This article is more than 5 years old. Information may no longer be current.
Elevated 2-hour postload glucose, longer diabetes duration risk factors for brain atrophy
Older Japanese adults with longstanding type 2 diabetes and higher 2-hour postload glucose levels had lower global brain and hippocampal volume vs. adults without diabetes or with late-life diabetes, according to recent study findings.
“These associations remained unchanged after adjustment for potential confounding
factors and after the exclusion of subjects with dementia,” Naoki Hirabayashi, MD, of the department of environmental medicine at the Graduate School of Medical Sciences at Kyushu University in Fukuoka, Japan, and colleagues wrote. “Thus, diabetes is a possible risk factor for hippocampal atrophy, which precedes the onset of dementia among subjects with diabetes.”
Hirabayashi and colleagues analyzed data from 1,238 adults aged at least 65 years (540 men) participating in the Hisayama study, an ongoing study initiated in 1961. Since 1985, participants have undergone comprehensive screening surveys of cognitive function and activities of daily living every 6 to 7 years; this cohort underwent MRI brain scans and a comprehensive health examination in 2012. Researchers measured total brain volume (TBV), intracranial volume (ICV) and hippocampal volume (HV), and they examined the associations between diabetes-related parameters and the ratios of TBV to ICV (an indicator of global brain atrophy), HV to ICV (an indicator of hippocampal atrophy) and HV to TBV (an indicator of hippocampal atrophy beyond global brain atrophy) after adjustment for age and sex.
Within the cohort, 286 (23%) had diabetes, with 83 newly diagnosed.
When compared with patients without diabetes, researchers found that participants with diabetes had lower mean values of TBV to ICV (77.6% vs. 78.2%; P < .001), HV to ICV (0.513% vs. 0.529%; P < .001) and HV to TBV (0.66% vs. 0.676%; P = .002) after adjustment. Participants with elevated, 2-hour postload glucose levels (at least 11.1 mmol/L) saw decreased ratios for all three parameters vs. those with a 2-hour postload glucose level of less than 7.8 mmol/L, as did those with a longer duration of diabetes, particularly those with a diabetes duration of at least 17 years.
“Intriguingly, our findings showed that the subjects with diabetes had significantly lower mean HV-to-TBV ratio values, indicating not that hippocampal atrophy simply reflects global brain atrophy in subjects with diabetes but, rather, that the hippocampus is predominantly affected by diabetes,” the researchers wrote. “In addition, in our subjects, a longer duration and a midlife onset of diabetes were significantly associated with a lower HV, possibly suggesting that a long exposure of diabetes particularly worsens hippocampal atrophy. Our findings highlight the importance of the prevention and early management of diabetes toward reducing the risk of global brain and hippocampal atrophy and subsequent dementia in late life.” – by Regina Schaffer
Disclosure: This study was funded in part by a research grant from AstraZeneca.