Researchers from the Department of Metabolism & Endocrinology, Tokyo, Japan have recently observed that olfactory dysfunction precedes the development of probable dementia in older patients with type 2 diabetes.
The study is published in the Diabetes Research and Clinical Practice.
Patients with type 2 diabetes are generally reported to have olfactory dysfunction. While the underlying mechanism of olfactory dysfunction in patients with type 2 diabetes remains unclear, hyperglycemia and insulin resistance may be involved in the development of olfactory dysfunction.
Thus, even though we have previously demonstrated an association between olfactory dysfunction and cognitive impairment in older patients with type 2 diabetes, it remains largely unknown whether olfactory dysfunction could be an early marker of future cognitive impairment in patients with type 2 diabetes.
Therefore, Haruna Sanke and colleagues carried out the present study with the aim to investigate whether olfactory dysfunction could be an early marker of future dementia in older patients with type 2 diabetes.
This exploratory study included 151 older Japanese outpatients with type 2 diabetes who did not have a diagnosis of probable dementia at baseline. A multivariate logistic regression model was used to determine whether Open Essence (OE) test score at baseline is associated with the development of probable dementia.
The results showed that-
Over 3 years, approximately 9% of the study subjects developed probable dementia.
Subjects with olfactory dysfunction at baseline developed probable dementia more frequently than those without.
Multivariate logistic regression showed that lower OE test score, higher age, lower Mini-Mental State Examination (MMSE) score, higher total protein concentration, and more frequent use of a sulfonylurea are significantly associated with the development of probable dementia.
Stepwise multivariate regression analysis demonstrated that change in OE test score over 3 years is significantly associated with change in MMSE score.
Hence, the authors concluded that "olfactory dysfunction precedes the development of probable dementia in older patients with type 2 diabetes."