What causes Alzheimer’s disease? No one knows. Scientists are increasingly finding that it is a combination of many interrelated factors that seems to strongly influence a person’s genetic predisposition to develop this devastating degenerative condition. The top two risk factors of the disease – age and genetics – are beyond people’s control, yet decisive forces in the Alzheimer’s epidemiology.
Rare before age 50, Alzheimer’s afflicts nearly half of all people past the age of 85 – the most rapidly growing portion of the population. By the year 2001, over 4 million living Americans had been diagnosed with Alzheimer’s disease and, barring scientific progress, about 14 million will have it by the middle of this century.
As the disease develops, two key structural changes are often observed in the brain:
1) The build-up of plaque, consisting mostly of beta-amyloid peptides
2) The development of neurofibrillary tangles, generated by phosphorylated tau-proteins.
Increased free radical activity (oxidative stress) appears to fuel Alzheimer’s pathology – acting simultaneously as a mediator, product, and trigger for this “clogging” process and its related neural damage. Furthermore, because Alzheimer’s patients often exhibit increased concentration of heavy metals such as mercury in their blood and brain, toxic exposure is also believed to play an important role.
A very important factor in the treatment of Alzheimer’s is keeping active – both physically and mentally. Walking, tai chi, swimming, reading, playing games and socializing with others are all excellent ways to keep active. In China, old people who are surrounded by a loving family and have grandchildren around have better mental function than those who live alone. We are not saying that you have to live in a crowded house with an extended family to be healthy, but do recommend having a hobby and keeping some excitement in your life.
Although a relationship between a stressful lifestyle, a low level of education and a lack of stimulation has been raised through some studies, experts say such links are not yet definitive but deserving of further study. Despite the unproven associations, what harm could fostering a healthier, less stressful lifestyle be?
Moderate alcohol consumption may reduce the risk. One study found that those drinking under one or two drinks per day had a roughly 50% lower risk of developing the disease, while people drinking more than one or two drinks had a 30% lower risk than non-drinkers. Although a protective effect may be had by consuming alcohol, the advice to drink is still premature. Some people are consuming a modest level of alcohol each day as a preventative measure against heart disease and this study appears to confirm that benefit.
Vaccinations have shown protective and reversal effects. Although promising, it is still unknown if one will be successfully developed for human use.
Results from a ‘smell’ test, though not commonly available, were predictive of who would progress to Alzheimer’s disease. A person’s sense of smell is one of the first parts of the neurological system that Alzheimer’s attacks. All 19 patients with mild cognitive impairment who developed Alzheimer’s over the course of the study had low scores in smelling ability, the study found. None of the 30 individuals who scored well on the test developed Alzheimer’s disease during the follow-up period, which averaged 20 months. These results were preliminary and more testing needs to be done.
There is no protective effect of smoking for men, but for women who are not carriers of the gene APOE 4, there appeared to be a protective effect, claim researchers. However, among women who are carriers of the gene, smoking appears to increase the risk of Alzheimer’s disease.