The Childhood Allergy Study

cas 1 logoCAS II logo

The Childhood Allergy Study (CAS I), a birth cohort study initiated in 1987, and its 18-year follow-up sister study, CAS II, are research projects funded by the National Institutes of Health (NIH) that sought to explore how allergies develop in early life.

Established in metropolitan Detroit with a participant pool of more than 800 pregnant women, specific aims of the study included examining relationships between pet ownership during the first years of the infant’s life, various immune and biological markers, and current and lifetime history of self-reported and doctor diagnosed allergic rhinitis and asthma.

A landmark study published in 2002 using data from the study found that exposure to 2 or more dogs or cats in the first year of an infant’s life reduces that infant’s risk of allergic sensitization to multiple allergens during childhood. To date, this influential study has been cited over 400 times and was featured in USA Today and The New York Times and in BBC News – World Edition.

A second article (published in 2011) examining data from a follow-up clinic visit and interview conducted when the child was 18 years of age (CAS II), determined that among males, those with an indoor dog during the first year of life had half the risk of being sensitized to dogs at age 18 compared with those who did not have an indoor dog in the first year of life. This was also true for males and females born via c-section. In addition, it was revealed that teens with an indoor cat in the first year of life had a decreased risk of being sensitized to cats.

Principal Investigators involved in the CAS I study include

  • Dennis Ownby, M.D. - Georgia Health Sciences University
  • Christine Cole Johnson, Ph.D., MPH

Principal Investigators involved in the CAS II study include

  • Edward Zoratti, M.D.
  • Christine Cole Johnson, Ph.D., MPH

Co-Investigators involved in both or either of these studies

  • Kevin Bobbitt, Ph.D.
  • Christine Joseph, Ph.D.
  • Suzanne Havstad, M.A.
  • Edward Peterson, Ph.D.
  • Ganesa Wegienka, Ph.D.
  • Kim Woodcroft, Ph.D.

Please direct any inquiries to the CAS Research Manager, Kyra Jones, at (313) 874-7390,

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