ST. PAUL, Minn. – Contrary to earlier research, a new, long-term study suggests that cholesterol level in mid-life may not be linked to later development of Alzheimer's disease, according to a study published in the November 10, 2010, online issue of Neurology®, the medical journal of the American Academy of Neurology. However, the results suggest that large decreases in cholesterol levels in old age could be a better predictor of developing the memory-robbing disease.
"While some studies suggest that cholesterol is a risk factor for dementia, others have not replicated this finding, so the possible association has been under debate," said study author Michelle M. Mielke, PhD, with Johns Hopkins University School of Medicine in Baltimore.
For the study, 1,462 dementia-free Swedish women between the ages of 38 and 60 were followed for 32 years. As part of the study, the women were given a physical exam, heart tests, chest x-rays and blood tests. The group was also surveyed for smoking habits, alcohol and medication use, education and medical history. Throughout the study, body mass index (BMI), a measurement of weight-per-height, and blood pressure were taken. At four points, the women were tested for dementia.
After 32 years, 161 women had developed dementia.
The study found that cholesterol measured in middle or old age showed no link to dementia, which is contrary to some earlier studies. However, the study also found that the women whose cholesterol levels decreased the most from middle to older age were more than twice as likely to develop dementia as those whose cholesterol levels increased or stayed the same. The risk increased from 8.9 percent for those who maintained or had increased cholesterol over the course of the study to 17.5 percent for people with the greatest decline in cholesterol.
Mielke said that decreased cholesterol levels greater than what is expected in old age might be a more accurate indicator of dementia risk then cholesterol levels in middle age. In addition, despite the finding that cholesterol did not influence dementia risk, Mielke recommends that people still follow heart healthy guidelines. "Cholesterol should still be monitored and treated through diet, exercise and medication for cardiovascular and overall health."
The study was supported by the National Institutes of Health, the National Institute on Aging, the National Institute of Neurological Disorders and Stroke, the Swedish Research Council, the Swedish Brain Power Project, the University of Gothenburg, Swedish Council for Working Life and Social Research, Swedish Alzheimer Association, European Commission Seventh Framework Program, Svenssons Foundation, the Swedish Society of Medicine, the Söderström-Königska Nursing Home Foundation, the Foundation för Gamla Tjänarinnor, Hjalmar Svenssons Foundation, The Swedish Society of Medicine, the Göteborg Medical Society, the Lions Foundation, the Dr. Felix Neubergh Foundation, the Wilhelm and Martina Lundgren Foundation, the Elsa and Eivind Kison Sylvan Foundation, and the Alzheimer's Association Zenith Award.
The American Academy of Neurology, an association of more than 22,000 neurologists and neuroscience professionals, is dedicated to promoting the highest quality patient-centered neurologic care. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as epilepsy, dystonia, migraine, Huntington's disease, and dementia.
For more information about the American Academy of Neurology, visit http://www.aan.com.