Age-related cognitive decline may be less common now then it once was, according to new research. In a nationally representative survey of older Americans, the results of which were published in Alzheimer's & Dementia, researchers from the University of Michigan found that the rate of cognitive impairments, like memory and language problems, declined slightly over the past decade.
The researchers tested the mental functioning of more than 14,000 people over the age of 69. Half of the subjects were surveyed in 1993 and the other half were surveyed in 2002. Of those surveyed in 1993, 12.2% had cognitive impairments, while while only 8.7% of those surveyed in 2002 had developed the same problems. When applied to the general population, this relatively small gap represents about 900,000 fewer people with cognitive impairments in 2002 than in 1993.
A number of factors may explain the decline in cognitive impairments among older Americans, and the researchers suggest that a large part of the decline could stem from wealth and education level. Compared to their counterparts of the early 1990s, current older Americans tend to be more educated and wealthier, with the average household net worth (in 2001 dollars) for adults over the age of 65 rising from $108,000 in 1989 to $180,000 in 2001. The researchers determined that education level and wealth could account for roughly 40% of the difference between the two groups. Specifically, wealth offers access to better health care, and better overall health may signify better cognitive health as well. Since the 1990s, advancements in medications used to treat cardiovascular and cerebrovascular diseases may have contributed to decreasing rates of cognitive impairments by reducing the risk for heart attack, stroke, and vascular dementia.
Education may also help keep the brain healthy by increasing an individual's likelihood of engaging in mentally stimulating work and leisure activities throughout their lifetime. However, the study's results also indicate the complex nature of cognitive health among older individuals. While the study found that fewer people had cognitive impairments in 2002 than in 1993, those who did develop these problems had a greater chance of dying than those surveyed in 1993. The reason may lie again with education, as this trend was more pronounced among the more educated subjects. These results support a theory raised by previous research. Although education may seem to protect against Alzheimer's, it may actually delay symptoms of the disease by allowing the brain to function normally for a longer period of time, and this results in a rapid decline once symptoms finally appear.
This study indicates that the overall rate of age-related cognitive impairments may declining slightly, but by studying these trends, researchers may be even better able to treat or prevent cognitive difficulties. As the baby boomers reach old age and the high rate of obesity continues to place many at risk for cardiovascular disease, cognitive decline will remain a problem. The current trend indicates how important educational, medical, and social factors can be to the cognitive health of older individuals, and with continued research, we can help aging adults retain their mental clarity as long as possible.
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