Mental activity may help prevent dementia

Participating in mentally challenging leisure activities such as reading and playing board games may help elderly people stay mentally sharp. Researchers found that people aged 75 years or more who engaged in leisure activities had a lower risk of dementia than other elderly people. It is unclear whether increased participation in leisure activities lowers the risk of dementia or whether participation in such activities declines during the preclinical phase of dementia (New England Journal of Medicine 2003;348:2508-16). But not all activities seem to be equally effective in reducing the risk of dementia. People who reported often playing board games, reading, playing a musical instrument or doing crossword puzzles were less likely to develop dementia than people who said they engaged in those activities only rarely. However, writing and taking part in group discussions seemed to offer no protection against memory-robbing conditions such as Alzheimer's disease. The researchers followed a cohort of 469 people aged over 75 who lived in the community and did not have dementia at the start of the study. They measured how often the people took part in leisure activities, deriving a cognitive activity score and a physical activity score for each person. These were composite measures that took account of all of the cognitive or physical activity of each person. Researchers adjusted the scores for age, sex, level of education, presence or absence of chronic medical illnesses, and baseline cognitive status. The participants were followed for up to 21 years. More than half the participants were followed for at least five years. Over a median follow up period of 5.1 years dementia developed in 124 people (Alzheimer's disease in 61 people, vascular dementia in 30, mixed dementia in 25, and other types of dementia in eight). Among the leisure activities reading, playing board games, playing musical instruments, and dancing were associated with a lower risk of dementia. An increase of one point in the cognitive activity score was significantly associated with a lower risk of dementia (hazard ratio 0.93 (95% confidence interval 0.90 to 0.97), but there was no association between a one point increase in the physical activity score and risk of dementia. The study's lead author, Dr Joe Verghese, of the Albert Einstein College of Medicine in New York, said that cognitive activity may stave off dementia by increasing a person's "cognitive reserve." For instance, mental exercise may increase the connections between brain cells or promote new networks between cells, he said. So, while people who engage in these activities may get dementia as often as other people, mentally active people can perhaps afford to lose more brain cells before the symptoms appear. Researchers have shown that people who develop dementia tend to halt their activities as a result. Consequently experts have debated whether people who do less mental exercise and later develop dementia are inclined to abandon their activities because they had an early, undetected form of the disease. To address this concern the researchers excluded people who developed dementia in the first seven years of the study, as they might have had an early form of the disease when the study began. In an accompanying editorial Dr Joseph Coyle, of Harvard Medical School in Boston, agreed that promoting leisure activities among elderly people couldn't do any harm and might help. While researchers continue to investigate the relative contributions of genes and the environment to dementia, "seniors should be encouraged to read, play board games, and go ballroom dancing, because these activities, at the very least, enhance their quality of life, and they just might do more than that," he writes.