Too much cleanliness can increase the risk of developing Alzheimer's disease, according to a new research report.
A hygienic atmosphere is normally considered vital for healthy growth. However, Dr Molly Fox and her colleagues from the University of Cambridge found that an extremely hygienic atmosphere left a negative impact on the immunity system, further increasing the risk of Alzheimer's disease, one of the most common causes of dementia.
People living in industrialised and wealthy countries with better sanitation had greater risks of the brain disorder, due to their excessive cleanliness and lack of exposure to different kinds of bacteria, viruses and other microorganism, that help the body to build a strong immune system.
Researchers reached the conclusion after analysing prevalence of Alzheimer's disease in 192 countries, and comparing the rates to factors like life expectancy, birth rate and age.
The disease that destroys memory was more prevalent among countries that had improved sanitation facilities like clean drinking water. UK and France had a nine percent higher rate than Kenya and Combodia. Countries with lower rates of infectious diseases like Switzerland and Iceland had 12 percent higher rate than China and Ghana. Highly urbanised countries like UK and Australia had 10 percent higher rates than Nepal and Bangladesh.
The researchers stated that their study is another solid evidence to prove the "hygiene hypothesis"- a common theory upheld by allergists that over sanitization at childhood may be weakening the immune system, increasing the risks of many allergies.
"The 'hygiene hypothesis', which suggests a relationship between cleaner environments and a higher risk of certain allergies and autoimmune diseases, is well- established. We believe we can now add Alzheimer's to this list of diseases," lead author of the study, Fox , said in a university news release.
"There are important implications for forecasting future global disease burden, especially in developing countries as they increase in sanitation."
The findings support a previous study which found that increase in dementia cases were slow in low-income, developing countries, compared to the industrialised countries.
Lack of exposure to the bacteria affects proper development of white blood cells, particularly the T-cells that protect the body against many diseases and infections.
The study has been published in the journal Evolution.
Below is a video of Dr Molly Fox talking about the study: