A recent study found that patients younger than the onset of diabetes had a significant association with a higher risk of subsequent dementia.
Researchers led by Dr. Archana Singh-Manoux of EpiAgeing at the Université de Paris found that for every occurrence of diabetes five years earlier, there was a significant association with a higher risk of dementia.
The team evaluated the data in the ongoing cohort study of Whitehall II, a collection of 10,308 employees in London government departments that was set up between 1985 and 1988. Follow-up examinations take place every 4 to 5 years, with 2015–2016 being the most recent completed data and 2020–2021 still being collected.
Investigators have also linked the data to the UK’s National Health Service (NHS). The records are updated annually until March 2019.
study
The study comprised 7 clinical assessments between 1985 and 2016 in which venous blood samples were taken either in the morning after a fasting period of ≥ 8 hours or after a fasting period of ≥ 5 hours after a light, fat-free breakfast. Fasting glucose was measured by the glucose oxidase method.
Data on self-reported, doctor-diagnosed type 2 diabetes and prescriptions for diabetes medication were collected at each visit. The national database of hospital episode statistics (HES) has been linked to track participants.
The researchers defined type 2 diabetes using fasting glucose (126 mg / dL) measurements during clinical examination, drug use, doctor-diagnosed diabetes, or the record of diabetes in the HES database from 1985 to 2019.
The team’s secondary exposures included the Finnish Diabetes Risk Score (FINDRISC), fasting glucose, and prediabetes.
Dementia cases were assessed by March 2019 by linking them to three registers including the HES, the mental health services dataset and the Office of National Statistics death register.
Results
639 patients (6.3%) were diagnosed with dementia during the study period. Investigators said they had more chronic illnesses during the follow-up period and had a worse cardiovascular risk profile by the age of 60.
At the follow-up examination, 1,710 participants (16.9%) developed diabetes and 153 (8.9%) of these participants were subsequently diagnosed with dementia.
At the age of 55, the dementia rate per 1000 person-years was 3.14 for participants without diabetes and 5.06 for participants with diabetes with a hazard ratio (HR) of 2.14 (95% CI, 1.44-3.17) .
At the age of 70, the dementia rate for participants without diabetes was 8.85 per 1000 person-years and for participants with diabetes was 13.88 per 1000 person-years with a HR of 1.58 (95% CI, 1.22-2.03).
Cases of diabetes in patients ≥ 70 years of age comprised 48.3% of the cases. Investigators treated diabetes and covariates as time-varying measures. The dementia rates were 1.76 per 1000 person-years for participants without diabetes and 6.25 for participants with diabetes with a HR of 1.40 (95% CI, 1.15-1.70).
The data for the occurrence of diabetes from 0 to 5 years earlier had a significant association with subsequent dementia with an HR of 1.53 (95% CI, 1.03-2.29) and a dementia rate of 8.63 per 1000 person-years .
Diabetes that occurred 6 to 10 years earlier had a dementia rate of 10.51 per 1000 person-years.
Researchers looked at diabetes status at the age of 70, when the HR of patients with diabetes that occurred more than 10 years earlier was 2.12 (95% CI, 1.50-3.00), with a dementia rate of 18 , 30 per 1000 person-years.
The diabetes that occurred 6-10 years earlier had a HR of 1.49 (95% CI, 0.95-2.32) with a dementia rate of 12.99 per 1000 person-years.
The diabetes onset rate 0-5 years earlier had a HR of 1.11 (95% CI, 0.70-1.76) with a dementia rate of 10.00 per 1000 person-years.
In the analysis adjusted for socio-demographic and health factors, the team found that at the age of 70, every 5 years younger age at the onset of type 2 diabetes was associated with a dementia HR of 1.24 (95% CI, 1.06-1.46). .
The team found little association between dementia and FINDRISC or preclinical diabetes in participants without diabetes, regardless of age.
Conclusion
The researchers concluded that younger age at the onset of diabetes has a significant association with higher HR from dementia.
“Taken together, these results underscore the importance of early diabetes age and cardiovascular comorbidity in people with diabetes on the risk of dementia,” the researchers wrote.
The team did not determine the exact mechanism behind the club. They suggested that this could be due to links between brain metabolic disorders and insulin resistance, as well as higher rates of hypoglycaemia in the treatment of diabetes, which increases the risk of dementia.
“Additionally, studies don’t always show a consistent association between diabetes and Alzheimer’s disease features such as amyloid and tau pathology,” the researchers wrote. “Although the histopathological, molecular, and biochemical abnormalities in Alzheimer’s disease are well characterized, there is no unified framework that links these features together.”
The study “Relationship between age at onset of diabetes and subsequent risk of dementia” was published online in JAMA.
