Plaques in the brain more likely to be expressed as dementia in women than in men

Researchers from the Rush Alzheimer's Disease Center found that plaques and tangles in the brain, the changes seen in people with Alzheimer's disease (AD), are more likely to be expressed as dementia in women than in men.

In the June 2005 issue of Archives of General Psychiatry, "Sex Differences in the Clinical Manifestations of Alzheimer Disease Pathology," principal investigator Lisa L. Barnes, PhD, sought to determine whether the relation between levels of AD pathology and clinical symptoms of AD differed in men and women. Alzheimer's disease is the leading cause of dementia in older people, she noted. The researchers studied older Catholic nuns, priests, and brothers in the Religious Orders Study, a longitudinal clinicopathologic study of aging and AD. The study involves annual clinical evaluations and brain donation at death. The analyses were conducted on 64 men and 77 women. Women were slightly older at death than men; four cortical regions of the brain were counted, and a global measure of AD was derived.

Barnes found women had more global AD pathology than did men due primarily to more neurofibrillary tangles. "On a global measure of AD pathology that ranged from 0 to three, each additional unit of pathology increased the odds of clinical AD nearly three-fold in men compared with more than 20-fold in women. The findings suggest that AD pathology is more likely to be expressed clinically as dementia in women than in men. Our results suggest that the clinical manifestation of AD is stronger in women than in men."

Barnes says that "Understanding why the association between AD pathology and dementia differs in men and women could yield important clues about the pathophysiology of AD or eventually lead to sex-specific preventive or therapeutic strategies.

Another possibility is that women have a relative lack of some protective factor, such as the estrogen deficiency of postmenopausal women, which could increase their vulnerability to AD pathology."

Barnes suggests more research is needed to explore these and other possibilities.