For years, doctors have been saying that keeping your cholesterol levels in check as you age is good for your brain as well as your heart, but a new study suggests the connection between cholesterol and dementia later in life isn't quite so clear-cut. After more than 1,400 Swedish women followed for 32 years, Johns Hopkins researchers found that those with high cholesterol at mid-life were at no greater risk of developing Alzheimer's and other types of dementia than women with lower levels. In addition, the women whose cholesterol levels decreased the most from middle to older age were 2.5 times more likely to develop dementia than those whose levels increased or stayed the same.
Both cell and animal studies have suggested that high cholesterol contributes to Alzheimer's disease, the researchers noted, but they stressed that the relationship between cholesterol and dementia may vary over a lifetime. "Our findings highlight how risk factors can change over the course of a person's life span," said Michelle M. Mielke, an assistant professor of psychiatry at Hopkins and lead author of the study, which was published online Nov. 10 in the journal Neurology. "My biggest worry is that people will look at these results and decide that cholesterol doesn't matter, but that's not what we're saying," Mielke added.
"We know that high cholesterol is a very strong risk factor for cardiovascular disease and still needs to be treated with diet, exercise and possibly medication." Mielke added that it was unclear why a decline in cholesterol levels in old age was linked to a higher risk of dementia, but said it might be an early part of the disease process. "As people start to develop symptoms, they often forget to eat and start losing weight, and that may be why their cholesterol goes down." For the study, Mielke and her colleagues examined data from the Prospective Population Study of Women, which began in 1968 and consisted of 1,462 Swedish women between the ages of 38 and 60.