Since the mid-1990s, rates of dementia cases in the United States has steadily risen, according to new research published in Epidemiology.
The research, conducted by the Max Planck Institute for Demographic Research (MPIDR), scoured through the data of over 30,000 participants as part of the Health and Retirement Study (HRS). The age group of the participants were 50 and over.
“Accumulating evidence suggests risk of cognitive impairment is declining in high-income countries. Much of this research uses longitudinal surveys in which learning over repeated tests may bias results,” the co-authors implied in their article.
“We analyze trends in cognitive impairment in the United States, accounting for prior test experience and selective mortality.”
Initiated over the time span of 1996-2014, the results indicated that the models not accounting for test experience point to a decrease of cognitive impairment and dementia over time. But when controlling for test experience, the opposite was the case.
“In our primary models, prevalence of any cognitive impairment increased for women from 18.7% to 21.2% (annual change 0.7%, 95% confidence interval [CI], 0.1%, 1.3%) and for men from 17.6% to 21.0% (annual change 1.0%, CI, 0.5%, 1.4%),” the findings showed.
“For dementia, women’s annual increase was 1.7% (CI, 0.8%, 2.6%) and men’s 2.0% (CI, 1.0%, 2.9%).”
Higher educational attainment inhibited a larger increase in cognitive impairment over time.
“Risk of cognitive impairment increased from 1996 to 2014. Uncovering determinants of increasing cognitive impairment risk should become a research priority,” researchers suggested in their findings.
