Format

Send to

Choose Destination
J Allergy Clin Immunol. 2017 Jul;140(1):249-256.e14. doi: 10.1016/j.jaci.2016.09.036. Epub 2016 Nov 12.

Early-life farm exposures and adult asthma and atopy in the Agricultural Lung Health Study.

Author information

1
Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC.
2
Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC; Department of Biological Sciences, Center for Human Health and the Environment, North Carolina State University, Raleigh, NC.
3
Westat, Durham, NC.
4
Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV.
5
Occupational and Environmental Epidemiology Branch, National Cancer Institute, Bethesda, Md.
6
Epidemiology Center, Public Health Sciences, Social & Scientific Systems, Inc, Durham, NC.
7
Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC. Electronic address: london2@niehs.nih.gov.

Abstract

BACKGROUND:

Previous studies, mostly from Europe, suggest that early-life farming exposures protect against childhood asthma and allergy; few data exist on asthma and allergy in adults.

OBJECTIVE:

We sought to examine associations between early-life farming exposures and current asthma and atopy in an older adult US farming population.

METHODS:

We analyzed data from 1746 farmers and 1555 spouses (mean age, 63) from a case-control study nested within the Agricultural Health Study. Current asthma and early-life farming exposures were assessed via questionnaires. We defined atopy based on specific IgEĀ > 0.70 IU/mL to at least 1 of 10 allergens measured in blood. We used logistic regression, adjusted for age, sex, race, state (Iowa or North Carolina), and smoking (pack years), to estimate associations between early-life exposures and asthma (1198 cases and 2031 noncases) or atopy (578 cases and 2526 noncases).

RESULTS:

Exposure to the farming environment in utero and in early childhood had little or no association with asthma but was associated with reduced odds of atopy. The strongest association was seen for having a mother who performed farm activities while pregnant (odds ratio, 0.60; 95% CI, 0.48-0.74) and remained significant in models with correlated early-life exposures including early childhood farm animal contact and raw milk consumption.

CONCLUSIONS:

In a large US farming population, early-life farm exposures, particularly maternal farming activities while pregnant, were strongly associated with reduced risk of atopy in adults. These results extend previous work done primarily on childhood outcomes and suggest that protective associations of early-life farming exposures on atopy endure across the life course.

KEYWORDS:

Agriculture; IgE; agricultural workers' diseases; allergy and immunology; asthma; hygiene hypothesis; prenatal exposure delayed effects

PMID:
27845237
PMCID:
PMC5429211
DOI:
10.1016/j.jaci.2016.09.036
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center