Metabolic and Neurological Disorders May Share Common Risk Factors

Metabolic disorders such as obesity and diabetes appear to share risk factors with and may influence the development of Alzheimer’s disease and other forms of dementia, according to several reports published in the March issue of Archives of Neurology, one of the JAMA/Archives journals.

The issue—a theme issue on neurological disorders related to metabolic diseases—is being published in conjunction with a JAMA theme issue on diabetes, obesity and their comorbidities. The March issue of Archives of Ophthalmology, along with the April issues of Archives of Pediatrics & Adolescent Medicine, Archives of Dermatology and Archives of Surgery, will also feature research on this theme.

Studies featured in this issue include the following:

Women With More Components of Metabolic Syndrome More Likely to Develop Cognitive Impairment

Women with the cluster of cardiovascular risk factors known collectively as the metabolic syndrome appear likely to develop cognitive impairment over a four-year period. Kristine Yaffe, M.D., of the University of California, San Francisco, and the San Francisco Veterans’ Affairs Medical Center, and colleagues assessed 4,895 older women (average age 66.2) who did not have cognitive impairment at the beginning of the study.

Of the 497 (10.2 percent) women who had the metabolic syndrome 7.2 percent (36) developed cognitive impairment during a four-year period, compared with 4.1 percent (181 of 4,398) of those who did not have the metabolic syndrome. Each additional component of the syndrome—such as abdominal obesity, high blood pressure and low HDL cholesterol levels—was associated with a 23 percent increase in risk of cognitive impairment.

“As the obesity and sedentary lifestyle epidemic escalates throughout the world, identification of the role of these modifiable behaviors in increasing risk for development of deleterious outcomes, such as cognitive impairment, is critical,” the authors conclude. “Future research should assess whether identification of cognitive impairment among patients with the metabolic syndrome or more aggressive clinical control of the factors that compose the metabolic syndrome might lessen the risk of developing cognitive impairment in elderly people.”
(Arch Neurol. 2009;66[3]:324-328.)

Obesity Associated With Worsening Cognitive Function in Older Men

Older men with higher levels of fat appear more likely to experience declines in cognitive function over seven years, but the same association does not appear to occur in older women. Alka M. Kanaya, M.D., of the University of California–San Francisco, and colleagues studied 3,054 elderly individuals enrolled in the Health ABC Study.

Participants’ adiposity (fat level) was assessed by body mass index, waist circumference, sagittal diameter (distance between the back and the highest point of the abdomen), total fat mass and subcutaneous (beneath the skin) and visceral fat (fat between the internal organs) measured by computed tomography. Men whose measurements were higher were more likely to experience declines in scores on a cognitive functioning test administered at the beginning of the study and again after three, five and eight years. However, no association was observed in women.