Older Americans today seem to have significantly less risk of memory loss and dementia than a decade ago, according to a new study published online February 20 in Alzheimer’s & Dementia.

Researchers at the University of Michigan and the Ann Arbor VA Health System led by Dr. Kenneth Langa, MD, PhD, associate professor of medicine at the UM studied cognitive impairment among people aged 70 and older in the United States not living in nursing homes or other institution. Some 7,400 people took memory tests in 1993 and about 7,100 other people took the same tests in 2002 for the study.

The researchers were surprised to find that 8.7 percent of participants age 70 and older had cognitive impairment (from significant memory loss to full-blown Alzheimer’s disease) compared to 12.2 percent in 1993.

“What we found is that the risk for someone who has 70 and older in 1993 of having impaired cognition was higher than the risk for someone in that same age group in 2002,”  Langa said in the study.

The research does not show why serious memory loss was less likely among the later generation, but Langa said that better education higher economic status and better care for cognitive impairment risk factors such as high blood pressure, high cholesterol, and smoking might help the trend.

The researchers discovered that the proportion of adults 65 and older with high-school diploma increased from 53 percent in 1990 to 72 percent in 2003, while the proportion of those with a college degree increased from 11 percent to 17 percent during the same period.

“From these results, we can say that brain health among older Americans seems to have improved in the decade studied, and that education and wealth may be a big piece of the puzzle. What we may be seeing here is the accumulated effects of better education and better cardiovascular prevention,” Langa said in the study.

Overall, the results appear to be optimistic, the authors conclude. However, the situation may aggravate because the current epidemic of type 2 diabetes, obesity and high blood pressure. Moreover, the number of Americans who will get dementia likely will increase as the number of older Americans climbs. About 80 million baby boomers will reach age 70 in the next 8 or 10 years.

“There’s going to be a large increase in the number of people with Alzheimer’s disease and dementia, even with a decreased [individual] risk. We might lose what we’ve gained,” Langa said.

Langa noted that further studies were needed on cognitive impairment among people in nursing homes.

More than 5 million Americans are estimated to be living with Alzheimer’s, the most common form of dementia, a progressive and ultimately fatal disease that damages and kills areas of the brain. According to the Centers for Disease Control and Prevention, more than 65,000 Americans died of Alzheimer’s in 2004.