The Healthy Dairy Worker Study

This partnership study with WSU will enroll new workers in the dairy industry and evaluate microbiome changes over time. We will characterize worker exposures to microbes and allergens and evaluate whether these exposures impart immune benefits (the ‘hygiene hypothesis’), and/or increase risk of disease, including infection and airway inflammation. This study will help identify priorities for preventive interventions and healthy host adaptation to the dairy environment.

While workers on dairy farms have multiple occupational exposures including microbes, dust, and endotoxin, some studies have reported low rates of asthma, atopy, and symptomatic diarrhea among people living and working on farms. The “hygiene hypothesis” or “farm effect” posits that exposures to microbes and allergens on farms may actually have immune benefits, and could be a critical determinant of whether farmworkers remain healthy or develop occupational disease including infection and airway inflammation. A better understanding of the role of particular exposures and host factors in the dairy work environment could lead to more effective interventions including early detection of persons at risk of developing problems. This study will explore this hypothesis by recruiting new hires on dairy farm as well as existing worker and community controls and observing changes in gut and nasal microbiome communities, as well as subject health status, over a two-year period.

This study will help identify priorities for preventive interventions and healthy host adaptation to the dairy environment including infection control practices and understanding vulnerable worker populations in a research to practice (R2P) fashion.
The study will test the following hypotheses:

Hypothesis 1: Occupational exposure to dairy environments and microbes in these environments causes changes in the gut and nasal microbiome that persist over time.
Hypothesis 2: Baseline and subsequent microbiome status in dairy workers may be associated with the health and occupational status of these workers.

Specific Aims

Aim 1. Compare reported health status, gut and nasal microbiome, and respiratory function in a cohort of newly hired dairy workers, as well as comparison groups of community controls and experienced workers.

Aim 2. Over a two-year follow-up period, compare gut and nasal microbiome change between new workers and controls.

Aim 3. Determine whether microbiome components are associated with health status or early work cessation.


Principal Investigator: Peter Rabinowitz, MD, MPH
Associate Professor, Environmental and Occupational Health Sciences
University of Washington

NIOSH 2016-2021


Partners and Advisories
Washington State University, Department of Global Animal Health

Washington State Dairy Federation

UW Center for One Health Research

Brochure: Dairy Farming - Hygiene and Health

Brochure: The Partnership for Dairy Safety and Health

Pilot: Transmission of Microorganisms in Dairy Farms