Association of Phenotypic Age Acceleration With Pancreatic Fat Percentage in a UK Biobank Imaging Population

ABSTRACT Background Excessive pancreatic fat is associated with metabolic disorders. Phenotypic age acceleration, derived from routine clinical biomarkers, reflects multisystem physiological deviation beyond chronological age. This study examined whether phenotypic ageing is associated with pancreatic fat percentage in a UK population. Methods This study included 23 558 UK Biobank participants who attended the initial assessment and the first imaging visit. Phenotypic age acceleration was defined as the residual from regressing phenotypic age on chronological age, both obtained at the initial assessment. A positive acceleration value means that an individual is biologically older than their chronological age. Pancreatic fat was quantified as the proton density fat fraction (PDFF) derived from abdominal MRI. Generalised linear models with a gamma distribution and log link were constructed to estimate the association between phenotypic age acceleration and pancreatic PDFF. Subgroup and sensitivity analyses were performed. Results A total of 8559 (36.3%) people were identified as biologically older. Each 1‐year increase in phenotypic age acceleration was associated with a 2% (mean ratio = 1.02, 95% CI: 1.02, 1.03) higher mean pancreatic PDFF in multivariable‐adjusted models. People in the highest quartile of phenotypic age acceleration had a 37% (mean ratio = 1.37, 95% CI: 1.33, 1.40) higher mean pancreatic PDFF than those in the lowest quartile. Subgroup analyses showed broadly consistent associations. Interactions were observed for sex and non‐fasting triglycerides, but results were comparable. Sensitivity analyses showed consistent results. Conclusions Phenotypic age acceleration was associated with higher mean pancreatic fat percentage in a large UK Biobank imaging population. Longitudinal studies with repeated imaging assessments are required to determine temporality and clinical relevance.