Written By: Cameron Scott
Posted: 09/18/13 8:18 AM
Few would argue the overall health benefits of living in the industrialized world. Clean drinking water, fewer fatal accidents and greatly reduced infant mortality are just a few of the advantages. So pronounced are the health boons of development that researchers may sometimes be blinded to health risks that it brings.
For example, rates of Alzheimer’s disease are higher in developed nations — a fact that is often attributed to the longer life expectancies in those countries. But the higher rates persist even after correcting for longer lifespans, according to a recent study led by Cambridge evolutionary biologist Molly Fox.
With that in mind, it seems there must be health threats in the developed world that aren’t present in countries that have stuck to their agrarian traditions. Fox’s study suggested that, paradoxically, the improved sanitation in developed countries may leave residents more exposed to Alzheimer’s disease.
The study is apparently the first to link Alzheimer’s disease to an increasingly accepted theory called the hygiene hypothesis.
The hypothesis posits that people in industrialized societies don’t come into contact with enough bacteria to spur their immune systems to develop fully. Some, like Fox, focus on the development of germ-killing T-cells in young children.
The hygiene hypothesis has previously been cited as a possible cause for autoimmune disorders, allergies, asthma and even diabetes — all of which have increased rapidly enough to defy conventional explanations.
“In the modern developed world, we live in hygienically sanitized environments, and as a result we’re not in contact with animals, feces and mud, which would have been the norm for the vast majority of human history,” Fox said in a video about the findings, published in published in Evolution, Medicine and Public Health.