Biobehavioral and Interpersonal Predictors of Cognitive Impairment in Older Adults With Type 2 Diabetes: A Systematic Review of Cohort Studies.

The type 2 diabetes-cognitive decline link is a potent independent risk factor for cognitive impairment and dementia. However, preventive strategies often neglect diabetes-specific risks, and reviews generally rely on cross-sectional data. This systematic review of observational cohort studies was conducted to synthesize longitudinal evidence on the multidimensional predictors of cognitive impairment in older adults with type 2 diabetes. PubMed, CINAHL, PsycINFO, and Cochrane Library were searched. Included studies followed older adults with type 2 diabetes for at least six months and evaluated biological, behavioral, psychological, or interpersonal predictors of cognitive impairment. Data were narratively synthesized and study quality was assessed using the Newcastle-Ottawa Scale. Forty-three studies met the inclusion criteria. Biological predictors were the most extensively studied (n = 31). Nine studies addressed behavioral factors, two examined social and environmental predictors, and no studies investigated psychological factors. Higher HbA1c levels, glucose variability, severe hypoglycemia, vascular complications, and inflammatory/metabolic markers significantly predicted higher cognitive impairment risk. Poor diet, low physical activity, and sleep disorders were associated with cognitive decline. Social determinants of health and limited social contact were linked to higher dementia risk, although evidence remains sparse. This review highlights the critical need to prioritize modifiable predictors, especially diabetes-specific biological markers and health behaviors, to prevent or delay cognitive impairment in older adults with type 2 diabetes. Future research should focus on developing individualized, multidimensional preventive interventions that incorporate behavioral and contextual factors. Additionally, validated multifactorial risk prediction models are needed to identify high-risk populations and inform tailored care.