A study of 11,000 people in the U.S. has found a significant decline in the levels of cognitive impairment between 1993 and 2002. The prevalence of cognitive impairment went down from 12.2% in 1993 to 8.7% in 2002. The researchers attributed this decline to increased rates of college education, greater personal wealth and better treatment for cardiovascular problems. In recent years research has suggested that the more education a person receives early in life the more his or her brain will be able to stay sharp later. During the time of the study the number of older people with a high-school diploma rose from 53% to 72% and the number of people with a college education rose from 11% to 17%. At the same time the use of cholesterol-lowering drugs and blood-pressure medication increased dramatically during the 1990s. This may have had the effect of reducing the incidence of vascular dementia - cognitive problems brought on by mini-strokes, strokes and decreased blood flow to and within the brain due to hardened or clogged arteries.
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