DISCUSSION
In this prospective population-based study of Italian persons with poor education and a rural background, MetS
diagnosed in late life was not associated with a higher risk
of developing dementia and, after age 75, was even associated with a lower risk of incident AD.
Results from previous investigations about MetS and
dementia in elderly persons are scant and contradictory. In a
case-control study,6 the likelihood of having AD was positively associated with MetS and all its components except
for hypertension, which had a negative association. In a cross-sectional population-based investigation of older
Finnish adults,7 MetS was associated with AD in women
but not in men, low HDL-C and hyperglycemia being the
most frequent MetS components in AD cases. Average age
for both these investigations was younger than 75. In a
prospective population-based investigation of JapaneseAmerican men,8 MetS diagnosed at midlife was associated
with risk of developing VaD but not AD after 25 years of
follow-up. By contrast, no association between MetS and
4-year risk of dementia was found in a multiethnic cohort
with an average age of 75 and older.9 In this cohort, diabetes mellitus increased risk of overall dementia and AD,
but abdominal obesity and hypertriglyceridemia lowered it.
Differences in study design, ethnic origin of participants,
and MetS diagnostic criteria (one of the longitudinal studies
did not use standardized MetS criteria8 and the other used a
modified version of the NCEP criteria9) make it difficult to
make a direct comparison of results, but the younger age of
participants at the time of MetS diagnosis might explain the
positive associations with dementia reported in some studies. Evidence of the association between dementia and individual MetS components is strongest at midlife and
becomes less consistent with advancing age.23
To the authors’ knowledge, there are no previous reports of an inverse association between MetS and dementia
in late life, but a report that MetS is associated with decelerated cognitive decline in a cohort of subjects aged 85 and
older supports the finding that AD risk was lower in older
MetS participants.