Improvements in access to education for girls over the last
century in the UK are likely to have reduced differences in
cognitive ageing between men and women, potentially reducing sex
disparities in dementia risk, finds a new large cohort study led
by UCL.
Though previous research indicates women are at higher risk
of dementia than men, the study, published today inThe Lancet
Public Health,found
thathistoricalinequalities in levels of
education were partially responsible for differences in cognitive
ageing between men and women, potentially contributing to sex
disparities in dementia risk.
Using combined data from theEnglish
Longitudinal Study of Ageing (ELSA) and the Whitehall II
study,the researchers assessed the impact of
education and birth cohort on differences in both ‘memory’ and
‘fluency’ trajectories of15,924
participantsborn between1930 and
1955.
Memory was assessed by asking participants to memorise a
list of words and then recall as many as possible within two
minutes. Fluency was assessed by asking participants to list as
many animals as possible within one minute.
Overall,the team found that women performed
better than men on the memory test, with more marked differences
found in women born more
recently.Furthermore,women were also
found to experience slower rates of memory decline than
men.
Women were found to have poorer fluency scores than men in
the older birth cohort, yet this difference progressively
reversed in more recent birth cohorts, with women born between
1946 and 1955 having better scores than their male counterparts.
The researchers found thatthese changes could be
partially explained by an increase in education level in women
born later; whilst men were more likely than women to have high
education level across all birth cohorts, women’s education level
increased with each successive birth cohort.
Given that poor performance on memory and fluency tests is
strongly associated with dementia, the authors conclude
thatincreases in educational opportunities driving
improvements in midlife cognition for women may therefore reduce
sex differences in dementia risk for future generations.
Carried out with researchersat the French
National Institute of Health and Medical
Research,the study is thought the be
thefirst of its kind at this scale to
comprehensively assess sex differences in cognitive outcomes that
also examines the role of secular (long-term) changes in
education.
Lead author, PhD candidate Mikaela Bloomberg (UCL
Department of Epidemiology and Public Health), said: “Our
findings suggest that among people educated in the first half of
the 20th century, gender inequalities in access to education led
to lower education levels among women and this likely negatively
impacted cognitive ageing and therefore increased the risk of
dementia for women. Our study suggests this might change in the
future, as disparities in access to education decrease,
highlighting the importance of equitable access to education for
health, particularly in countries where access to education for
women and girls is still limited.”
Co-author, Dr Séverine Sabia, (UCL Department of
Epidemiology and Public Health) said: “We cannot definitively
conclude at this stage that the differences in dementia risk
between men and women will be reduced, because we have only
studied two components of cognitive function, and education is
not the only factor that influences dementia risk. However, the
trend that emerges here suggests increases in access to higher
levels of education could result in better cognitive ageing and
therefore a reduction in sex differences in risk of dementia in
the future.”
The study funders included the National Institute on Aging,
National Institutes of Health; UK Medical Research Council;
British Heart Foundation; and National Institute for Health
Research.
