Memory Game Changer: Education May Help Close the Gender Gap in Aging Brains

In a groundbreaking study recently published in the Alzheimer's & Dementia Journal, researchers sought to uncover whether educational attainment could influence gender disparities in memory function among the elderly in India in comparison to the United States.

Introduction to the research

As both the United States and India experience a rapid increase in their aging populations, an understanding of cognitive aging and its implications on overall health is becoming critical. By 2050, it is projected that 20% of the population in the United States and 19% in India will be aged 65 and above. With this demographic shift, there's an expected surge in cognitive impairment and dementia within these populations. Conducting a cross-national comparison offers a unique lens through which researchers can explore the reasons behind varying patterns of cognitive outcomes and potentially inform strategies to mitigate the growing global burden of dementia. Such research is of paramount importance due to the significant differences between the two countries in terms of economic, health, and cultural factors, which include variables like early-life education, literacy, employment, and environmental risks.

Prior research

Before this study, past research hinted at cognitive disparities between genders in low- and middle-income countries, with women often at a disadvantage compared to men, a trend less evident in high-income nations. In the United States, it has been found that women generally possess stronger verbal memory skills than men, while men tend to have more robust visuospatial abilities. Intriguingly, although women on average start with higher baseline cognitive scores, they also exhibit a faster decline in cognition and executive function as they age. In contrast, in India, studies have consistently shown that older women have worse outcomes across all cognitive domains, especially among the oldest age groups. Notably, when education levels are equal, Indian women perform comparably or better than men on cognitive tests that don't require literacy, while falling behind on tests that do.

This dichotomy in cognitive outcomes between American and Indian women may reflect broader societal gender inequities prevalent in these countries. For instance, the Gender Inequality Index—a composite measure evaluating the disparity between men and women—showcases greater inequality in India compared to the United States. Given these observations, and considering that education is a known protective factor against dementia risk, researchers have highlighted the significant educational attainment gap between genders in India, where 70% of women, as opposed to 58% of men, have no upper secondary education. The lack of comparative research on how cognitive function differs for older Indian adults by gender and education, relative to their American counterparts, exemplifies a critical knowledge gap regarding gender-based disparities in cognitive aging both within and across nations.

Methods and Results

To address this gap, researchers used data from harmonized cognitive assessment protocols from the Longitudinal Aging Study of India-Diagnostic Assessment of Dementia (LASI-DAD) and the U.S. Health and Retirement Study (HRS-HCAP). This involved 7,443 participants—4,096 from India (2017-2019) and 3,347 from the U.S. (2016-2017). They utilized confirmatory factor analysis to derive harmonized memory factors from each study and then applied multivariable-adjusted linear regression to compare gender disparities in memory function across both countries, adjusting for educational levels.

Intriguingly, the findings revealed a stark contrast: in the United States, older women exhibited better memory function than older men, with a 0.28 standard deviation unit difference favoring women. However, in India, the reverse was true; older women had worse memory function than older men, with a disparity measured at a -0.15 standard deviation unit difference. This gender gap in memory function significantly attenuated with increasing levels of education and literacy among the Indian participants.

Conclusion and implications

The study concluded that education and literacy might play a pivotal role in moderating the gender disparities in memory observed in India—a trend not present in the United States. This crucial finding underscores the importance of educational access and literacy in potentially reducing cognitive inequities across genders. As such, this work importantly contributes to understanding how early-life gender disparities could shape cognitive outcomes later in life. The study suggests that future research should broaden the evidence on the impact that early-life gender inequalities have on later-life cognitive outcomes, particularly across different social and economic settings.

Overall, this research serves as a vital step in grasping the nuanced ways in which societal structures and access to education can affect our cognitive health as we age, with profound implications for addressing and possibly preventing cognitive decline due to gender disparities.