感謝を中心とする宗教的ライフスタイルはナチュラルキラー細胞活性と主観的健康感を高める可能性がある （A Religious Life Style Centered on Gratitude may Influence on Natural Killer Cell Activity and Subjective Well-Being）
Objectives: The aim of this pilot study is to assess the effect of religious life styles on natural killer (NK) cell activity and psychological status.
Design and Outcome Measures: Among some kinds of remarkable religious life styles, we focused on gratitude. Thirty-one religious subjects (average age, 64.5±6.6years) were recruited and instructed to recollect memories from past to present for a 1-month period by using 3 themes of Naikan therapy. Blood sampling and psychological measurements were performed pre-and post-recollection. Blood sampling was repeated after 3 and 4 months (control period).
Results: (i) A significant improvement in NK cell activity was observed after the 1-month recollection period (average, 34.3%-38.0%; p=0.028), while no improvement was observed in the control period (average, 34.4%-35.7%; p=0.261). (ii) A significant elevation in NK cell activity (average, 35.2%-40.6%; p=0.009) and a positive affect in WHO Subjective Wellbeing Inventory (WHO-SUBI) (average, 42.8144.2; p=0.049) was observed in participants who reported a strong feeling of gratitude, but not in those who reported moderate or no feelings of gratitude.
Conclusion: This is the first study demonstrating the effect of gratitude in improving NK cell activity and positive affect in subjective well-being.
