In recent decades, diabetes mellitus (DM) has become a significant contributor to chronic disease morbidity. According to the International Diabetes Federation data of 2021, approximately 537 million adults worldwide are affected by this disease (Sun et al., 2022). DM can affect the function of various organ systems, particularly the cerebrovascular structures and neural tissues, which can lead to a range of structural and functional disorders within the nervous system. Abnormalities in glucose metabolism, such as fasting and postprandial hyperglycemia, as well as prediabetic states and full-blown diabetes, can contribute to neural dysfunction and the development of acute and chronic nervous system disorders, including cognitive decline (Amidei et al., 2021). Moreover, extensive research has provided solid evidence of the impact of diabetes on cognitive function. Both pathological and physiological perspectives have proposed mechanisms to elucidate how diabetes, as a metabolic syndrome, contributes to cognitive impairment. Diabetes-related impaired glucose utilization can lead to alterations in brain energy metabolism and disrupt brain function (Xue et al., 2019; Harris et al., 2012; Jimenez-Blasco et al., 2020). Moreover, diabetes can also result in structural changes in the brain (Launer et al., 2011; Erus et al., 2015; Cherbuin et al., 2012; Chen et al., 2014; Biessels and Reijmer, 2014).

Cardiovascular diseases (CVDs) are significant chronic noncommunicable diseases with a global impact. Despite a decline in age-standardized CVD death rates over the latter half of the 20th century, they continue to be the leading cause of morbidity and mortality worldwide, including in the United States (US) (Piepoli et al., 2016; Lloyd-Jones et al., 2010). The burden of CVD remains substantial, resulting in a decreased quality of life, loss of life years, and significant direct and indirect medical costs (Lloyd-Jones et al., 2010). Approximately 50 % of adults in the US are affected by some form of CVD (Angell et al., 2020). Over the past two decades, multiple studies have presented evidence supporting the potential impairment of cognitive function associated with CVDs (Muller et al., 2007; Stanek et al., 2009; Weiner et al., 2011; Haring et al., 2013; Weinstein et al., 2018; Smolderen et al., 2022; Nowak et al., 2023).

Diabetes and CVD often lead to cognitive impairment, with CVD being recognized as the primary cause of mortality in individuals with diabetes. Therefore, assessing the impact of these diseases on cognitive function as well as determining whether there is an interaction between them is crucial. In the presence of an interaction, patients with both conditions may require more comprehensive strategies for preventing and treating cognitive decline. Simultaneous consideration of treatment for both diseases is necessary for achieving a greater impact. Conversely, in the absence of an interaction, targeted interventions can be implemented to protect cognitive functioning in patients experiencing the cooccurrence of these conditions. This approach can enable patients to allocate their time, energy, and finances efficiently, leading to optimal treatment outcomes. Thus, this study aimed to evaluate cognitive function impairment resulting from diabetes and CVD while also investigating any potential interaction between these conditions.