Working 9 to 5 May Protect Women From Memory Loss

Pauline Anderson

July 17, 2019

Elizabeth Rose
Mayeda, PhD

LOS ANGELES — Working women experience a slower rate of age-related memory loss than their nonworking counterparts, new research shows.  

Results of a large longitudinal study show that memory decline later in life occurred twice as quickly women who did not work in mid-life compared with those who did.

"Our findings provide evidence that participation in the paid labor force may help prevent later life memory decline for women," lead author Elizabeth Rose Mayeda, PhD, assistant professor of epidemiology, Fielding School of Public Health, University of California at Los Angeles (UCLA), told Medscape Medical News.

Clinicians may want to consider the social experiences of their patients, including how they spend their time, said Mayeda. "It's important to remember that work is a major life factor that shapes people's experiences throughout life."

The findings do not explain why working women have slower memory decline, but mental stimulation and the social and financial benefits associated with work may play a role, said Mayeda.

The study was presented on July 16 here at the Alzheimer's Association International Conference (AAIC) 2019.

Women Disproportionately Affected

Understanding factors that influence the risk of Alzheimer's disease (AD) in females is important as women account for about two thirds of those living with AD and other dementia types, said Mayeda.

Although a lot of research related to women and AD focuses on sex as a biological variable, Mayeda's new study looked at gender and the social experience of women.

"The role of women in the workforce and family demands have changed dramatically over the last century," she noted.

For the study, investigators used data from 6385 women born between 1935 and 1956 who participated in the Health and Retirement Study, a nationally representative longitudinal study of US residents over age 50 years.

The mean age of participants at study enrollment was 55.2 years. The mean follow-up was 13.8 years.

Women in the study reported whether they worked for pay, were married, and had children under age 18 years at home.

Researchers grouped women into five work-family patterns: working nonmothers, working married mothers, working single mothers, nonworking single mothers, and nonworking married mothers.

The largest group was working married mothers (n = 4450).

Researchers used standardized tests to measure memory (immediate and delayed word list recall) about every 2 years between 1995 and 2016, when women were middle-aged or older.

Mayeda noted that memory decline "is considered a hallmark of Alzheimer's disease dementia."

Intriguing Finding

Researchers adjusted the analyses for factors that might influence work-family patterns and later life memory decline, including age, race/ethnicity, birth region, childhood socioeconomic status (SES), and educational attainment.

Results showed no major group differences in memory function when the women were in their late 50s and even at age 60. However, after age 60, the groups started to separate.

The rate of memory decline was most rapid in nonworking women and slowest for working women regardless of whether they had children.

The investigators note that compared with working married mothers, nonworking single mothers declined 0.26 — and nonworking married mothers declined 0.29 — more standardized units on the memory score — from ages 65 to 75 years.

"Memory decline for women who did not engage in the paid labor force was a little over twice as fast compared to women who did," said Mayeda.

Within the largest group — married working mothers — researchers found very similar memory trajectories for those who worked continuously and those who took time off to stay home with children before re-entering the workforce.

"This is a really intriguing finding," said Mayeda. "You might naturally assume that there would be a dose response; that if work is protective, you have to spend your entire adulthood working to reap the benefits."

The mechanisms behind the cognitive benefits of paid work for women aren't clear, said Mayeda. However, she believes the cognitive stimulation that work provides could play a role as well as the related social engagement and financial rewards of receiving a regular paycheck, which may provide greater independence for women.

Investigating whether women's current SES helps explain the protective effect of work could be a "next step" for the research team, said Mayeda.

The new results suggest that policies and programs that facilitate participation of women in the workforce could be effective strategies to protect memory.

"For example, promoting equal pay for equal work, paid family leave, and affordable childcare could be potential policies to prevent memory decline in later life for women," said Mayeda.

Epicenter of Dementia Epidemic

Commenting on the study for Medscape Medical News, Rebecca M. Edelmayer, PhD, director, scientific engagement, Alzheimer's Association, said it underscores the idea that participating in socially stimulating activities earlier in life can be protective later on.

But more research is needed to understand what types of activities are most protective, she said.

"In this study, they looked at paid work, and we recognize that this has a different way of stimulating the brain than maybe other types of activities. But that doesn't mean it's the only way to stimulate your brain."

Edelmayer noted that the interplay between genetics and modifiable risk factors, including cognitive reserve and cognitive resilience, and risk factors that can't be changed such as age, could be an important determinant of memory decline. Social factors could also play a role, she said.

The moderator of the press briefing that featured this study, Suzanne Craft, PhD, a member of the Alzheimer's Association's Medical and Scientific Advisory Group, said it's "imperative" to determine the basis for the "disproportionate risk" of AD in women.

Women are at the epicenter of the AD epidemic, said Craft, who is professor, gerontology and geriatric medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina. She added that women are not only much more likely than men to develop AD but also to be caregivers to those living with AD.

Craft noted that the Alzheimer's Association invested more than $3.2 million over the last few years in research looking at sex-specific differences in AD risk.

The study received funding from the National Institute on Aging. Mayeda and Edelmayer have reported no relevant financial disclosures.

AAIC 2019. Presented July 16, 2019. Abstract 33685.

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