Effectiveness of Horticultural Therapy in Older Adults without Dementia: A Systematic Review and Meta-Analysis

Objectives

Horticultural therapy (HT) has garnered growing interest because of its psychological and physical benefits. Previous reviews have demonstrated its therapeutic effects in older adults with cognitive impairment or mental illnesses. However, its impact on older adults without dementia has not been synthesized. This systematic review studied the effects of HT on the physical and psychosocial functions of older adults without dementia.

Design

Systematic review and meta-analysis.

Settings and Participants

Older adults without dementia ≥60 years of age.

Methods

Randomized controlled trials and quasi-experimental studies were systematically searched in 7 databases. The Cochrane Risk of Bias Tool version 2 and the Risk of Bias in Non-randomized Studies of Interventions tool were used to assess study quality. A random-effects meta-analysis with Hedges' g was conducted to estimate the effect size, and Cochran's Q test and I² were used to evaluate heterogeneity. The Grading of Recommendations Assessment, Development, and Evaluation approach was applied to determine the overall quality of evidence.

Results

Twenty-seven studies, including 11 randomized controlled trials and 16 quasi-experimental studies comprising 1629 older adults from 11 countries, were included. HT tended to improve psychosocial outcomes in older adults, particularly in terms of self-efficacy (g = 0.52; 95% CI, 0.26-0.79) and self-esteem (g = 0.52; 95% CI, 0.26-0.79). In terms of physical benefits, HT appeared to have a greater impact on aerobic endurance, with a large effect size (g = 0.84; 95% CI, 0.54-1.15), compared to agility, which showed a smaller effect size (g = 0.45; 95% CI, −0.90 to −0.01).

Conclusions and Implications

This review demonstrated that HT could provide psychosocial and physical benefits to older adults without dementia. These benefits include slight improvements in self-efficacy, self-esteem, aerobic endurance, and agility. However, the certainty of this evidence is very low due to the quasi-experimental design and potential bias in outcome measurements. Further research with well-designed clinical trials is necessary to confirm its effectiveness.