Metabolic disorders linked to cognitive decline

Moral of the story: Manage your chronic diseases! Stay on top of treatment, exercise and see your doctor. The last thing you want on top of diabetes is Alzheimer's disease.

Metabolic disorders linked to cognitive decline
March 17, 2009 Allison Gandey
Edited from Medscape Medical News—a professional news service of WebMD

New York, NY and Seattle, WA - Evidence is mounting that metabolic and neurological diseases share common risk factors, according to two studies in the March 2009 issue of the Archives of Neurology.
"Preventing heart disease, stroke, and diabetes—or making sure these conditions are well managed in patients diagnosed with them—can potentially slow the disease progression of Alzheimer's," senior author on one of the studies, Dr Yaakov Stern (Columbia University, New York), said in a news release. Stern et al, led by Dr Elizabeth Helzner (Columbia University) hypothesized that vascular factors such as heart disease, stroke, diabetes, hypertension, smoking, and blood lipid levels may predict the progression of Alzheimer's disease [1]. The group studied 156 patients followed for a mean of 3.5 years. Participants were from the Washington Heights and Inwood Columbia Aging Project, a multiethnic, community-based, prospective study of aging in northern Manhattan.
Researchers found that patients with a history of diabetes and elevated levels of cholesterol, especially LDL cholesterol, had faster cognitive decline. In fact, each 10-U increase in cholesterol and LDL cholesterol was associated with a 0.10-standard-deviation decrease in cognitive score per year of follow-up (p<0.001 for total cholesterol; p=0.001 for LDL cholesterol).
Investigators found that a history of heart disease and stroke were associated with cognitive decline only in carriers of the APOE e4 allele.
"These findings indicate that controlling vascular conditions may be one way to delay the course of Alzheimer's, which would be a major development in the treatment of this devastating disease," Stern said.Fluctuations in weight may boost dementia risk
In the second study published in the same issue of the Archives of Neurology, investigators show that obese middle-aged adults and underweight elderly people have an increased dementia risk [2].
Using data from the Cardiovascular Health Study, researchers studied the body-mass index (BMI) of participants at mid- and late life. Patients were from a community-dwelling sample at four US sites.
Investigators included 2798 people. Of these, 480 had incident dementia, 245 had Alzheimer's disease, and 213 had vascular dementia.
They found that middle-aged patients who were obese had an increased risk for dementia (BMI >30 vs normal-weight BMI 20 to 25), adjusted for demographics (hazard ratio 1.39; 95% CI 1.03-1.87), although this observation was weakened after adjustment for cardiovascular risk factors (hazard ratio 1.36; 95% CI 0.94-1.95).
These results help explain the 'obesity paradox.'
But the risk estimates were reversed in assessments of late-life BMI. Underweight people, those with a BMI of less than 20, had an increased risk for dementia (hazard ratio 1.62; 95% CI 1.02-2.64). Surprisingly, being overweight later in life was not associated with an increased risk (hazard ratio 0.92; 95% CI 0.72-1.18), and being obese reduced the risk for dementia (hazard ratio 0.63; 95% CI 0.44-0.91).
"These results help explain the 'obesity paradox,' " the researchers, led by Dr Annette Fitzpatrick (University of Washington, Seattle), write. "Differences in dementia risk across time are consistent with physical changes in the trajectory toward disability."
These findings suggest that the predictive ability of BMI changes across time, they note
"Weight loss occurs with comorbidities at older ages and is often reflective of poor health," write Fitzpatrick and her team. "Weight loss, along with psychological, behavioral, and mobility problems, is one of the principal manifestations of Alzheimer's disease. Weight loss may predate dementia onset by as much as 10 years."
The researchers conclude: "These results reinforce the necessity of monitoring weight loss closely in older adults."
The complete contents of Medscape Medical News, a professional news service of WebMD, can be found at www.medscape.com, a website for medical professionals.
Sources
Helzner EP, Luchsinger JA, Scarmeas N, et al. Contribution of vascular risk factors to the progression in Alzheimer disease. Arch Neurol 2009; 66:343-348.
Fitzpatrick AL, Kuller LH, Lopez OL, Midlife and late-life obesity and the risk of dementia: cardiovascular health study. Arch Neurol 2009; 66:336-342.
Related links
Adherence to Mediterranean diet reduces risk of major chronic diseases [Prevention > Prevention; Sep 12, 2008]
Heart disease linked to poor cognitive function in middle age [Brain/Kidney/Peripheral > Brain/Kidney/Peripheral; Jul 23, 2008]
Low HDL-C associated with poor memory [HeartWire > Brain/Kidney/Peripheral; Jun 30, 2008]
High cholesterol linked to increased AD risk [HeartWire > Medscape Medical News; Nov 06, 2006]
Low cholesterol linked to reduced cognitive function [HeartWire > News; Mar 23, 2005]
Lipid metabolism abnormalities observed in brain aging and Alzheimer's disease [HeartWire > News; Feb 15, 2004]