At least half of all cases of Alzheimer's disease can be linked to seven major risk factors, and controlling them could sharply reduce the risk of developing the devastating disease, according to researchers from UC San Francisco and the San Francsco VA Medical Center. Leading the list worldwide is lack of education -- specifically not finishing high school -- while living the life of a couch potato is the biggest risk factor in the United States, according to the study presented Tuesday at a Paris meeting of the International Conference on Alzheimer's Disease and published online in the journal Lancet Neurology. Modifying the risk factors in the population could put a sizable dent in Alzheimer's incidence, according to the study's lead author, psychiatrist Deborah Barnes of the VA.
Alzheimer's disease, which is characterized by a loss of brain function, an inability to care for one's self and, eventually, death, is a growing problem as the population ages. Worldwide, about 35 million people are thought to suffer from the disease, including nearly 6 million cases in the United States. As the population grows older still, the worldwide total is predicted to triple by the year 2050.
Barnes and her colleagues studied a wide variety of reviews and meta-analyses and then used a sophisticated mathematical program to calculate the risk associated with various factors. They concluded that, worldwide, lack of education contributed 19% of the risk, 14% came from smoking, 13% from lack of physical activity, 10% from depression, 5% from high blood pressure at midlife, 2% from diabetes and 2% from obesity.