Published on: April 12, 2013
by Endocrine Today:
Patients with diabetes are at risk for early-onset dementia and mortality, especially among older age groups, according to researchers in Australia. Although the epidemiology surrounding the association between diabetes and dementia remains fairly uncertain, researchers wrote that the effect of diabetes on dementia projections based on their study is likely to worsen, given the incidence and prevalence of type 2 diabetes and obesity.
Research fellow Renate R. Zilkens, MPH, of Curtin University, and colleagues conducted a retrospective population study utilizing Western Australian hospital inpatient, mental health outpatient and death records to compare the age at index dementia record (proxy for onset age) and survival outcomes among dementia patients with and without pre-existing diabetes (n=25,006; diabetes, 17.3%).
According to the researchers, dementia onset occurred at an average of 2.2 years earlier and death 2.6 years earlier in patients with diabetes compared with patients without diabetes (P<.0001). Additionally, the age-specific mortality rates increased in patients with diabetes, they wrote.
“The public health significance of a 2.2-year age difference seems modest, yet it has been estimated that an intervention able to delay the onset of Alzheimer’s disease by 2 years would reduce the projected quadrupling of Alzheimer’s disease prevalence by year 2050 by over 20%,” the researchers wrote.
Upon further analyses, the death rate was increased with a long duration of diabetes, particularly in early-onset dementia. However, in dementia diagnosed before age 65 years, patients with at least a 15-year history of diabetes died nearly twice as fast vs. those without diabetes (HR=1.9; 95% CI, 1.3-2.9), according to data.
Moreover, these death rates were significantly higher when associated with a long duration of diabetes in the 65- to 74-year-old age group (HR=1.5; 95% CI, 1.1-1.19) and 75- to 84-year-old age group (HR=1.4; 95% CI, 1.2-1.6).
“These findings, amplified in early-onset dementia and by long-duration diabetes, have major implications for estimating the future dementia disease burden due to diabetes as well as clinical implications for affected patients and their families,” Zilkens and colleagues wrote.
Disclosure: The researchers report no relevant financial disclosures.
Perspective by Tamara L. Wexler, MD, PhD:
One issue that arises when we talk about diabetes and dementia is what kind of dementia it was; was it really Alzheimer’s disease or was it misclassified? The researchers of this paper were very careful to say how they got the diagnosis and that it was not certain. It was very responsible in that nature.
Not that surprisingly, it does add validation to studies which have previously reported earlier onset dementia due to diabetes. It may well still be that that’s more vascular which also makes sense given what we know about how diabetes affects the vasculature. There has been a lot in the news recently and it’s been reported for a long time that there may be some association and the brain is essentially one of the end-organs impacted by diabetes.
If there are high levels of blood sugar that aren’t controlled, what often happens is that impacts the vasculature or the brain as it does other areas of the body. I think it was just sort of an indication of the potential negative quality that diabetes may in fact have for early-onset dementia.
But still, the paper suggested an interesting association in a well-done, large scale study.
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