The effect of reallocating sedentary behavior to physical activity on non-alcoholic fatty liver disease: a prospective study based on objectively measured behaviors

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K17930
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 59040:Nutrition science and health science-related
• Research Institution: Yamaguchi Prefectural University
• Principal Investigator: TSUNODA Kenji 山口県立大学, 社会福祉学部, 准教授 (90718909)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 運動 / 座位行動 / 脂肪肝 / 非アルコール性脂肪肝 / 肥満 / 加速度計 / 人間ドック / 健診

Outline of Final Research Achievements

In a cross-sectional analysis, the odds of non-alcoholic fatty liver disease (NAFLD) in moderate- to vigorous-intensity physical activity (MVPA) rapidly decreased to approximately 1800 MET-min/week and then moderately declined. Although sedentary behavior (SB) was significantly associated with NAFLD in the body mass index (BMI)-unadjusted model, a significant association was not observed in the BMI-adjusted model. These results suggest that part of the association between SB and NAFLD was mediated or confounded by obesity. The compositional isotemporal substitution revealed that reallocating 60 min/day of SB to MVPA decreased the odds of NAFLD by 22%. In a 4-year follow-up study, total physical activity significantly decreased the incident risk of NAFLD, whereas SB significantly increased it. A reallocating model estimated that replacing SB with MVPA is the most promising behavioral replacement for the prevention of NAFLD.

Free Research Field

疫学　スポーツ科学

Academic Significance and Societal Importance of the Research Achievements

身体活動は非アルコール性脂肪肝疾患（NAFLD）の発症リスクを減少させる一方で、座位行動は同リスクを増加させることがわかった。活動種類別の検討により、NAFLDの予防効果は、特に中高強度活動に期待されることがわかったが、一日の行動時間に占める同活動の割合は5.4％とわずかであり、大半を座位行動が占めていた。行動置換に着目した分析では、NAFLDの予防においては、座位行動を減らし中高強度活動に充てることが最も有効な行動置換であり、1時間の置換では同リスクが約2割減ることが期待された。NAFLDの予防では、少しずつであっても中高強度活動を生活に取り入れることが重要であると示唆された。