Researchers from the University of California, Los Angeles have been looking into the links between socio-economic status and cognitive decline in older people. They studied 6,476 adults born before 1924. The participants were tested five times between 1993 and 2002 on various memory and cognition tests. There was a link between higher socio-economic status and better education and higher scores on the initial test but as time went on the rate of decline was similar across all demographic groups. People who were older at the start of the study, whose partner had died or who had never married declined more quickly over the course of the study.
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