The hygiene hypothesis attempts to explain the increased rates of asthma worldwide as a direct and unintended result of reduced exposure, during childhood, to non-pathogenic bacteria and viruses. It has been proposed that the reduced exposure to bacteria and viruses is due, in part, to increased cleanliness and decreased family size in modern societies. Exposure to bacterial endotoxin in early childhood may prevent the development of asthma, but exposure at an older age may provoke bronchoconstriction. Evidence supporting the hygiene hypothesis includes lower rates of asthma on farms and in households with pets. COUNT 5
QSN1 What hypothesis tries to explain the increased amount of asthma world wide? ANS1 The hygiene hypothesis QSN2 How does the hygiene hypothesis explain the increase in asthma? ANS2 a direct and unintended result of reduced exposure, during childhood, to non-pathogenic bacteria and viruses QSN3 What has caused the reduced exposure in childhood? ANS3 increased cleanliness and decreased family size in modern societies QSN4 What could prevent asthma? ANS4 Exposure to bacterial endotoxin in early childhood QSN5 What is some of the evidence backing the hygiene hypothesis? ANS5 lower rates of asthma on farms and in households with pets.