Chan et al. BMC Geriatrics (2017) 17:192 DOI 10.1186/s12877-017-0588-z STUDYPROTOCOL Open Access Effects of horticultural therapy on elderly’ health: protocol of a randomized controlled trial Hui Yu Chan1, Roger Chun-Man Ho1,2*, Rathi Mahendran1,2, Kheng Siang Ng1, Wilson Wai-San Tam3, Iris Rawtaer1,2, Chay Hoon Tan4, Anis Larbi5, Lei Feng1, Angelia Sia6, Maxel Kian-Wee Ng7, Goh Lee Gan8 and Ee Heok Kua1,2 Abstract Background: Due to a rapidly ageing population in the world, it is increasingly pertinent to promote successful ageing strategies which are cost-effective, easily accessible, and more likely to be acceptable to the elderly. Past research associates exposure to natural environments and horticultural therapy (HT) with positive psychological, social and physical health benefits. This Randomized Controlled Trial (RCT) is designed to evaluate the efficacy of HT in promoting Asian elderly’ mental health, cognitive functioning and physical health. Methods/design: 70 elderly participants aged 60 to 85 years old will be randomized to participate in either the active horticultural therapy group or be in the waitlist control. Sessions will be weekly for 12 weeks, and monthly for 3 months. Mental health will be assessed through self-reports of depressive and anxiety symptomatology, life satisfaction, social connectedness and psychological well-being, collaborated with immunological markers. Outcome measures of cognitive functioning and physical health include neuropsychological tests of cognitive function and basic health screening. Outcomes will be assessed at baseline, 3 months and 6 months post- intervention. Discussion: This RCT comprehensively investigates the efficacy of a non-invasive intervention, HT, in enhancing mental health, cognitive functioning and physical health. The results have tremendous potential for supporting future successful ageing programs and applicability to larger populations. Trial registration: ClinicalTrials.gov NCT02495194. Trial registration date: July 13, 2015. Retrospectively registered. Keywords: Horticultural therapy, Gardening, Elderly, Mental health, Cognitive functioning, Physical health, Randomized controlled trial Background nature has been found to increase positive affect and re- Worldwide, one in every nine people is aged 60 years duction in anger in individuals, as opposed to those in and above, and by 2050 the proportion is expected to in- the urban environment [4]. This may be due to the re- crease to one in every 5 people [1]. In Singapore, there storative effects of nature, such as recovery of directed was a 2.2% increase in the proportion of older persons attention fatigue and stress mitigation [5]. Therefore in aged 65 years and above in the recent 5 years [2]. This recent years, there is burgeoning research on therapies population has greater mental health risks due to per- which tap on the nature’s benefits on human health and ceived social isolation [3]. Amongst the older adults, gar- one of which is horticulture. dening is a popular leisure-time activity and exposure to Definitions of horticultural activities in literature vary in scope from a broad perspective encompassing all forms of * Correspondence: [email protected] exposure to nature and plants, to a more narrow focus on 1 Department of Psychological Medicine, Yong Loo Lin School of Medicine, active engagement with plants. Defined broadly, horticul- National University of Singapore, Singapore, Singapore 2Department of Psychological Medicine, National University Hospital, tural activities have been shown to reduce depression se- Singapore, Singapore verity and rumination in clinically depressed patients as Full list of author information is available at the end of the article © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Chan et al. BMC Geriatrics (2017) 17:192 Page 2 of 10 the garden environment offers a respite from the urban Therefore the aims of this study are to investigate the settings and fascination to them [6]. Notably, besides re- effectiveness of HT in improving the mental, cognitive ducing negative mood (i.e. tension, depression, fatigue, and physical health of the community-dwelling older anger and confusion), horticulture also brings about an in- adults using a RCT design. Based on the existing litera- crease in positive dimension (i.e. vigor/energy) [7]. Simi- ture, it was hypothesized that, as compared to the wait- larly, a 7-week indoor horticulture activity program was list control, participants in the active treatment group found to improve participants’ psychological well-being, will 1) have better mental health, 3) have greater im- as compared to the waitlist control group [8]. Hence, provement of cognitive functioning and 3) have better horticultural activities may be a promising intervention in physical health. In order to have collaborative evidence improving mental health. with measures of psychological health, the immunology An investigation on the efficacy of horticultural activ- of participants will be investigated via blood-based bio- ities in improving mental health, cognitive functioning markers. Notably, past research has found that depres- and physical health is merited for its wider implications. sive symptomatology was associated with elevated levels If proven to be effective, this innovative and cost- of pro-inflammatory cytokines [20] and lower levels of effective intervention could be a nation-wide strategy in trophic factor [21]. health promotion. It has been stated that the healthcare system alone may be limited in promoting public health Methods [9] and that there is a need for public health strategies All procedures involved in this trial will be conducted in to focus on the socio-ecological aspects of health [10]. compliance with the Helsinki declaration and Singapore Therefore, urban parks, which are easily accessible for Guidelines for Good Clinical Practice. The National Uni- community-dwelling individuals, are an ideal resource to versity of Singapore Institutional Review Board (NUS support the promotion of these aspects of well-being. IRB-Reference Code: B-15-016) gave ethical approval. Because the present study is a goal-oriented interven- This paper describes, according to SPIRIT guidelines, tion which seeks to enhance the mental, cognitive and the trial design, setting, intervention and procedures that physical health of the elderly participants, the definition will be undertaken. put forth is adopted: “Horticultural therapy (HT) is a professionally con- Trial design ducted client-centered treatment modality that utilizes This interventional study will be a RCT comparing par- horticulture activities to meet specific therapeutic or re- ticipation in a HT program to being in a waitlist control. habilitative goals of its participants. The focus is to The intervention will lasts for 6 months with 1-h HT maximize social, cognitive, physical and/or psychological sessions during the first 3 months followed by monthly functioning and/or to enhance general health and well- sessions the next 3 months. Outcome assessments will ness (p. 5).” [11]. be conducted at baseline, 3 months and 6 months. The Enhanced with the environmental benefits offered by 3-months follow-up intervals were decided based on a the nature, HT may be a promising intervention in pro- study by Gonzalez et al. which found that participants’ moting public health and critical in prevention work. depressive symptoms declined after 3 months and these However, there is currently a paucity of research on the improvements were maintained in the final 6-month effectiveness of HT in a multi-ethnic Singaporean popu- follow-up [6]. lation as most studies were conducted either on western societies [6, 12, 13] or Japan and Korea [14]. Due to Study participants unique social and cultural specificities, it is inappropriate Seventy elderly will be recruited from a research center to assume that the findings could be generalized to our in the western district of Singapore. All interested and local population. potentially eligible participants will be screened for cog- Furthermore, there are limitations in the existing re- nitive status and other eligibility criteria. search. Most of the other studies either have small sam- English and/or Mandarin-speaking community-dwelling ple sizes [15–17], short intervention duration [8, 18], or participants aged between 60 to 85 years and have a mini- employed the sole use of questionnaires without collab- mum score of 22 and above on the Montreal Cognitive orating evidence from biological data. In addition, a sys- Assessment (MoCA) will be enrolled into the study. The tematic review found that the randomized controlled cut-off score of 22 on MoCA is to select participants who trials (RCT) conducted thus far have poor methodo- have intact cognitive impairment [22]. However, older logical and reporting quality [19]. Further research is adults will be excluded from the study if they have 1) his- therefore needed to determine