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

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 IgE > 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.

Is yoghurt an acceptable alternative to raw milk for reducing eczema and allergy in infancy?

“…The effect estimates in both these studies and ours are substantial, suggesting a 50%-80% reduction for eczema and sensitization. This is of similar magnitude to the studies of the protective benefits of farming exposures or raw milk consumption, 11 where both exposures in early life have been associated with substantial reductions in sensitization and allergic disease in later childhood.…”

“…Early daily yoghurt consumption appears to reduce eczema and early atopic sensitization particularly to food antigens. In this regard, yoghurt is a safe alternative to raw milk (which has been repeatedly associated with reduced allergy) and is already available around the world. Indeed, unsweetened plain yoghurt is already encouraged as an infant food (from 6 to 7 months of age) by a number of expert groups including the World Health Organization, the National Health Service (UK) and in New Zealand by the Ministry of Health.…”

“…Early daily yoghurt consumption appears to reduce eczema and early atopic sensitization particularly to food antigens. In this regard, yoghurt is a safe alternative to raw milk (which has been T A B L E 1 Associations of yoghurt consumption with eczema and atopic sensitization, adjusted for study treatment, gender, preterm delivery (<37 wk), caesarean delivery, pets in home at birth, breastfeeding duration, number of previous pregnancies>20 wk of gestation and antibiotics during each yoghurt consumption period repeatedly associated with reduced allergy) 11…”

Allergic asthma: an overview of metabolomic strategies leading to the identification of biomarkers in the field

“…During the prenatal period, while the development of the airway and immune system, maternal exposure to tobacco smoke, trafficrelated pollutants, viral infection or dust mites have been shown to increase the risk of asthma in offspring [38][39][40][41]. acetaminophen) have been shown to elevate childhood asthma risk [42][43][44]. acetaminophen) have been shown to elevate childhood asthma risk [42][43][44].…”

“…The second critical period for asthma onset is throughout early childhood, especially in the first year of life (during alveolar expansion and rebalancing of the immune responses), where severe viral infections in the inferior respiratory tract or the exposure to airborne environmental irritants, HDM allergens and therapeutics (e.g. acetaminophen) have been shown to elevate childhood asthma risk [42][43][44]. Another marker currently used in medical daily practice to identify severe phenotypes is the fraction of exhaled nitric oxide (NO).…”