Dementia risk for patients suffering from cognitive impairment has increased over the past 20 years, according to a new article published in Epidemiology

Most studies in recent years have presented evidence that the risk of cognitive impairment is declining in most developed countries. Many of these previous studies employ a test that the same participants take repeatedly. This results in the participants learning the test and, if not taken into account, can lead to biased results, according to the current study. 

Researchers at the Max Planck Institute for Demographic Research (MPIDR) examined data from more than 32,000 participants from the Health and Retirement Study (HRS) to analyze cognitive impairment between 1996 to 2014. The HRS is a nationally representative study of US residents over the age of 50 and includes the Telephone Interview for Cognitive Status, which is designed to detect decline of cognitive abilities. 

With their model, the prevalence of cognitive impartment increased in both men and women. The increase was especially pronounced in people with lower levels of education, over the age of 85, and Latinas, according to the study. Some of the increase may be attributed to people living longer with dementia. 

"Results based on models that do not control for test experience suggest that risk of cognitive impairment and dementia decreases over the study period. However, when we controlled for testing experience in our model the trend reverses," Mikko Myrskylä, director at the MPIDR in Rostock, Germany, said in a press release. 

Reference:

Elderly in the US: Risk of dementia has been rising for years - instead of falling (Press release) Germany, August 27, 2020, ScienceDaily, accessed, August 31, 2020