2026-09-10 ロードアイランド大学（URI）
＜関連情報＞
- https://www.uri.edu/news/2026/09/uri-study-reveals-how-waist-size-and-body-mass-index-are-associated-with-mortality-in-older-adults/
- https://agsjournals.onlinelibrary.wiley.com/doi/10.1111/jgs.70600
米国における65歳以上の成人における、時間とともに変化する体格指数（BMI）、ウエスト周囲径と全死因死亡率との関連 Time-Varying Body Mass Index, Waist Circumference and All-Cause Mortality in US Adults Aged 65 or Older
Furong Xu, Jacob E. Earp, Bryan J Blissmer, Julie Coiro, Steven A. Cohen, Geoffrey W. Greene
Journal of the American Geriatrics Society Published: 19 August 2026
DOI:https://doi.org/10.1111/jgs.70600
ABSTRACT
Background
This study examined associations of body mass index (BMI) category and waist circumference (WC) independently and in tandem on all-cause mortality risk among US adults aged ≥ 65 years.
Methods
The present study utilized 14 years of longitudinal data (2011–2024) from 6905 participants in the National Health and Aging Trends Study. Cox proportional hazards models were used to estimate the hazard ratios (HRs), adjusted for baseline age, race, education, annual income, smoking status, and homebound status.
Results
Compared with normal weight, overweight males (HR, 0.54 [95% CI, 0.45–0.66]) and males with class I and II obesity (HR, 0.49 [95% CI, 0.37–0.65]) had lower mortality risk. High WC was associated with greater mortality risk in males (HR, 1.24 [95% CI, 1.07–1.44]). Similar patterns were observed in females. In joint BMI-WC analyses, overweight regardless of WC status and class I and II obesity with high WC were associated with lower mortality risk among males. Being underweight, regardless of WC status, and having normal weight with high WC were both associated with higher mortality risk in both sexes.
Conclusions
These findings highlight the adverse association of central adiposity and the limitations of BMI-only classification for mortality risk stratification in older adults.
Summary
- Key points○Higher body mass index (BMI) is associated with lower mortality risk in older adults, whereas higher waist circumference is associated with higher mortality risk independent of BMI.
○Few nationally representative US studies in adults aged ≥ 65 years have evaluated the joint association of BMI category and abdominal obesity (waist circumference) with mortality using time-updated (time-varying) measures.
- Why does this paper matter?○The obesity epidemic is a major public health concern in U.S. adults aged 65 or older.
○Our findings provide epidemiological evidence consistent with recent recommendations to incorporate measures of central adiposity (e.g., waist circumference) alongside BMI when evaluating health risk in older adults.
