Asthma and Farm Exposures in a Cohort of Rural Iowa Children

Abstract

Epidemiologic studies of farm children are of international interest because farm children are less often atopic, have less allergic disease, and often have less asthma than do nonfarm children—findings consistent with the hygiene hypothesis. We studied a cohort of rural Iowa children to determine the association between farm and other environmental risk factors with four asthma outcomes: doctor-diagnosed asthma, doctor-diagnosed asthma/medication for wheeze, current wheeze, and cough with exercise. Doctor-diagnosed asthma prevalence was 12%, but at least one of these four health outcomes was found in more than a third of the cohort. Multivariable models of the four health outcomes found independent associations between male sex (three asthma outcomes), age (three asthma outcomes), a personal history of allergies (four asthma outcomes), family history of allergic disease (two asthma outcomes), premature birth (one asthma outcome), early respiratory infection (three asthma outcomes), high-risk birth (two asthma outcomes), and farm exposure to raising swine and adding antibiotics to feed (two asthma outcomes). The high prevalence of rural childhood asthma and asthma symptoms underscores the need for asthma screening programs and improved asthma diagnosis and treatment. The high prevalence of asthma health outcomes among farm children living on farms that raise swine (44.1%, p = 0.01) and raise swine and add antibiotics to feed (55.8%, p = 0.013), despite lower rates of atopy and personal histories of allergy, suggests the need for awareness and prevention measures and more population-based studies to further assess environmental and genetic determinants of asthma among farm children.

Food System Policy, Public Health, and Human Rights in the United States

“…IFAP operations, for example, may introduce nitrates, microbial pathogens, veterinary pharmaceuticals, hormones, and other contaminants into groundwater and surface water-often via the application of animal waste-thus contributing to a range of adverse health and ecological effects (19). Air degradation: IFAP operations are frequently associated with elevated indoor and downwind concentrations of airborne pollutants, including ammonia, hydrogen sulfide, and airborne particulates, which contribute to respiratory illnesses and other adverse health effects among workers, their families, and nearby residents (64,101,105,138). Similarly, pesticide applications may present health risks to agricultural workers (20) and nearby residents (93,146).…”

Characterisation of asthma among adults with and without childhood farm contact

“…Several studies [2][3][4][5][6] have shown that growing up on a farm is associated with a lower prevalence of sensitisation and hay fever among children, a fact that backs up the hygiene hypothesis. Different studies [7][8][9][10][11] have suggested that the effect of childhood farm living on sensitisation and hay fever may persist until adulthood.…”

Expressing urine from a gel disposable diaper for biomonitoring using phthalates as an example

“…Merchant and co-workers (2005) found that exposure to farm animals early in life was not protective against asthma. Those children living on farms that raised swine actually had significantly higher rates of diagnosed asthma and/or asthma symptoms compared with those not living on farms or those living on farms that did not raise swine (Merchant et al, 2005). These authors suggested that previous studies that considered only doctor-diagnosed asthma may have underestimated the true prevalence of asthma among farm children (Merchant et al, 2005).…”