Duration and degree of hyperglycemia related to dementia risk: Study

Results suggest that diabetes management in the early stage can lower the risk of developing dementia.

South Korea: A recent study in the journal Diabetes Care has discovered an association between the risk of Alzheimer's disease and the duration and degree of hyperglycemia. The researchers suggest intervention during the prodromal stage of chronic disease (e.g., prediabetes) for preventing dementia.

Previous studies have indicated that diabetes increases dementia risk by producing dementia-causing substances in the body or by chronically affecting the blood supply to the brain. However, studies on the relationship between diabetes complications, prediabetes, and dementia were relatively scarce, and their relationship was unclear. To clarify the same, Woo Jung Kim, Yonsei University College of Medicine, Yongin, Republic of Korea, and colleagues aimed to investigate the risk of incident dementia according to fasting glucose levels and presence of comorbidities. 

The researchers selected 8,400,950 subjects aged ≥40 years who underwent health examinations in 2009–2010 using a health insurance claims database and the results of biennial health examinations in South Korea. They were followed until 2016. Their baseline characteristics were categorized by presence of diabetes (yes/no) and glycemic status as normoglycemia, impaired fasting glucose (IFG), new-onset diabetes, or known diabetes (duration <5 years or ≥5 years). Adjusted hazard ratios (aHRs) were estimated for dementia occurrence in each category. 

During the observation period of 48,323,729 person-years, all-cause dementia developed in 353,392 subjects (4.2%). 

 "These results suggest that if patients manage their diabetes in the early stage, they can lower the risk of developing dementia. However, eventually, if the duration of diabetes prolongs, the risk of dementia inevitably increases," Professor Kim said. "To prevent dementia, it is crucial to prevent diabetes through sufficient exercise and proper diet control." 

"Mild degrees of hyperglycemia and presence of comorbidities were associated with incident dementia," wrote the authors. "Intervention during the prodromal stage of a chronic disease (e.g., prediabetes) could be considered for dementia prevention."

Reference:

Risk of Incident Dementia According to Glycemic Status and Comorbidities of Hyperglycemia: A Nationwide Population-Based Cohort Study

Woo Jung Kim, Seo Jung Lee, Eun Lee, Eun Young Lee, Kyungdo Han

Diabetes Care Oct 2022, dc210957; DOI: 10.2337/dc21-0957