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TOPLINE
A German population-based study found that higher body mass, fat mass, visceral fat, and liver fat were associated with lower estimated glomerular filtration rate (eGFR) values, especially in women and adults older than 40 years. In contrast, higher relative fat-free mass was associated with higher eGFR values.
METHODOLOGY
- Researchers analysed data from a German population-based cohort study to examine sex- and age-specific associations between body composition markers and eGFR values.
- They included 4211 adults aged 20-79 years, of whom MRI-based assessment of visceral and subcutaneous fat was performed in 1941 participants, and liver fat content was measured in 1890 participants.
- Body composition was assessed through anthropometric measurements (BMI and waist-to-hip ratio); bioelectrical impedance analysis (fat mass index, fat-free mass index, body cell mass index, and relative fat-free mass); and MRI-based quantification of subcutaneous, visceral, and liver fat mass.
- The eGFR was calculated using both creatinine- and cystatin C-based equations, including Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 2009 and 2012 equations and European Kidney Function Consortium (EKFC) 2021, 2023, and 2026 equations.
TAKEAWAY
- Higher values of BMI, body surface area, waist circumference, fat mass index, fat-free mass index, and body cell mass index were all associated with lower eGFR values across all equations; higher visceral and liver fat content were also linked to lower eGFR values in almost all equations, whereas subcutaneous fat was only associated with lower eGFR values in cystatin C-based and combined equations.
- Higher relative fat-free mass (%) was associated with higher eGFR values (beta-coefficient per SD increase, 0.78 for the EKFC equation and 1.47 for the CKD-EPI equation).
- In women, increased body or fat mass was associated with lower eGFR values across almost every equation, with effect sizes mostly larger than those in men; this sex-based difference was more pronounced with CKD-EPI equations than with EKFC equations.
- Among participants younger than 40 years, higher body or fat mass was associated with higher eGFR values. Among those aged 40 years or older, the association reversed, showing that higher body or fat mass was linked to lower eGFR values. Higher relative fat-free mass was negatively associated with eGFR values in younger age groups but positively associated in older individuals.
IN PRACTICE
"Overall, with the exception of FFM% [relative fat-free mass], higher values of body composition markers were associated with a higher eGFR in younger age groups but with a lower eGFR in older ones. In general, effect sizes were stronger in women," the authors of the study wrote.
"The [study] results highlight the importance of body composition, sex and age for the glomerular filtration rate," they added.
SOURCE
This study was led by Marlene Agnes Günther, University Medicine Greifswald, Greifswald, Germany. It was published online on August 07, 2026, in Clinical Kidney Journal.
LIMITATIONS
The GFR was estimated rather than directly measured using an exogenous filtration marker, which may have introduced inaccuracy, particularly at higher values. The eGFR values frequently fell into a range affected by estimation inaccuracies for high values (> 60 mL/min/1.73 m2). Additionally, selection bias may have occurred as healthier and more mobile individuals were more likely to participate.
DISCLOSURES
The SHIP cohort study received subsidies from the Ministry of Culture and Social Affairs of the State of Mecklenburg-Vorpommern. This study did not receive any specific funding. The authors declared having no conflicts of interest.
This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.
