Asthma and farm exposures in a cohort of rural Iowa children.
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.
Merchant
James A
JA
Department of Occupational and Environmental Health, University of Iowa College of Public Health, Iowa City, Iowa, USA. james-merchant@uiowa.edu
Naleway
Allison L
AL
Svendsen
Erik R
ER
Kelly
Kevin M
KM
Burmeister
Leon F
LF
Stromquist
Ann M
AM
Taylor
Craig D
CD
Thorne
Peter S
PS
Reynolds
Stephen J
SJ
Sanderson
Wayne T
WT
Chrischilles
Elizabeth A
EA
D000293:Adolescent; D000383:Agriculture; D001249:Asthma / Q000209:etiology* / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007484:Iowa / Q000453:epidemiology; D008297:Male; D008962:Models, Theoretical; D012129:Respiratory Function Tests; D012307:Risk Factors; D012424:Rural Population; D012737:Sex Factors; D016896:Treatment Outcome
Appl Occup Environ Hyg. 2003 Jun;18(6):418-29
12746065
J Agromedicine. 2006;11(3-4):15-24
19274894
Am J Respir Crit Care Med. 2000 May;161(5):1563-6
10806155
J Expo Anal Environ Epidemiol. 2004 Mar;14(2):180-7
15014549
Clin Exp Allergy. 2001 Apr;31(4):570-5
11359424
Clin Exp Allergy. 2003 Jun;33(6):770-6
12801311
Clin Exp Allergy. 1999 Jan;29(1):28-34
10051699
Environ Health Perspect. 2000 Mar;108(3):233-8
10706529
Am J Clin Nutr. 1991 Apr;53(4):839-46
2008861
Thorax. 1998 Nov;53(11):927-32
10193389
Clin Exp Allergy. 2000 Feb;30(2):201-8
10651772
Am J Respir Crit Care Med. 2001 Feb;163(2):322-8
11179100
Allergy. 2002 Dec;57(12):1171-9
12464046
Am J Respir Crit Care Med. 2001 Feb;163(2):305-6
11179094
Am J Respir Crit Care Med. 1995 Jan;151(1):47-53
7812571
Clin Exp Allergy. 1999 Jun;29(6):766-71
10336592
Environ Health Perspect. 2003 Oct;111(13):1590-4
14527837
Am J Respir Crit Care Med. 2000 Jan;161(1):309-29
10619836
Lancet. 2001 Oct 6;358(9288):1129-33
11597666
J Sch Health. 1999 Jan;69(1):12-6
10098113
Lancet. 2004 Jan 10;363(9403):119-25
14726165
J Pediatr. 1993 Aug;123(2):223-9
8345417
Eur Respir J. 1998 Aug;12(2):315-35
9727780
Am J Respir Crit Care Med. 2001 Nov 15;164(10 Pt 1):1829-34
11734431
Clin Exp Allergy. 1998 Apr;28 Suppl 1:13-4; discussion 32-6
9641584
Am J Respir Crit Care Med. 1999 Mar;159(3):760-7
10051248
Clin Exp Allergy. 2000 Feb;30(2):187-93
10651770
J Allergy Clin Immunol. 2003 Dec;112(6):1072-7
14657861
J Allergy Clin Immunol. 2004 Jan;113(1):66-71
14713909
Am J Ind Med. 1996 Jan;29(1):33-40
8808040
Clin Exp Allergy. 2000 Feb;30(2):194-200
10651771
Am J Respir Crit Care Med. 1995 Sep;152(3):1107-36
7663792
Am J Ind Med. 2001 Jun;39(6):608-15
11385645
Environ Health Perspect. 2004 May;112(6):760-5
15121522
Am J Respir Crit Care Med. 1998 Nov;158(5 Pt 2):S1-S76
9817727
Nat Genet. 2000 Jun;25(2):187-91
10835634
J Rural Health. 2002 Fall;18(4):521-35
12380895
Clin Exp Allergy. 2003 Mar;33(3):273-6
12614436