The number of cases of Alzheimer's disease has grown alarmingly to about 34 million people worldwide, and researchers predict this number could increase 3-fold in the next 40 years.
A new study has estimated how many Alzheimer’s cases might be attributable to certain behaviors or conditions (risk factors). This study offers some hope that the causes may be identified in the future to help prevent this disease.
However, causes were not established by the study, which only identified associations between the risk factors and subsequent development of Alzheimer's disease. The modellng study found that more than half of all Alzheimer's cases studied were associated with risks that are lifestyle related and so are preventable.
The Seven Sins identified as risk factors that appeared to predispose subjects to developing Alzheimer's disease were:
The researchers excluded risk factors such as nutrition or brain exercise such as doing puzzles and cross-words because they believed the research date were inadequate.
In the United States, their model estimated that about:
The estimates worldwide were different because some behaviors and conditions are more common worldwide than in the United States.
In the world as a whole, approximately:
The results predicted that reducing the incidence of all these factors by a quarter could possibly prevent about 3 million cases of Alzheimer's disease from developing throughout the world, if the risks were causal or contributed to the development of the disease.
In 2010, a panel of experts from the National Institutes of Health (NIH) conducted a review National Institutes of Health (NIH) undertook an extensive review of the published studies and found no quality scientific data to support any association with the commonly suggested risk factors. These included various foods and diets, brain exercise, nutritional supplements, herbal medicines, economic and social factors, various prescription drugs and other medicines, associated medical conditions and ailments, toxins and various environmental linkages. For more on this see:see: NIH says science is lacking for Alzheimer's prevention.
The major challenge like many similar studies is to extend beyond establishing an association to confirming the factor as a cause. Many previous studies have looked at certain characteristics that subjects had before developing the disease, but could not proved that the characteristics were causal. For example, the issue is whether depression can lead to Alzheimer’s disease or is it the other way round that people who are developing the disease are depressed.
As Dr. Martha Daviglus, chair of the 2010 NIH panel put it:
"... examples of the classic chicken or the egg quandary. Are people
able to stay mentally sharp over time because they are physically active and socially engaged or are they simply more likely to stay physically active and socially engaged because they are mentally sharp?" she asked.
The jury is still out on what causes Alzheimer's disease and what to do to prevent it.
However, the latest study is interesting as it establishes links with some of modern society's sins such as smoking, diabetes, being overweight and unfit which offers some hope that the disease can be prevented.