Introduction

Aromatherapy is a therapy that uses essential oils from herbs, flowers, and other plants to improve physical, emotional, and mental well-being through inhalation or topical and oral application [1,2]. Aromatherapy has been reported to have positive effects on infections, insomnia, pain, women’s health, and various health conditions [1–6]. One review suggests that aromatherapy can be effective in inducing relaxation, improving pain, and emotional state [7]. Many systematic reviews (SRs) and meta-analyses (MAs) are published in the field of medicine and health [8], and this is no different in evaluating the efficacy of aromatherapy [4]. Evidence of the positive effects of aromatherapy, currently reviewed, has shown beneficial effects on pain [9], dementia [10], cardiovascular disorders [11], and symptoms of cancers [12–14]. While these studies report positive results, many of them have limited evidence. SRs of SRs can improve access to evidence scattered across multiple studies. This protocol aimed to include the effectiveness reported by all SRs that employed aromatherapy studies as a treatment modality for health problems.

Materials and Methods

1. Study registration

This protocol was registered on the International Platform of Registered Systematic Review and Meta-Analysis Protocols (INPLASY) with registration number INPLASY202280089 (https://inplasy.com/inplasy-2022-8-0089).

2. Inclusion criteria

2.1. Types of studies

The SRs or MAs must specifically address the therapeutic efficacy of aromatherapy treatment of any type through different application methods such as inhalation, massage, and bathing and must include evidence from at least two randomized controlled clinical trials. Non-SRs will be excluded, such as other overviews and narrative reviews. The SR or MA must specifically address the efficacy of any type of aromatherapy and include evidence from at least two controlled clinical trials.

2.2. Types of participants

All populations regardless of age, sex, and health conditions will be included.

2.3. Types of interventions and controls

The eligible intervention will be aromatherapy with any type of essential oil to treat participants with massage, bathing, or inhalation in therapeutic purpose. The included control groups will be placebo or no treatment or active controls and drug therapy. Other forms of control will be excluded.

2.4. Type of outcome measures

Outcome measures include SR-reported data on at least one outcome related to target health conditions. Quality of life and adverse events will be included as additional outcomes.

3. Electronic searches

Seven international databases (including PubMed, AMED, EMBASE, the Cochrane Library), and three Korean medical databases (Korean Studies Information, Research Information Service System, KoreaMed), will be searched for relevant MAs and SRs from inception to October 2022. The search terms will be aromatherapy OR essential oil OR aroma inhalation OR lavender OR rose AND systematic review OR meta-analysis.

4. Study selection and data extraction

Two reviewers will independently review study titles and abstracts, select studies, and record their decisions based on predefined criteria. Disagreements in study selection will be resolved through discussion. Documentation and the summary of study selection will be based on a flowchart that conforms to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis [15]. Data on population, intervention, comparison, and outcomes, the number of randomized controlled trials included, summary effect estimates for primary outcomes, overall risk of bias, publication bias, and conclusions (cited from the original paper) will be retrieved from the included studies.

5. Methodological quality

The quality of reporting for each included SR will be critically appraised using the AMSTAR-2 tool [16]. AMSTAR-2 is a 16-item assessment tool to check the quality of a systematic review and establish whether the most important elements are reported.

6. Strategy of data synthesis

Evidence maps are new synthesis tools that involve searching systematically and characterizing existing research on a topic of interest for the identification of knowledge gaps and future research needs [17]. Evidence mapping should be presented in tables describing the characteristics of the included SRs, as well as a graphical representation of the mapping based on bubble plots according to previous publications [18,19]. Each bubble in the graph should represent an included SR. The SR will be grouped into clinical participants which will be created by a reviewer and discussed by the review team. Subgroup analysis by health condition and essential oil type will be performed. Sensitivity analysis will be performed according to the quality of the SR.

7. Ethics

It was not necessary to obtain patient consent and ethical approval for a protocol.

Discussion

This protocol for SRs will provide guidance to collate the current reviewed evidence of aromatherapy in health management which will be based on the qualitative and quantitative syntheses of the included SRs.

Article information

Author Contributions

Conceptualization, formal analysis, writing-original draft: KJK. Conceptualization, formal analysis, methodology, validation, supervision, writing-original draft: MSL.

Conflicts of Interest

Myeong Soo Lee is an Associate Editor of Perspectives on Integrative Medicine but this had no influence in the decision to publish this article.

Ethical Statement

This research did not involve any human or animal experiments.

Data Availability

All relevant data are included in this manuscript.

Funding

This research was funded by the Korea Institute of Oriental Medicine (no.: KSN2022210). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

References

• [1] Buckle J. Clinical aromatherapy: essential oils in healthcare. 3rd ed. Philadelphia (PA), Churchill Livingstone, 2015.
• [2] Farrar AJ, Farrar FC. Clinical aromatherapy. Nurs Clin North Am 2020;55(4):489−504.ArticlePubMedPMC
• [3] Bunse M, Daniels R, Gründemann C, Heilmann J, Kammerer DR, Keusgen M, et al. Essential oils as multicomponent mixtures and their potential for human health and well-being. Front Pharmacol 2022;13:956541. ArticlePubMedPMC
• [4] Koo M. A bibliometric analysis of two decades of aromatherapy research. BMC Res Notes 2017;10(1):46. ArticlePubMedPMCPDF
• [5] Leach MJ, Sangalli M, Breakspear I, Walsh S. Essential oils for agitation in dementia [rELOAD]: A pragmatic, cluster-randomized, placebo-controlled, pilot feasibility trial. Integr Med Res 2021;10(4):100747. ArticlePubMedPMC
• [6] Smith CA, Hill E, Denejkina A, Thornton C, Dahlen HG. The effectiveness and safety of complementary health approaches to managing postpartum pain: A systematic review and meta-analysis. Integr Med Res 2022;11(1):100758. ArticlePubMedPMC
• [7] Lee MS, Choi J, Posadzki P, Ernst E. Aromatherapy for health care: an overview of systematic reviews. Maturitas 2012;71(3):257−60.ArticlePubMed
• [8] Bastian H, Glasziou P, Chalmers I. Seventy-five trials and eleven systematic reviews a day: how will we ever keep up? PLoS Med 2010;7(9):e1000326.. ArticlePubMedPMC
• [9] Nascimento JC, Gonçalves VSS, Souza BRS, Nascimento LdC, Carvalho BMR, Ziegelmann PK, et al. New approaches to the effectiveness of inhalation aromatherapy in controlling painful conditions: A systematic review with meta-analysis. Complement Ther Clin Pract 2022;49:101628. ArticlePubMed
• [10] Mohamadi N, Pourkorrani MHS, Langarizadeh MA, Ranjbartavakoli M, Sharififar F, Asgary S. Evidence for Rosa damascena efficacy in mental disorders in preclinical animal studies and clinical trials: A systematic review. Phytoth Res 2022;36(8):3016−31.ArticlePDF
• [11] AlMohammed HI A, Alanazi N, Maghrabi EF, Alotaibi AM. Role of aromatherapy as a natural complementary and alternative therapy in cardiovascular disease: a comprehensive systematic review. Evid-Based Complement Alternat Med 2022;2022:4543078. PubMedPMC
• [12] Ahn JH, Kim M. Effects of aromatherapy on cancer patients’ sleep and fatigue: a systematic review and meta-analysis. J Integr Complement Med 2022;Epub 2022 Nov 07. [Epub ahead of print].Article
• [13] Li D, Li Y, Bai X, Wang M, Yan J, Cao Y. The Effects of aromatherapy on anxiety and depression in people with cancer: a systematic review and meta-analysis. Front Public Health 2022;10:853056. ArticlePubMedPMC
• [14] Li F, Jiang T, Shi T. Effect of inhalation aromatherapy on physical and psychological problems in cancer patients: systematic review and meta-analysis. J Psychosoc Oncol 2022;40(3):271−87.ArticlePubMed
• [15] Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021;372:n71.. PubMedPMC
• [16] Shea BJ, Reeves BC, Wells G, Thuku M, Hamel C, Moran J, et al. AMSTAR 2: a critical appraisal tool for systematic reviews that include randomised or non-randomised studies of healthcare interventions, or both. BMJ 2017;358:j4008.. ArticlePubMedPMC
• [17] Hetrick SE, Parker AG, Callahan P, Purcell R. Evidence mapping: illustrating an emerging methodology to improve evidence-based practice in youth mental health. J Eval Clin Pract 2010;16(6):1025−30.ArticlePubMed
• [18] Choi TY, Ang L, Ku B, Jun JH, Lee MS. Evidence map of cupping therapy. J Clin Med 2021;10(8):1750. ArticlePubMedPMC
• [19] Choi TY, Jun JH, Lee HW, Yun JM, Joo MC, Lee MS. Traditional Chinese medicine interventions in the rehabilitation of cognitive and motor function in patients with stroke: an overview and evidence map. Front Neurol 2022;13:885095. ArticlePubMedPMC

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References

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