Risk factors of Alzheimer's disease
Alzheimer’s disease is a brain disease that mainly affects people later in life. It causes steep declines in memory and other cognitive functions. At advanced stages, the brain shuts down and the person dies. There is no cure or effective treatment for Alzheimer’s disease. Alzheimer’s disease changes the structure of the brain and can be observed in autopsy by (a) neurofibrillary tangles (NFTs), and (b) amyloid plaques. The disease seems to come on slowly, causing structural changes long before it can be detected. Neurologists are able to diagnose Alzheimer’s disease and work with patients and family members to develop tools and systems to deal with the disease.
A recent review of Alzheimer’s disease risk factors (Bendlin et al. 2010) proved very insightful:
Risk factor #1: Genetic risk & family history
Some people may be genetically predisposed to Alzheimer’s disease (or other diseases). For example, it was recently in the news that actor Chris Hemsworth has some sort of genetic marker that makes him far more likely to acquire the disease as he ages. Nothing can currently be done about genetic risk factors but scientists are working on a tool called CRISPR that they have successfully used in some cases to edit peoples’ gene sequences, curing them of genetic diseases. Offspring of parents with Alzheimer’s disease have six time greater risk for developing the disease compared to those without a family history of the disease.
Risk factor #2: Sex
The incidence of Alzheimer’s disease in women is 1.5–3 times higher than the incidence in men. Women’s increased risk for AD coincides with menopause, implicating estrogen deficiency as the primary sex-related risk factor for Alzheimer’s disease.
Risk factor #3: Midlife health factors
Obesity at mid-life is associated with over a 3x increase in likelihood of developing Alzheimer’s disease later in life. Hypertension at mid-life is also associated with a higher likelihood of developing the disease.
Using data from the population-based Cardiovascular Risk Factors, Aging, and Dementia (CAIDE) study (n = 1409), Kivipelto and colleagues confirmed that increased vascular risk at midlife predicted dementia 20 years later . Kivipelto et al. constructed a baseline risk score composed of body mass index, systolic blood pressure, diastolic blood pressure, total cholesterol, current smoking status, and level of physical activity. The risk of dementia for those with the highest baseline risk score was 16.4%, compared to only 1% for those with the lowest risk score. Of the factors comprising the overall risk score, hypertension, hypercholesterolemia, and obesity were the most predictive of dementia.
Midlife health factors appears to be the strongest signal of all the risk factors.
Risk factor #4: Environmental and lifestyle factors
Several more studies show a connection between eating healthy, exercising, having healthy social relationships, etc. and a decrease in the occurrence of Alzheimer’s disease.
The occurrence of Alzheimer’s disease can be reduced by taking care of yourself. Eat healthy, try to keep your weight down, exercise, stop smoking, and make an effort to maintain positive relationships for the best benefits.
Bendlin, B. B., Carlsson, C. M., Gleason, C. E., Johnson, S. C., Sodhi, A., Gallagher, C. L., … Asthana, S. (2010). Midlife predictors of Alzheimer’s disease. Maturitas, 65(2), 131–137. doi:10.1016/j.maturitas.2009.12.014