The risk factors for Alzheimer's disease are many and varied — anything from diabetes and hypertension to advanced age can make you more vulnerable to the condition. Gender is another identified risk factor, and here, we'll take a deeper look into its link to Alzheimer's disease.
What's gender got to do with Alzheimer's disease?
The two most common risk factors for Alzheimer's disease are age and gender. As a person age rises, so does their risk of Alzheimer's disease. The main theory to explain this is an accumulation of damaged proteins — called beta-amyloids — in the brain. These proteins are more likely to "get glitchy" after years of the inflammation and stress often seen in chronic diseases like hypertension and diabetes, as well as natural aging.
Bearing this in mind, it stands to reason that male patients are more likely to be afflicted with Alzheimer's, right? Obesity, hypertension, and diabetes are found in male patients more often. In reality, however, the female gender is associated with a higher risk of developing Alzheimer's disease. This goes a way towards showing that the presence or absence of known risk factors doesn't solely determine whether or not you'll ultimately develop the disease.
Although women seem to have higher rates of Alzheimer's, numerous studies have shown that the prevalence of early-onset AD favors the male gender. This is the form that occurs earlier on in the life of a patient and will typically progress very rapidly.
If you look at the epidemiology statistics of Alzheimer's disease, you'll see that women account for almost 70 percent of cases. On the surface, this gives the impression that Alzheimer's mostly affects women and that men have a much lower risk. There is more to it than that, however.
Women may have higher rates of the disease because they tend to live longer — which means there is more time for misfolded proteins to accumulate in the brain.
Women will also have more severe symptoms and typically deal with more debilitating forms of the disease. In other words, even men and women developed Alzheimer's at equal rates, if a female patient lives 15 years after being diagnosed whereas a male patient will only live seven years, the number of female patients living with Alzheimer's will eventually outnumber the male patients. This can easily make Alzheimer's seem like a condition that predominantly strikes women.
Why are women more likely to have Alzheimer's disease?
Although I already covered one of the elements that can boost the prevalence of Alzheimer's in the female population, there is another theory that can explain why females are also predisposed to the condition. This has to do with the mitochondria found in patients with Alzheimer's disease.
As a refresher to your high school biology days, mitochondria can be thought of as the power house of the cell. They are able to take the sugar that we eat and convert it into the energy our body uses for movement, digestion, and immune responses. Not only are mitochondria responsible for creating energy, they also play a role in the immune system — producing so-called reactive oxygen species (ROS). These ROS are created to help destroy the cell membranes of bacteria and other pathogens so they will not be able to cause an infection.
A side effect of these ROS is that over time, they can also damage other healthy structures within the body. They are able to produce oxidants that can lead to unintentional damage. As a side note, this is why many products in your local supermarket are marketed as anti-oxidants. These beverages and foods help reduce the amount of ROS within the body to help prevent long-term damage.
Mitochondria and the ROS they produce explain why women are more vulnerable to Alzheimer's. In younger females, estrogen levels are relatively high throughout their menses, which protect against the overproduction of ROS. As a woman approaches menopause, however, her estrogen levels fall and the effects of the ROS begin to appear. Because her body was protected from the damage of ROS in her younger years, she does not have the same acquired defenses against the ROS a male patient would have after years of dealing with the same damage.
You may now wonder if estrogen replacement therapy could help. Numerous studies have attempted to find an answer to this question, but so far, not of these studies have shown any results. The estrogens found in hormone replacement therapy are slightly than those the body naturally produces during menses, so this may be the reason why these therapies have a big impact on female patients. Giving a more active form of estrogen like what is seen during a period cycle is also not a good idea, because these compounds can actually increase the risk of cervical and breast cancer so the risk is not worth the reward.
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