Being too clean apparently has its negative effects, as research findings show that good hygiene is linked with Alzheimer's disease, reports Red Orbit.

Considered to be a debilitating cognitive and intellectual deterioration, Alzheimer's disease is most prevalent among seniors. It affects the brain and causes the patient to lose the ability in managing daily tasks. It impairs a person's memory, language skills, reasoning ability and social skills, according to the CDC.  In the U.S., it is estimated that over 5 million adults have this type of dementia.

Scientists are continuously researching for the cause of Alzheimer's disease, and research conducted by University of Cambridge's Biological Anthropology division found that there is a close link between this disease and the practice of good hygiene in highly-industrialized nations. 

Lead author Dr. Molly Fox explained that individuals in highly-developed countries such as the U.S. have substantially lesser exposure to viruses, bacteria, and other microorganisms, so that their immune system develops poorly. A weak immune system increases the risk of having dementia such as Alzheimer's disease, according to Red Orbit.

Fox's research team used age-standardized data to discover the strong parallelism and correlation between the disease and national sanitation levels in highly-industrialized countries. Age-standardized data predicts the rate of progression of Alzheimer disease given the condition that countries 'had the exact same population birth rate, life expectancy and age structure,' according to Mail Online.

The result led the research team to believe that the "hygiene hypothesis" is key in understanding this particular dementia. Dr. Fox explained that, "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. There are important implications for forecasting future global disease burden, especially in developing countries as they increase in sanitation," reports Mail Online.

The study is published in the journal, Evolution, Medicine and Public Health.