In adults with diabetes, increasing variability in fasting plasma glucose and HbA1c may be associated with increased risk for Alzheimer’s disease, researchers from China report.
Cheng-Chieh Lin, MD, PhD, of the department of medical research and department of family medicine at China Medical University Hospital, and colleagues evaluated data from the National Diabetes Care Management Program on 16,706 adults aged at least 60 years (55.2% men) with type 2 diabetes without Alzheimer’s disease to determine whether FPG and HbA1c variability, as represented by the coefficient of variation, have a significant and independent association with Alzheimer’s disease. Follow-up was a median of 8.98 years.
FPG coefficient of variation and HbA1c coefficient of variation were estimated from outpatient visits within the first year of the index date. Participants were divided into groups based on tertiles of FPG variability ( 17.4%, first; 17.4%-34.6%, second; > 34.6%, third) and HbA1c variability ( 8.3%, first; 8.3%-16.3%, second; > 16.3%, third).
Overall, 831 cases of Alzheimer’s disease were identified for a crude incidence rate of 6.22 per 1,000 person-years. Incidence rates of Alzheimer’s disease increased with increasing tertiles of FPG variability (first, 5.2 per 1,000; second, 5.83 per 1,000; third, 7.69 per 1,000) and increasing tertiles of HbA1c variability (first, 5.25 per 1,000; second, 5.95 per 1,000; third, 7.5 per 1,000).
Compared with participants without Alzheimer’s disease, those with Alzheimer’s disease were older, had a longer diabetes disease duration, and they were more likely to be women, nonsmokers, living a low-income household and veterans. They were more likely to use insulin or insulin plus oral hypoglycemic medication, were less likely to have obesity and were more likely to have a history of coronary artery disease, congestive heart failure, stroke, hypertension, atrial fibrillation, chronic obstructive pulmonary disease or hypoglycemia.
“We report that visit-to-visit glycemic variability, determined by FPG [coefficient of variation] and HbA1c [coefficient of variation], is independently associated with [Alzheimer’s disease], in addition to FPG, HbA1c and other traditional risk factors, in patients with [type 2 diabetes],” the researchers wrote. “Our findings indicate the existence of a shared pathophysiological link between glycemic variability and [Alzheimer’s disease]. We suggest that cognitive functions should be routinely screened in patients with [type 2 diabetes], especially for those with notable glycemic variability. Further research is required to elucidate the linkage mechanisms, which could also lead to clarification of the pathogenesis of [Alzheimer’s disease], and to confirm whether FPG [coefficient of variation] or HbA1c [coefficient of variation] is a valuable therapeutic target for at-risk patients.” – by Amber Cox
: The authors report no relevant financial disclosures.