A randomized clinical trial of mindfulness training versus a health promotion program: Impact on cognitive and mental health in older immigrants.

Background: Mindfulness-based stress reduction (MBSR) has shown benefits for cognition and stress relief. Enhancing these functions may have a protective role in vulnerable populations, particularly older immigrants who face a higher risk of neurodegenerative disease. However, whether MBSR can have positive effects on cognitive and affective functions in these populations remains understudied. This trial compared the effects of MBSR with a health promotion program (HPP) in older immigrants. Methods: In this single-center, randomized, double-blind controlled trial, 151 Portuguese-speaking older immigrants (≥55 years old) residing in Luxembourg were screened and 89 participants (age range: 55-80, M age: 62.58 years ± 6.08, 72 % women) were randomized to 2-month weekly group interventions of either MBSR (n = 44) or HPP (n = 45). Data were collected at three time points: baseline, immediately after the intervention (post-intervention), and at follow-up, conducted one to three months after the intervention. Executive functioning measures, including Letter-Number Sequencing, Trail Making Test, and Stroop color-word, were the main outcomes. Secondary outcomes included general cognitive functioning, cortisol level, heart rate variability, and self-reported affective and mindfulness states. Results: 75 % of participants in the MBSR group and 53 % in the HPP group completed at least one post-assessment. Linear mixed model analyses showed significant time effects in Letter-Number Sequencing (p = .04), as well as reductions in anxiety (p < .01) and perceived stress (p < .01), with no significant group differences or group × time interactions. These improvements were observed from baseline to post-intervention and still persisted at follow-up. Conclusion: Both interventions positively influenced attention, with the most notable improvements observed in anxiety and perceived stress. These findings suggest that group interventions may have the potential to improve cognitive and affective indicators, regardless of their specific content. Despite their diverse goals, the interventions shared procedural features, such as the organization and delivery of the sessions, which may have contributed to the outcomes observed. This underscores the potential value of well-designed group-based programs in cognitive and affective indicators among vulnerable older adults. While further research is needed, our findings point to the relevance of including these interventions within the realm of promoting healthy aging and dementia prevention.