Association between health-related quality of life and medication discrepancies: a cross-sectional study of older Chinese adults with type 2 diabetes mellitus.

With the rapid aging of the global population, dementia is recognized as one of the most significant global challenges for healthcare and social care systems in the twenty-first century. Cognitive impairment, often serving as a key precursor to dementia onset, represents a transitional stage between normal aging and dementia. In China, the overall prevalence of cognitive impairment in 2018 was 15.5%, representing 38.77 million affected individuals. Given these alarming trends, it is crucial to identify and mitigate risk factors for cognitive impairment at an early stage in order to reduce the occurrence of dementia. Over the past 30 years, the prevalence of obesity has increased significantly worldwide and has become a major public health concern. Studies have demonstrated a significant association between obesity, as measured by various indices, and cognitive impairment. However, with the extensive investigation of body composition, traditional obesity indicators such as body mass index (BMI) have limitations in accurately reflecting fat distribution, because fat distribution and body composition vary dramatically among individuals with the same BMI. To better embody fat distribution, the body roundness index (BRI), coined by Thomas et al. as a novel anthropometric measurement, additionally considers waist circumference and can more comprehensively estimate body fat percentage and visceral adipose tissue. BRI was found to be superior to other anthropometric indicators in estimating the risk for various chronic diseases such as cardiometabolic disease, cancer, as well as premature death. The relationship between the BRI and cognitive impairment has garnered increasing research interest in recent years; however, the evidence remains inconsistent. Some cross-sectional or retrospective studies have supported a significant negative association between elevated BRI and cognitive function, particularly in older adults and individuals with type 2 diabetes, with some indicating a stronger effect in women. In contrast, other studies from rural China and Iran found no significant association or a non-linear, inverted U-shaped relationship. In addition, a US population study reported that BRI was negatively correlated with the cognitive function score but was not significantly associated with cognitive impairment. These discrepancies may be attributed to variations in study populations, cognitive assessment tools, and study designs, which further complicate the interpretation of existing findings. Meanwhile, few studies have explored the association between BRI and cognitive decline in a cohort with long-term follow-up. Thus, further well-designed, prospective studies are needed to clarify the role of BRI in cognitive function. The pathways linking visceral adiposity to cognitive impairment are complex, with evidence pointing to the roles of systemic inflammation and metabolic dysregulation. Compared to chronological age, biological age could provide a more accurate reflection of an individual’s true aging status and susceptibility to age-related diseases. Studies have documented that accelerated biological aging plays a critical role in the progression of cognitive decline and neurodegenerative diseases. Furthermore, the alterations and accumulation of metabolites in individuals with obesity may significantly accelerate aging. Despite these insights, the exact role of routine clinical biomarker-based biological aging in the interrelationship between BRI and both cognitive decline and impairment has yet to be fully elucidated.