NEW YORK, May 10 (Reuters Health) - Imaging studies of the brains of
Alzheimer's patients suggest that damage to the brain's white matter is more
common and more severe in women than men, Japanese researchers report.
Moreover, a gene called apoE4 was "not associated with the presence or the
degree of cerebral white matter (damage) in Alzheimer's disease," as had been
theorized, according to Hideyuki Sawada of Kyoto University in Japan, and
colleagues. ApoE4 is a gene variant involved in regulating production of
apolipoprotein E, a protein that functions in the transport and metabolism of
various fatty substances. Carrying apoE4 is known to confer an increased risk of
developing Alzheimer's.
Characterized by a progressive dementia, Alzheimer's is a debilitating
disorder that features a distinct kind of damage to the white matter of the
brain. Sawada and the multicenter team looked at whether these white matter
injuries could be linked in some way to the apoE4 variant, since the gene has
also been implicated in similar kinds of brain damage.
The team also examined whether factors such as "sex, age...hypertension,
(or) diabetes mellitus" might play a role in mediating the white matter damage.
The study subjects included 55 patients with the disease and 66 healthy
subjects.
The investigators found that over 65% of the Alzheimer's patients had the
tell-tale white matter damage. But, they were unable to demonstrate a
'statistically significant relation between the E4 (gene variant) frequency and
the lesion grades."
However, a "significant risk factor for the presence of white matter
(damage) is sex"--that is, white matter lesions were more common in female
patients, the study authors write in the Journal of Neurology, Neurosurgery and
Psychiatry. The researchers also note that these lesions were usually more
severe in female patients compared with males.
While Sawada's team can offer no sure explanation for this sex difference,
they theorize that "the estrogen decline in menopausal women may be related to
the degenerative damage in the cerebral white matter." They call for more
research to explore this apparent white matter damage difference between the
sexes.
