Seasonal BMI Amplitude and Risk of Kidney Function Decline in Japanese Adults With Type 2 Diabetes (JDDM 82)
Authors' conclusion
In type 2 diabetes, larger intra-annual BMI fluctuations were independently and dose-dependently associated with kidney function decline. Seasonal BMI amplitude may identify higher-risk individuals; whether reducing seasonal BMI fluctuations improves kidney outcomes warrants prospective evaluation.
Study context
- Population
- Japanese outpatients with T2D, nationwide multicenter cohort (2014–2020)779 reached primary end point
- Participants
- 6,700 outpatients
- Exposure
- Seasonal BMI fluctuation
- Outcome
- ≥40% decline in eGFR
- Follow-up
- Median 6.8 years
Methodological detailsnationwide, multicenter, multivariable Cox models with clinic as random effect, Monthly BMI modeled with seasonal-trend LOESS to quantify within-year peak-to-trough difference, Results robust across sensitivity analyses, incl. time-varying medication exposure
- Nationwide
- Multicenter
- Multivariable Cox models with clinic as random effect
- Monthly BMI modeled with seasonal-trend LOESS to quantify within-year peak-to-trough difference
- Results robust across sensitivity analyses, incl. time-varying medication exposure
Main finding
As reported in the abstract
≥40% eGFR decline
Hazard ratio (95% CI)
Per 1-SD increase in BMI fluctuation
1.23(1.16–1.31)
Highest tertilevs Lowest tertile
1.72(1.42–2.09)
Observational data: associations, not effects.
Secondary outcomes
≥30% estimated glomerular filtration rate (eGFR) decline
- HR (pattern consistent with primary)
- HR 1.18, 95% CI 1.13-1.23
Creatinine doubling
- HR (pattern consistent with primary)
- HR 1.30, 95% CI 1.17-1.45
Incident chronic kidney disease (CKD) stage ≥3
- HR (pattern consistent with primary)
- HR 1.11, 95% CI 1.07-1.16
Longitudinal eGFR decline
- Steeper eGFR decline in the highest-fluctuation group
Sensitivity analyses
- Results robust across sensitivity analyses, incl. time-varying medication exposure models
Parts of this Brief are withheld: the automatic checks could not confirm them against the abstract.
Original publication
Seasonal BMI Amplitude and Risk of Kidney Function Decline in Japanese Adults With Type 2 Diabetes (JDDM 82). Diabetes Care. Published 14 April 2026. doi:10.
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