Psychophysiologic impacts of odor from industrial hog operations on nearby residents

The rapid proliferation of industrial hog operations (IHOs) since the 1970s has generated numerous health concerns. Effects on physical health of occupational exposure to confinement house dusts and gases have been examined extensively. However, health effects among persons living in close residential proximity to such facilities have only recently been studied. Cold and flu-like symptoms, gastrointestinal illness, mucous membrane irritation, and effects on mood have been documented in several studies of neighbors, though residential exposures to airborne emissions are likely orders of magnitude lower than occupational exposures. We have therefore chosen to evaluate the hypothesis that exposure to malodor from IHOs has a psychophysiologically mediated effect on health, specifically that malodor as a stressor exerts an immunosuppressive effect on secretory immunoglobulin A (sIgA). Seventy-two predominantly African-American adults who lived within 1.5 miles of at least one IHO in eastern North Carolina collected data twice daily for two weeks; they rated the intensity of malodor, stress, and adverse mood on a 9-point scale and provided saliva samples that were later analyzed for sIgA content. We used hierarchical models to examine the relationships between malodor, reported stress, and sIgA secretion rate (μg/min), with each participant serving as his or her own control. We observed decreased sIgA secretion rates at the highest levels of malodor and reported stress, adjusted for time of day. The effects were more pronounced in women, in participants with a better sense of smell, and in participants who scored higher on the John Henryism Active Coping scale.