The 2013 Geoffrey Beene Global Neuro Discovery Challenge* on male/female differences in the presymptomatic, early symptomatic, and late dementia stages of Alzheimer’s Disease (AD), with $100,000 in prize awards, attempts to leverage large sets of clinical data and novel analytical approaches.
The challenge is seeking to encourage multidisciplinary teams to analyze public datasets from the National Institute on Aging and other research centers for differences between men and women in cognition, biomarkers, and progressive neurodegenerative decline due to AD.
Women are disproportionally affected by AD; two-thirds of AD patients in the U.S. States are women. This disparity may be due in part to women’s longer life spans, but recent research in mild cognitive impairment is beginning to point toward differences between men and women in the pathology and progression of this disease. Anatomical, molecular, functional, hormonal, and cognitive differences in the brain between males and females have been reported in many species, including humans.
What biological sex differences in the brain mean for impairments in memory and progressive neurodegenerative diseases such as AD is not known. However, studies are accumulating that show a distinct male/female difference in the onset, course, and presentation of AD.
For example, one study reported that women had more neurofibrillary tangles. Increased AD pathology was associated with a nearly 3-fold increase of clinical AD in men, compared with a more than 20-fold increase in women. These and other data suggest that the same degree of cognitive impairment is associated with greater structural damage in men compared with women.
In the Alzheimer’s Disease Neuroimaging Initiative (ADNI), patients were grouped into three clinical categories (probable AD, amnestic mild cognitive impairment (aMCI), and healthy controls). Men and women in the AD and aMCI groups showed different patterns of decline through time. In another ADNI study of brain atrophy rates, statistical mapping revealed significant age and sex differences, with rates of brain atrophy being about 1.0–1.5% faster in women than in men.
The Mayo Clinic Study of Aging reported that incidence rates for MCI were higher in men than women and suggested that risk factors for MCI should be investigated separately in men and women.
Also, the Australian Imaging Biomarker Lifestyle study of aging reported gender differences in β-amyloid levels, which was associated with worse episodic memory and visuospatial performance in females than in males.