Family history and the risk of early-onset persistent, early-onset transient, and late-onset asthma.
Family history of asthma and allergies strongly influences asthma risk in children, but the association may differ for early-onset persistent, early-onset transient, and late-onset asthma. We analyzed the relation between family history and these types of asthma using cross-sectional data from a school-based study of 5,046 Southern California children. Parental and/or sibling history of asthma and allergy were generally more strongly associated with early-onset persistent asthma compared with early-onset transient or late-onset asthma. For children with two asthmatic parents relative to those with none, the prevalence ratio for early-onset persistent asthma was 12.1 [95% confidence interval (CI) = 7.91-18.7] compared with 7.51 (95% CI = 2.62-21.5) for early-onset transient asthma and 5.38 (95% CI = 3.40-8.50) for late-onset asthma. Maternal smoking in pregnancy was predominantly related to the risk of early-onset persistent asthma in the presence of parental history of allergy and asthma, and the joint effects were more than additive (interaction contrast ratio = 3.10, 95% CI = 1.45-4.75). Our results confirm earlier data that parental history of asthma and allergy is most strongly associated with early-onset persistent asthma and suggest that among genetically predisposed children, an early-life environmental exposure, maternal smoking during pregnancy, favors the development of early-onset asthma that persists into later early childhood.
London
S J
SJ
Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
James Gauderman
W
W
Avol
E
E
Rappaport
E B
EB
Peters
J M
JM
D000293:Adolescent; D001249:Asthma / Q000145:classification / Q000453:epidemiology* / Q000209:etiology / Q000235:genetics; D002140:California / Q000453:epidemiology; D002648:Child; D005190:Family; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D015995:Prevalence; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*