The American baby boomer generation is not as cognitively sharp during middle age and later in life as previous generations, according to a study published online this week in the Journals of Gerontology: Social Sciences.
The findings are “clear and alarming,” say the study’s authors, for they suggest that recent declines in the incidence of dementia in the United States may soon begin to reverse. Cognitive decline can be an early warning sign of dementia.
“With the aging population in the United States, we were already likely to see an increase in the number of people with dementia,” says Hui Zheng, the study’s lead author and a sociologist at Ohio State University, in a released statement. “But this study suggests it may be worse than we expected for decades to come.”
For the study, Zheng and his colleagues analyzed data collected from 30,191 men and women, aged 51 and older, who participated in the University of Michigan’s Health and Retirement Study from 1996 through 2014. Every two years, the participants filled out surveys. They also completed a battery of cognitive tests in which they were asked to perform such mental tasks as recalling words they had heard previously, counting backwards from 100 by sevens, identifying objects depicted in drawings, and naming the president and vice president.
The scores from these tests were compared with those from tests taken by people over the age of 50 in past generations. The analysis revealed a steady improvement in scores from the “greatest generation” (born 1890-1923) through the “early children of depression” generation (1924-1930) and the “late children of depression” generation (1931-1941). The scores peaked with the “war babies” generation (1942-1947). After that they began to decline, starting with the early baby boomers (born 1948-1952) and decreasing further with the mid baby boomers (1954-1959).
To make sure that the results were not skewed by a higher number of older people (who tend to have poorer cognition) among the baby boomer test takers, the researchers compared the scores within age groups across all generations. Baby boomers still had, on average, the lowest scores.
“Baby boomers already start having lower cognition scores than earlier generations at age 50 to 54,” says Zheng.
Not enough late baby boomers (1960-1964) were in the study to include them in the analysis, but Zheng says he believes they will fare no better than their generation’s earlier waves.
The decline in the baby boomers’ cognitive scores occurred among both genders and all racial and ethnic groups. In addition, the drop was found among boomers in all education, occupation and income groups.
At first glance, this widespread decline in cognitive function is puzzling. Baby boomers tend to have had healthier childhoods than people of past generations, and, on average, they come from more advantaged family backgrounds (more educated parents with higher socioeconomic status, for example). They also tend to have more years of education and are more likely to have worked in a white-collar job.
As Zheng notes, however, “the decline in cognitive functioning that we’re seeing does not come from poorer childhood conditions.” He and his co-authors point to a long list of other factors associated with the baby boomer generation that may explain their poorer cognitive functioning. These include lower household wealth, lower likelihood of marriage, and higher levels of loneliness, depression and psychiatric problems. A significant percentage of baby boomers also have cardiovascular risk factors linked to cognitive problems, such as obesity, physical inactivity, high blood pressure, type 2 diabetes and stroke.
Yet, as the researchers underscore in their paper, depression and other psychiatric problems explain more of the cognitive decline among baby boomers than all other diseases combined.
“If it weren’t for their better childhood health, more favorable likelihood of having a white-collar occupation, baby boomers would have even worse cognitive functioning,” Zheng adds.
Limitations and implications
This study comes with caveats. Most notably, the study uses test scores to measure cognitive function rather than clinical assessments. In addition, the survey data included limited childhood information, especially measures of nutrition and illness, which may have an impact on cognitive functioning later in life. Furthermore, substance abuse — particularly opioid abuse — has become an important cause of early death among baby boomers. That substance abuse may also be contributing to the worsening cognitive functioning observed in this study.
“Despite these limitations, this paper portrays a clear and alarming cohort pattern in cognitive functioning, which is different from the overall favorable pattern in dementia over time found in prior studies,” Zheng and his co-authors write.
“This decline may potentially reverse past favorable trends in dementia as Baby Boomers reach older ages and cognitive impairment becomes more common if no effective interventions and policy responses are in place,” they add. “Measures, such as increasing financial support, promoting social relationships, encouraging physical activities, and treating psychiatric and cardiovascular diseases, may well pay off in slowing or even preventing the potential increase in dementia in the decades to come.”
FMI: You’ll find the study on the website for the Journals of Gerontology: Social Sciences.