial
Farideh Kazemi1, Seyedeh Zahra Masoumi1, Arezoo Shayan1, Khodayar Oshvandi2
1
Department of Midwifery and Reproductive Health, Mother and Child Care Research Center, School of Nursing and Midwifery, Hamadan
University of Medical Sciences, Hamadan, Iran, 2Department of Nursing, Mother and Child Care Research Center, School of Nursing and
Midwifery, Hamadan University of Medical Sciences, Hamadan, Iran
Objectives: Menopause is associated with complications that could decline women’s health during this period. Therefore, some of its
complications, such as hot flashes and night sweats, must be treated or alleviated.
Methods: This randomized controlled trial included postmenopausal women who were referred to health centers in Hamadan from May
2018 to April 2019. The hot flash and night sweat questionnaires were completed by the researcher a week before and 8 weeks after
the intervention. The intervention group took one capsule (1,000 mg) of evening primrose oil twice daily, while the control group received
the same amount of placebo. Finally, the results were analyzed using Stata 13.
Results: The mean scores of duration, frequency, and severity of hot flashes did not significantly decrease in both groups after the
intervention compared with before the intervention, and no statistically significant difference was observed (P > 0.05). However, the
intervention group had lower frequency and severity of night sweats after the intervention than the control group, with statistically
significant differences (P < 0.05).
Conclusions: Evening primrose oil effectively decreased the frequency and severity of night sweats.
Key Words: Evening primrose oil, Hot flashes, Postmenopause, Sweat
INTRODUCTION pain, palpitations, sleep disturbances, restlessness, and
urinary symptoms [2,3].
Menopause is an evolutionary female stage that is Hot flashes and night sweats are the most common
experienced by all women at an older age and exposes and annoying consequences that can affect enjoying
women to a wide range of variations. According to the work and social activities, leisure time, mood, con-
World Health Organization (WHO), menopause oc- centration, communication with others, sexual activ-
curs 12 months after amenorrhea and between the ages ity, enjoyment of life, and the quality of life. The word
of 45 and 55 years [1]. “hot flash” describes the sudden onset of redness of the
Menopause and lower estrogen levels during meno- scalp, neck, and chest, which is accompanied by a feel-
pause are associated with some side effects that can ing of intense heat in the body and occasionally ends
affect a woman’s quality of life and weaken her health in severe sweats. These symptoms are more frequent at
and well-being. The symptoms that women experience night and cause night sweats and sleep disorders [4].
during this period include night sweats, osteoporosis, During menopause, the production of hormones
vaginal dryness, dyspareunia, moral fluctuations, joint from the ovaries stops, resulting in a significant reduc-
Received: October 21, 2020 Revised: February 11, 2021 Accepted: March 2, 2021
Address for Correspondence: Seyedeh Zahra Masoumi, Department of Midwifery and Reproductive Health, Mother and Child Care Research
Center, School of Nursing and Midwifery, Hamadan University of Medical Sciences, Shahid Fahmideh Ave., Hamadan 6517838695, Iran
Tel: +98-9183129058, E-mail: Zahramid2001@gmail.com, ORCID: https://orcid.org/0000-0002-2045-3707
Copyright © by The Korean Society of Menopause
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/).
8Effect of Evening Primrose Capsule in Postmenopause
tion in the circulating estrogen level. A clinical study The minimum required sample size in each group was
evaluated the effects of complementary therapies on the 85 and a total of 170 people were examined in this trial.
treatment of menopausal symptoms [5]. A hormone
replacement therapy with estrogen and progesterone Participants
is the treatment which is currently used to alleviate the Inclusion criteria included at least a year after the last
symptoms of hot flashes and sweating in postmeno- menstrual cessation, no acute and chronic illnesses,
pausal women. The complications of hormone therapy no herbal medication since three months before the
at this age include negative effects on lipids and lipase intervention, no previous allergy to medicinal herbs,
activity, increased risk of stroke, breast and endometrial affliction from or a history of breast cancer and genital
cancer, thromboembolic disorders, liver and Alzheim- cancers. Exclusion criteria included acute illnesses dur-
er’s problems. Like all other chemical treatments, this ing the follow-up and inappropriate drug use during
treatment is contraindicated in some people and others the follow-up that was monitored by the researcher us-
are not satisfied with its use [6]. ing the weekly telephone follow-up.
According to the WHO, 80% of the world’s population Permission was obtained from the Hamadan Health
uses herbal compounds for treatment [7]. Medicinal Center and the Ethics Committee of Hamadan Uni-
herbs as alternative therapies, and estrogenic herbs, versity of Medical Sciences to conduct a research proj-
among them, are the most desirable treatments for ect (No. IR.UMSHA.REC.1396.822), and the written
reducing and treating menopausal symptoms in post- informed consent was obtained from all patients. A
menopausal women [8]. Phytoestrogens are estrogen- total of eight clinics were randomly selected from com-
like compounds present in plant products that are prehensive health centers in Hamadan and assigned to
found in the bile, urine, semen, stool, and the blood of intervention (n = 4) and control (n = 4) groups. Eligible
humans or animals. The evening primrose oil is one of women signed a study consent form. Both groups were
the most important plant phytoestrogens. This plant randomly allocated to four blocks (Fig. 1). It should
belongs to the family Onagraceae, which has various be noted that each participant was then given a closed
effects on menopausal vasomotor symptoms, symp- packet based on the sequence containing either eve-
tomatic relief of psoriasis and premenstrual syndrome, ning primrose oil or a placebo. The drugs were placed
and the inhibition of platelet aggregation [9,10]. Ac- in some opaque closed pockets and then coded for
cording to some studies, evening primrose is effective sequencing sequences, respectively. The present study
in relieving the symptoms of menopausal vasomotor. was single-blind, and the researcher was to the study.
Given the above-mentioned introduction, the pres- First, medicines were coded and then delivered by
ent study aimed to investigate the effect of the evening someone who did not know about the types of medica-
primrose oil capsule on hot flashes and night sweats in tion.
postmenopausal women.
Instruments
MATERIALS AND METHODS The researcher-made demographic questionnaire and
the hot flash and night sweat questionnaire were com-
Study design pleted by the researcher. Wiklund Vasomotor Symptom
This randomized clinical trial was performed in Subscale score was used to measure hot flashes and
health centers of Hamadan from May 2018 to April night sweats. This instrument was developed by the U.S.
2019. Food and Drug Administration. The volunteers could
report the duration, severity, and frequency of hot
Determination of sample size flashes during 24 hours per week. For each hot flash, a
The required values for determining the sample size mark was recorded in the special column after its oc-
were calculated according to a study by Sadeghi et al. currence.
[11] according to the following formula: The intensity of hot flashes was classified into mild (a
score of 1), moderate (2), and severe (3) grades repre-
(σ12 + σ22)(z 1– + z 1–β)2
α
senting a sense of heat without sweating, a sense of heat
n=
2
(μ1 – μ2)2 with sweating, and a sense of heat with sweating and
intervention with normal activities, respectively. The
https://doi.org/10.6118/jmm.20033 9Farideh Kazemi, et al.
Assessed for eligibility (n = 315)
Excluded (n = 25)
Not meeting the inclusion
Enrolment criteria (n = 120)
Randomized (n = 170)
Allocated to the Received allocated
Allocation intervention group (n = 85) intervention (n = 85)
Follow-up Lost to follow-up (n = 5) Lost to follow-up (n = 2)
Analysis Analyzed (n = 80) Analyzed (n = 83)
Fig. 1. The process of selecting samples.
duration of hot flashes was also less than 30 seconds, other areas from this region. An oil called ‘huiledon-
30–60 seconds, 1–3 minute(s), 3–5 minutes, and more ager’ is obtained from the seeds of this plant. The oil is
than 5 minutes and was recorded quantitatively. The in- greenish-yellow and is composed of various acids such
tensity of night sweats was classified into mild, moder- as palmitic (6.5%), stearic (1.5%), oleic (11%), linoleic
ate, and severe degrees. The first one indicated that the (72%), alpha-linoleic, gamma-linolenic, and arachi-
night sweat did not wake you up although you found donic acids. The oil is valuable due to its drying proper-
that your clothes or bed were wet when you woke up ties and the existence of gamma-linolenic acid. Several
for another reason. Moderate and severe degrees dem- agents also contribute to the prostaglandin biosynthesis
onstrated that night sweat woke you up, but not enough in this oil. The placebo capsule was also produced simi-
to do anything for and it woke you up and you took lar to the first drug and given to eligible participants.
measures to solve it. All the above-mentioned cases Correct drug use was monitored weekly by the tele-
were included in a table for conveniently completing phone. Questionnaires were completed by participants
hot flash registration forms. The reliability of the tool in both groups before and eight weeks after the study.
was reported in other studies [12,13]. On this scale,
the intensity of night sweats was categorized into mild, Statistical analysis
moderate, and severe degrees. The form was given to The data were analyzed using Stata 13 (StataCorp,
volunteers to complete in case of night sweats in the College Station, TX, USA). The distribution of quanti-
morning and after a night sleep. tative variables was checked using histogram, central-
dispersion indices, and the Shapirovilk test. In addition,
Intervention an independent t -test and Mann–Whitney test were
The intervention was in the form of evening primrose used to compare quantitative demographic and obstet-
oil and placebo consumption twice daily. The evening ric variables with a normal distribution and quantitative
primrose oil is available in 1,000 mg soft capsules in a variables with an abnormal distribution, respectively.
medicine container with a brochure in a cardboard box Further, chi-square and Fisher’s exact tests were applied
in pharmacies (group A). The control group (group to compare variables that were classified into groups.
B) received a placebo. The 1,000 mg evening primrose The transformation was used since the distribution of
oil, which was produced by Barij Essence Pharmaceu- the duration, number, and severity of hot flashes was
tical Company (Mashhad Ardehal, Iran), was used not normal. Accordingly, the distribution of duration
twice a day for eight weeks for treating hot flashes and and the severity of flushing using square transforma-
night sweats. North America is considered as the main tion, along with the number of flushing by applying
source of this plant, and then it has been transferred to inverse square root transformation became near nor-
10 www.e-jmm.orgEffect of Evening Primrose Capsule in Postmenopause
mal. Data analysis related to the main outcome of the the body mass index status among the two groups in-
study was performed by ANOVA/ANCOVA test, and dicated that approximately half of the individuals were
back-transformation was utilized to report the means overweight. There was no statistically significant differ-
in the table. Finally, the data were reported in the origi- ence between the two groups regarding demographic
nal scale. Moreover, Fisher’s exact and chi-square tests characteristics and the two groups were homogeneous
were employed to compare the number and severity of (P > 0.05).
sweating, comorbid symptoms, and sleep disturbance By controlling the effect of pre-intervention scores,
along with night sweats. The significance level was con- the results showed that the duration and frequency of
sidered 0.05. hot flashes between the two groups were not statisti-
cally significant. However, the comparison of the two
RESULTS groups in terms of the severity of hot flashes revealed
that the mean ± standard deviation was 1.9 ± 1.7 and 2.1
Based on the results (Table 1), the mean age of the ± 1.7 in the intervention and placebo groups, respec-
participants and the mean age of the onset of meno- tively, and this decrease was statistically significant (P
pause were 54.7 ± 4.8 years and 55.9 ± 5.2 years, as well = 0.03). Conversely, a Cohen’s d value of 0.13 indicated
as 48.6 ± 5.3 years and 50.1 ± 4.8 years in intervention that the intervention was not effective in reducing the
and placebo groups, respectively. The mean duration severity of hot flashes (Table 2).
of menopause was also higher in the placebo group Based on the comparison of the frequency and inten-
compared to the intervention group. The majority of sity of night sweats in the pre-intervention phase, no
participants in both groups had primary education and statisticallys significant difference was found between
more than 90% were housewives. The comparison of the two groups. After the intervention, 27.5% of partic-
Table 1. Comparison of some demographic characteristics in groups
Variable Evening primrose oil group Placebo group Test statistics P value
Age (y) 54.7 ± 4.8 55.9 ± 5.2 –1.51 0.13a
Age of the onset of menopause (y) 48.6 ± 5.3 50.1 ± 4.8 –1.07 0.28b
Duration of menopause (y) 6.0 ± 5.9 7.0 ± 5.0 –1.63 0.10b
Parity 3 (3, 5) 4 (3, 5) –0.54 0.59a
No. of children alive 3 (2, 4) 4 (3, 5) 0.22 0.82a
Education 0.89 0.93c
Illiterate 16 (18.8) 14 (16.9)
Primary 34 (40.0) 33 (39.8)
High school 15 (17.6) 18 (21.7)
Diploma 15 (17.6) 15 (18.1)
Academic 5 (5.9) 3 (3.6)
Occupation 0.38 0.53c
Employed 5 (6.0) 7 (8.4)
Unemployed 79 (94.0) 76 (91.6)
Body mass index 0.46 0.79c
18.5–24.9 kg/m2 17 (20.0) 16 (19.5)
2
25–29.9 kg/m 49 (57.6) 44 (53.7)
2
≥ 30 kg/m 19 (22.4) 22 (26.8)
Data are presented as mean ± standard deviation, median (Q1, Q3), or number (%).
In the variables with total number less than 85, there was missing data and the participants did not answer the question.
BMI: body mass index.
a
Independent t -test; bMann–Whitney; cchi-square test.
https://doi.org/10.6118/jmm.20033 11Farideh Kazemi, et al.
Table 2. Comparison of duration, frequency, and intensity of hot flashes in participants
Before intervention After intervention Cohen’s db
Variable Group F P valuec
(mean ± SD) (adjusted mean ± SD)a (95% CI)
Duration of hot flashes Evening primrose oil 4.8 ± 0.4 4.1 ± 2.7 0.003 (–0.30, 0.31) 0.01 0.93
Placebo 4.6 ± 0.7 4.1 ± 2.8
Frequency of hot flashes/day Evening primrose oil 8.0 ± 6.0 2.8 ± 4.6 0.06 (–0.24, 0.37) 1.16 0.28
Placebo 6.9 ± 2.4 2.5 ± 4.9
Intensity of hot flashes Evening primrose oil 2.7 ± 0.6 1.9 ± 1.7 0.13 (–0.17, 0.44) 4.54 0.03
Placebo 2.7 ± 0.6 2.1 ± 1.7
The duration score was less than 30 seconds (1), 30–60 seconds (2), 1–3 minute(s) (3), 3–5 minutes (4), and more than 5 minutes (5).
The intensity score was classified into mild (1), moderate (2), and severe (3) grades.
SD: standard deviation, CI: confidence interval.
a
Adjusted for before intervention score; bCohen’s d effect size: 0.2–0.4 considered small, 0.5–0.7 considered moderate, ≥ 0.8 considered large; cANOVA/
ANCOVA.
Table 3. Comparison of the number and intensity of night sweats before and after the intervention between two groups
2
Variable Evaluation time Evening primrose oil (n = 80) Placebo (n = 83) χ P value
Frequent night sweats Before intervention Without 0 (0) 1 (1.2) 0.18a
Low 5 (6.3) 1 (1.2)
Moderate 27 (33.8) 34 (41.0)
High 48 (60.0) 47 (56.6)
After intervention Without 22 (27.5) 0 (0) 79.93 < 0.001
Low 35 (43.8) 6 (7.2)
Moderate 22 (27.5) 44 (53.0)
High 1 (1.3) 33 (39.8)
Intensity of night sweats Before intervention Mild 7 (8.8) 10 (12.0) 1.41 0.49
Moderate 53 (66.3) 58 (96.9)
Severe 20 (25.0) 15 (18.1)
After intervention Mild 38 (47.5) 8 (9.6) 33.46 < 0.001
Moderate 40 (50.0) 60 (72.3)
Severe 2 (2.5) 15 (18.1)
Data are presented as number (%).
In follow-up studies, lost to follow up is unavoidable and because the number of lost was not considerable, the causes were not investigated.
a
Fisher exact test and the rest: chi-square test.
ipants in the intervention group reported no sweating. DISCUSSION
Contrarily, about 40% of those in the placebo group
reported high rates of night sweats during a week. Ad- The results of this study indicated that evening prim-
ditionally, nearly 2.5% and 47.5% of participants of rose oil had no significant effect on relieving the symp-
the intervention group had severe and mild sweating, toms of hot flashes although it was effective in improv-
respectively. However, 9.6% of people in the placebo ing night sweats.
group reported mild sweating. These differences were The evening primrose oil capsule is a drug with phy-
statistically significant (Table 3). toestrogenic properties. Its mechanism in improving
hot flashes and night sweats is unclear although it may
act as an estrogen agonist, and antagonist and through
interaction with the estrogen [14] receptor. Phytoes-
12 www.e-jmm.orgEffect of Evening Primrose Capsule in Postmenopause
trogens act as agonists or antagonists of the estrogen that the evening primrose oil was effective in reducing
receptor and can provide stronger estrogenic effects the frequency and severity of night sweats although it
when the estrogen level is low in the environment and had no significant effect on the relief of hot flash symp-
it, in fact, compensates for the lack of androgen 17 toms. Therefore, this herbal medicine can be useful in
beta-estradiol in menopause. For this reason, many relieving some menopause-associated symptoms.
women use phytoestrogenic family herbs as a supple-
ment and hormone replacement therapy in menopause ACKNOWLEDGMENTS
to improve the symptoms of this period [15].
Based on the findings of the present study, this herbal The authors would like to express their heartiest grati-
drug did not affect the severity, duration, and frequen- tude to the Research Department of Hamadan Univer-
cy of hot flashes, but it was effective on the frequency sity of Medical Sciences and women in the community
and severity of night sweats. Different studies evalu- health centers, whose contributions were vital for con-
ated the effect of phytoestrogenic plants on hot flashes ducting the present study.
in postmenopausal women. In their study, Farzaneh et
al. [16] investigated the frequency, severity, and dura- CONFLICT OF INTEREST
tion of hot flashes in treating 45–59 years old women
using the evening primrose oil capsule and found that No potential conflict of interest relevant to this article
flashing attacks diminished after six weeks. In this was reported.
regard, Motaghi Dastenaie et al. [17] indicated the sig-
nificant effect of the evening primrose oil on reducing REFERENCES
hot flashes in postmenopausal women compared to
women taking the placebo. They also suggested that 1. Rodríguez-Fuentes G, de Oliveira IM, Ogando-Berea H, Otero-
herbal compounds could be used as complementary Gargamala MD. An observational study on the effects of Pilates
therapies in treating menopausal symptoms instead on quality of life in women during menopause. Eur J Integr Med
of some hormonal therapies. The reason for the dis- 2014; 6: 631-6.
crepancy in the results of this study with those of other 2. Hess R, Thurston RC, Hays RD, Chang CC, Dillon SN, Ness RB,
studies regarding the effect of the drug on reducing et al. The impact of menopause on health-related quality of life:
hot flashes may be due to the lower dosage of the drug results from the STRIDE longitudinal study. Qual Life Res 2012;
in our study. In the study of Mehrpooya et al. [18], the 21: 535-44.
evening primrose oil affected the severity of hot flashes 3. Shayan A, Masoumi SZ, Shobeiri F, Tohidi S, Khalili A. Compar-
in menopause while having no significant effect on its ing the effects of Agnugol and metformin on oligomenorrhea in
frequency. In another study, Low Dog [19] reported patients with Polycystic Ovary Syndrome: a randomized clinical
that the evening primrose oil was not effective in reliev- trial. J Clin Diagn Res 2016; 10: QC13-6.
ing menopausal vasomotor symptoms. The results of 4. Taylor HS, Pal L, Sell E. Speroff’s clinical gynecologic endocrinol-
the above-mentioned studies are in line with those of ogy and infertility. Philadelphia: Lippincott Williams & Wilkins;
our study. 2019.
In a systematic review study, Yousefi et al. [20] con- 5. Ghazanfarpour M, Sadeghi R, Abdolahian S, Latifnejad Roud-
cluded that the consumption of evening primrose oil sari R. The efficacy of Iranian herbal medicines in alleviating hot
is effective in reducing the severity and frequency of flashes: a systematic review. Int J Reprod Biomed 2016; 14: 155-66.
sweating in menopause. Another systematic study by 6. Messina M. Soy foods, isoflavones, and the health of postmeno-
Mahboubi [21] highlighted the beneficial effects of the pausal women. Am J Clin Nutr 2014; 100 Suppl 1: 423S-30S.
evening primrose oil on menopausal vasomotor symp- 7. Ekor M. The growing use of herbal medicines: issues relating to
toms. The findings of these studies corroborate with adverse reactions and challenges in monitoring safety. Front Phar-
the results of the present study. Similar to the other macol 2014; 4: 177.
study [22], our findings showed another effect of herbal 8. Estrada-Camarena E, López-Rubalcava C, Valdés- Sustaita B,
medicines in treating the symptoms of diseases. One Azpilcueta-Morales GS, González-Trujano EM. Use of phytoes-
of the limitations of our study is the small sample size, trogens for the treatment of psychiatric symptoms associated with
which reduces the generalizability of the results. menopause transition. In: Rodriguez-Landa JF, Cueto-Escobedo
In general, the results of the present study indicated J, editors. A multidisciplinary look at menopause. IntechOpen;
https://doi.org/10.6118/jmm.20033 13Farideh Kazemi, et al.
2017. pp. 81-109. soy on menopausal hot flashes. CMJA 2012; 5: 52-60.
9. Montserrat-de la Paz S, Fernández-Arche MA, Ángel-Martín M, 16. Farzaneh F, Fatehi S, Sohrabi MR, Alizadeh K. The effect of oral
García-Giménez MD. Phytochemical characterization of potential evening primrose oil on menopausal hot flashes: a randomized
nutraceutical ingredients from Evening Primrose oil (Oenothera clinical trial. Arch Gynecol Obstet 2013; 288: 1075-9.
biennis L.). Phytochem Lett 2014; 8: 158-62. 17. Motaghi Dastenaie B, Safdari F, Raisi Z, Karimian Z. The effect
10. Shobeiri F, Masoumi SZ, Nikravesh A, Heidari Moghadam R, of evening primrose plant on physical symptoms of menopause.
Karami M. The impact of aerobic exercise on quality of life in JBUMS 2017; 19: 34-40.
women with breast cancer: a randomized controlled trial. J Res 18. Mehrpooya M, Rabiee S, Larki-Harchegani A, Fallahian AM, Mo-
Health Sci 2016; 16: 127-32. radi A, Ataei S, et al. A comparative study on the effect of “black
11. Sadeghi A, Bakhshi M, Behboodi Z, Goodarzi S, Haghani H. cohosh” and “evening primrose oil” on menopausal hot flashes. J
Effect of sage extract on hot flashes in postmenopausal women. Educ Health Promot 2018; 7: 36.
CMJA 2013; 2: 324-35. 19. Low Dog T. Menopause: a review of botanical dietary supple-
12. Nahidi F, Zare E, Mojab F, Alavi-Majd H. Effects of licorice on ments. Am J Med 2005; 118 Suppl 12B: 98-108.
relief and recurrence of menopausal hot flashes. Iran J Pharm Res 20. Yousefi Z, Abdollahpour N, Ghazanfarpour M, Sadeghi R, Pour-
2012; 11: 541-8. moghadam N. Impacts of herbal medicines on hot flash: a system-
13. Newton KM, Reed SD, LaCroix AZ, Grothaus LC, Ehrlich K, atic review. J Med Plants 2016; 15: 40-6.
Guiltinan J. Treatment of vasomotor symptoms of menopause 21. Mahboubi M. Evening primrose (Oenothera biennis) oil in man-
with black cohosh, multibotanicals, soy, hormone therapy, or pla- agement of female ailments. J Menopausal Med 2019; 25: 74-82.
cebo: a randomized trial. Ann Intern Med 2006; 145: 869-79. 22. Masoumi Z, Keramat A, Hajiaghaee R. Systematic review on effect
14. Jassim GA. Strategies for managing hot flashes. J Fam Pract 2011; of herbal medicine on pain after perineal episiotomy and cesarean
60: 333-9. cutting. J Med Plants 2011; 10: 1-16.
15. Akbari TN, Davoodabadi FM. Comparative effects of flaxseed,
14 www.e-jmm.orgYou can also read
