Higher HbA1c levels are associated with an increased risk for dementia in adults with type 2 diabetes, according to study findings presented at the 51st European Association for the Study of Diabetes Annual Meeting.
“It is well known that diabetes and dementia have become public health challenges worldwide,” Aidin Rawshani, MD, of Sahlgrenska University Hospital, and a PhD student at the National Diabetes Register of Sweden and department of clinical and molecular medicine at Gothenburg University, said during a presentation. “Studies have shown that individuals with type 2 diabetes have an increased risk of developing dementia by roughly 50%. Studies have also shown that [glycemic control] is related to risk of dementia, but there are gaps in knowledge here, and we set out to disentangle these associations.”
Rawshani and colleagues analyzed data from 353,214 adults aged 50 years or older (mean age, 62 years) with type 2 diabetes and no known hospitalization for dementia from the Swedish National Diabetes Registry between 2003 and 2012, and merged those data with data from the Swedish national inpatient and outpatient databases and national cause of death registry. Researchers followed the cohort until hospital admission for dementia, death or the end of the study period. Researchers used Cox regression to analyze the link between patients’ HbA1c level and incident dementia, using time-fixed covariates to examine HbA1c and time-updated covariates to examine other predictors of dementia.
During a mean follow-up of 4.8 years, 13,159 adults were admitted to the hospital with either a primary or secondary diagnosis of dementia (3,499 adults with Alzheimer’s disease). Within the cohort, adults with an HbA1c of 10.5% or higher were 50% more likely to be diagnosed with dementia when compared with adults with an HbA1c of 6.5% or less (HR = 2.36, 95% CI, 2-2.78).
“Individuals with type 2 diabetes and very high blood sugar levels are at increased risk of developing dementia, according to our association study,” Rawshani told Endocrine Today. “This means that we can modify the risk of developing dementia in individuals with type 2 diabetes by optimizing [HbA1c] levels.” The risk for developing dementia also increases dramatically as age increases, according to Rawshani.
Stroke was a contributing factor in dementia risk, the researchers noted. Adults with a history of previous stroke were 40% more likely to develop dementia than those without stroke (HR = 7.69; 95% CI, 7.22-8.18). Albuminuria was also associated with an increased risk for dementia, according to researchers.
Patients who developed dementia had a 40% survival rate after 10 years of follow-up vs. a 70% survival rate for patients who did not develop dementia, Rawshani said.
“We’re only in the beginning of understanding the relationship between metabolic disorders and [their] impact on cognitive disease,” Rawshani said. “We have several ongoing projects to study both dementia and the gradual decline in cognitive functions in individuals with type 2 diabetes and also type 1 diabetes.” by Regina Schaffer
Rawshani A, et al. Abstract #10. Presented at: 51st EASD Annual Meeting; Sept. 14-18, 2015; Stockholm.
Disclosure: Rawshani reports no relevant financial disclosures.