Premature immune aging in obesity: a testable framework linking immunosenescence, metaflammation, and multiorgan dysfunction.

Obesity is a chronic immunometabolic disorder associated with alterations in biological aging pathways and increased risks of type 2 diabetes mellitus, cardiovascular disease, metabolic dysfunction-associated steatotic liver disease, chronic kidney disease, neurodegeneration, and cancer. Obesity and chronological aging share several characteristics, including low-grade inflammation, cellular senescence, mitochondrial dysfunction, oxidative stress, epigenetic alterations, and immune remodeling. However, these similarities do not necessarily establish accelerated biological immune aging. This review critically evaluates obesity-associated immunosenescence, metaflammation, and multiorgan dysfunction by examining supporting and conflicting findings, alternative explanations, methodological limitations, and therapeutic evidence. Although experimental and observational studies report alterations in lymphocyte differentiation, innate immune function, inflammatory signaling, and selected biological-age markers, these findings are not uniformly observed across immune-cell populations, tissues, or metabolic phenotypes. Metabolically healthy obesity, tissue-dependent epigenetic aging, and differences between human and animal findings challenge the interpretation of obesity as a universal accelerator of immunosenescence. Furthermore, chronological age, cytomegalovirus infection, sex-related differences, adiposity distribution, and metabolic comorbidities complicate attributing immune alterations specifically to obesity. The proposed immunosenescence-metaflammation-multiorgan dysfunction framework therefore remains a testable mechanistic hypothesis rather than an established causal pathway. Although immune-cell phenotypes, epigenetic clocks, inflammatory mediators, and multi-omics signatures may help characterize obesity-associated immune dysfunction, their specificity, longitudinal validity, and clinical utility remain insufficiently established. Nutritional interventions, exercise, bariatric surgery, and pharmacological treatments can improve selected metabolic and inflammatory outcomes, but these improvements do not necessarily demonstrate sustained reversal of biological immune aging. By critically comparing supportive evidence with contradictory observations and unresolved causal relationships, this review identifies the principal limitations of current mechanistic, biomarker, and therapeutic research. Future studies should prioritize longitudinal immune profiling, direct functional assessment, tissue- and sex-specific analyses, causal validation, and controlled interventions incorporating validated immune-aging endpoints to determine whether premature immune aging is a measurable and therapeutically modifiable consequence of obesity.