Mark Holbreich, MD

Exploring Hygiene Hypothesis in Amish Community 

National Jewish Health former fellow (79-81) Mark Holbreich, MD, began to offer free allergy clinics in the 1980s to the Amish community in Northern Indiana. "The Amish accept no insurance and live a life separate from the ‘outside world,'" said Dr. Holbreich. "They are committed to a traditional agrarian lifestyle and their faith."

Dr. Holbreich noticed that the majority of the 20 to 30 patients who visited each clinic had no evidence of food or inhalant allergy, eczema, allergic rhinitis or asthma. Skin tests were often negative. His observations were different from the experience in his Indianapolis practice where most patients seeking advice have allergies.

Endotoxin Exposure

In 2000, Dr. Holbreich read National Jewish Health physician Dr. Andy Liu's first observations on endotoxin exposure and allergy prevention. Amish have large families; children are in the barn and around farm animals from a very early age and drink unpasteurized milk. Dr. Holbreich wondered if the Amish community could be exemplifying the hygiene hypothesis. He contacted Dr. Liu and, in 2004, the two doctors together visited an Amish community. Their informal survey found no one with knowledge of any allergic individuals.

"I am grateful and appreciative of Dr. Holbreich's willingness to share his experience," said Dr. Liu. "While I came out of scientific interest, I left with a profound admiration for the Amish way of life. There may be benefits of the Amish lifestyle that go beyond early endotoxin exposure to account for the low incidence of atopy."

Cooperation among former fellows and current faculty is a great strength of the National Jewish experience. Drs. Liu and Holbreich continue to work together on ways to further define the incidence of allergic disease in the Amish population and to explore what can be learned about prevention and well-being from this unique community.