Older adults with type 1 diabetes with prolonged exposure to HbA1c at least 8% are at least twice as likely to develop dementia over 6 years vs. similar adults with only 10% of measurements in the same range, according to findings published in Diabetes Care.
“Prior work has established type 1 diabetes as a risk factor for dementia,” Mary E. Lacy, PhD, a postdoctoral researcher in the department of epidemiology and biostatistics at the University of California, San Francisco, and colleagues wrote in the study background. “However, the relationship between glycemic control and subsequent risk of dementia in those with type 1 diabetes remains unclear.”
Lacy and colleagues analyzed electronic medical records from 3,433 adults aged at least 50 years with type 1 diabetes and no prevalent dementia at baseline from the Kaiser Permanente Northern California Diabetes
Registry, a registry of all members with diabetes using a combination of pharmacy and laboratory information, hospitalization records and outpatient diagnoses.
Cohort entry date was defined as the first date between 1996 and Sept. 30, 2015, that a patient was aged at least 50 years and had a type 1 diabetes diagnosis (mean baseline age, 56 years; 80.1% white; 47.1% women).
Dementia diagnoses were identified based on EMRs, and HbA1c measurements were obtained from the Kaiser laboratory database (mean number of measurements per patient, 13.5). Patients were stratified by HbA1c level into the following categories: less than 6%; 6% to 6.9%; 7% to 7.9%; 8% to 8.9%; and at least 9%. Researchers used Cox proportional hazard models to estimate the association between categories of cumulative exposure to HbA1c and risk for dementia, with age used as the time scale.
During a mean follow-up of 6.3 years, 155 adults (4.5%) were diagnosed with dementia, with a mean age at diagnosis of 64 years.
Researchers found that dementia risk was higher for adults exposed to an HbA1c of at least 8% vs. those exposed to an HbA1c between 6% and 7.9%.
Those exposed to an HbA1c between 8% and 8.9% for at least 75% of measurements were 2.51 times more likely to develop dementia during follow-up vs. those with less than 10% of measurements in that range (95% CI, 1.23-5.11).
Those exposed to an HbA1c of at least 9% for 75% of measurements were 2.13 times more likely to develop dementia during follow-up vs. those with less than 10% of measurements in the same range (95% CI, 1.13-4.01).
Conversely, adults with prolonged exposure to an HbA1c between 6% and 6.9% were 58% less likely to develop dementia during follow-up vs. those with only 10% of measurements in the same range (adjusted HR = 0.42; 95% CI, 0.21-0.83), whereas those with prolonged exposure to an HbA1c between 7% and 7.9% were 61% less likely to develop dementia vs. those with less than 10% of measurements in the same range (aHR = 0.39; 95% CI, 0.18-0.83).
The researchers noted that they did not have data on cognitive performance measures and were unable to assess glycemic control and changes in cognition or investigate possible reverse effects of cognitive decline on glycemic control.
“A clinical diagnosis of dementia is likely preceded by a period of cognitive decline during which one’s ability to properly manage glycemia may be impacted; this is an especially important limitation in this population of older adults with type 1 diabetes where self-care plays such an important role in disease management,” the researchers wrote.
Disclosures: The authors report no relevant financial disclosures.
HbA1c 6% i artikeln DCCT = 42 mmol/mol
HbA1c 7% i artikeln DCCT = 53
HbA1c 8%i artikeln DCCT = 64 mmol/mol
HbA1c 9% DCCT = 75
hbA1c 10% DCCT = 86
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Long-term Glycemic Control and Dementia Risk in Type 1 Diabetes
Mary E. Lacy, Paola Gilsanz, Andrew J. Karter, Charles P. Quesenberry, Mark J. Pletcher and Rachel A. Whitmer
Diabetes Care 2018 Aug; dc180073.
Individuals with type 1 diabetes have experienced an increase in life expectancy; yet, it is unknown what level of glycemic control is ideal for maintaining late-life brain health. We investigated the association of long-term glycemic control with dementia in older individuals with type 1 diabetes.
RESEARCH DESIGN AND METHODS We followed 3,433 members of a health care system with type 1 diabetes, ages ≥50 years, from 1996 to 2015. Repeated measurements of hemoglobin A1c (HbA1c), dementia diagnoses, and comorbidities were ascertained from health records. Cox proportional hazards models were fit to evaluate the association of time-varying glycemic exposure with dementia, with adjustment for age, sex, race/ethnicity, baseline health conditions, and frequency of HbA1c measurement.
RESULTS Over a mean follow-up of 6.3 years, 155 individuals (4.5%) were diagnosed with dementia. Patients with ≥50% of HbA1c measurements at 8–8.9% (64–74 mmol/mol) and ≥9% (≥75 mmol/mol) had 65% and 79% higher risk of dementia, respectively, compared with those with <50% of measurements exposed (HbA1c 8–8.9% adjusted hazard ratio [aHR] 1.65 [95% CI 1.06, 2.57] and HbA1c ≥9% aHR 1.79 [95% CI 1.11, 2.90]). By contrast, patients with ≥50% of HbA1c measurements at 6–6.9% (42–52 mmol/mol) and 7–7.9% (53–63 mmol/mol) had a 45% lower risk of dementia (HbA1c 6–6.9% aHR 0.55 [95% CI 0.34, 0.88] and HbA1c 7–7.9% aHR 0.55 [95% CI 0.37, 0.82]).
CONCLUSIONS Among older patients with type 1 diabetes, those with majority exposure to HbA1c 8–8.9% and ≥9% had increased dementia risk, while those with majority exposure to HbA1c 6–6.9% and 7–7.9% had reduced risk. Currently recommended glycemic targets for older patients with type 1 diabetes are consistent with healthy brain aging.