tHe incidence of aLzHeimeR’s is gReateR in women

Your chances of developing Alzheimer’s disease late in life are somewhat greater if you are a woman than a man. One study followed 16,926 people in Sweden and found that, beginning around age 80, women were more likely to be diagnosed with Alzheimer’s disease than men of the same age. Similarly, a study based in Taiwan found that one’s chances of developing Alzheimer’s disease over seven years was greater in women compared to men. And a meta-analysis examining the incidence of Alzheimer’s disease in Europe found that approximately 13 women out of 1,000 developed Alzheimer’s each year, compared to only seven men.

So, women living longer than men cannot be the whole answer as to why women are more likely than men to develop Alzheimer’s disease, because even among individuals who are living and the same age, women are more likely to be diagnosed with Alzheimer’s than men. The incidence of non-Alzheimer’s dementia is not greater in women.

One clue to the answer to this puzzle is that your chances of developing dementia from a cause other than Alzheimer’s disease is not greater if you are a woman. For example, the study examining dementia rates in Sweden found that both women and men were equally likely to develop a non-Alzheimer’s dementia as they aged. That rates of Alzheimer’s disease differ by gender, whereas rates of non-Alzheimer’s dementias do not, suggests that there must be a specific interaction between Alzheimer’s disease and gender.

amYLoid deposition in aLzHeimeR’s maY be figHting infections

Another clue to this puzzle comes from the work of Harvard researchers, who have suggested that amyloid, one component of Alzheimer’s disease pathology, may be deposited in order to fight off infections in the brain. If their suggestion turns out to be correct, we might think of Alzheimer’s disease as a byproduct of our brain’s immune system.