People who rate their health as poor or fair appear to be significantly more likely to develop dementia later in life, according to a study published in the October 5, 2011, online issue of Neurology®, the medical journal of the American Academy of Neurology.

"Having people rate their own health may be a simple tool for doctors to determine a person's risk of dementia, especially for people with no symptoms or memory problems," said study author Christophe Tzourio, M.D., Ph.D., director of the Inserm unit 708 Neuroepidemiology at the University of Bordeaux 2 in France.

Other studies have shown that people who rate their own health as poor are more likely to die or develop a disease, especially vascular disease such as heart attack or stroke, than people who rate their health as good. The results hold true even after researchers account for other health conditions, such as hypertension or elevated cholesterol.

At the start of the study, 8,169 people age 65 years or older were asked to rate their health and were followed for nearly seven years. During the study, 618 people developed dementia.

The risk of dementia was 70 percent higher in people who rated their health as poor and 34 percent higher in people who rated their health as fair compared to those who rated their health as good.

In addition, the study found that the association between people's health ratings and developing dementia was even stronger for those who did not have any memory problems or other issues with thinking skills. Among those with no cognitive problems, those who rated their health as poor were nearly twice as likely to develop dementia as those who rated their health as good.

"We know that having a large social network and social activities are associated with a decreased risk of dementia," said Tzourio. "Therefore, it's possible that rating one's health as poor might be associated with behaviors that limit social interaction and in turn accelerate the dementia process."

The study was supported by the French National Institute of Health and Medical Research, the Victor Segalen Bordeaux II University, Sanofi-Aventis and the Foundation for Medical Research in France.