Whole-blood NAD⁺ and frailty in community-dwelling older adults: cross-sectional findings
In a cross-sectional analysis of 529 community-dwelling adults aged 65 or older, lower whole-blood NAD⁺ concentration was associated with frailty; the association weakened after adjustment for hematocrit. This is an association, not evidence of cause. [1]
Automatic summary · not editorially reviewed
The key findings
Among 529 community-dwelling adults aged 65 or older, 32 (6.0%) had frailty, assessed with the revised Japanese Cardiovascular Health Study Criteria. [1]
Median whole-blood NAD⁺ was lower in participants with frailty than in those without (24.00 vs. 25.00 µmol/L; P = 0.007). [1]
After adjustment for age, sex and fasting time, higher whole-blood NAD⁺ was associated with lower odds of frailty (odds ratio per 1 µmol/L, 0.871; 95% CI, 0.780–0.970), but the association was attenuated after additional adjustment for hematocrit (odds ratio, 0.911; 95% CI, 0.800–1.034). [1]
The source at a glance
- Study type / format
- Cross-sectional analysis
- Population / context
- Community-dwelling adults aged 65 or older in the 2025 Itabashi Longitudinal Study on Aging (529 participants; 54.3% women).
- Summary based on
- Study abstract
- Original publication
- September 16, 2026
Frailty and NAD⁺ in 529 older Itabashi participants
The study asked whether whole-blood NAD⁺ concentration is linked to frailty in community-dwelling adults aged 65 or older. It used cross-sectional data from the 2025 Itabashi Longitudinal Study on Aging. Among 529 participants, 54.3% were women and 32 (6.0%) had frailty, assessed with the revised Japanese Cardiovascular Health Study Criteria. Median whole-blood NAD⁺ was lower in participants with frailty than in those without (24.00 vs. 25.00 µmol/L; P = 0.007).
Supporting source [1]
Adjusted odds and hematocrit sensitivity analysis
After adjustment for age, sex and fasting time, higher whole-blood NAD⁺ concentration was associated with lower odds of frailty (odds ratio per 1 µmol/L increase, 0.871; 95% confidence interval, 0.780–0.970; P = 0.013). A spline analysis showed no clear evidence of a nonlinear relationship. The association persisted with broader adjustment using Firth regression (odds ratio, 0.880; 95% confidence interval, 0.782–0.986) but was attenuated after additional adjustment for hematocrit (odds ratio, 0.911; 95% confidence interval, 0.800–1.034). The authors suggest blood cell composition may partly explain the association.
Supporting source [1]
Cross-sectional design limits causal interpretation
This was a cross-sectional analysis, so NAD⁺ and frailty were measured at the same time and the direction of any relationship cannot be established. The authors call for further studies using cell- and tissue-specific measurements to clarify the relationship between NAD⁺ metabolism and frailty. The abstract does not report follow-up or whether the full text was reviewed.
Supporting source [1]
How to interpret this
Abstract only; the full text was not reviewed. This is a cross-sectional analysis, so it cannot show whether NAD⁺ changes precede frailty or vice versa. Frailty was present in 32 of 529 participants, and the association weakened after hematocrit adjustment.
Based on the study abstract; the full paper, tables and supplementary data were not reviewed.
Source & supporting passages
Shida T, Hatanaka S, Kojima N, Osuka Y, Sasai H. · europepmc.org · September 16, 2026