Onset and persistence of childhood asthma: Predictors from infancy

family history of asthma, asthma onset by 3 years of age was found previous ly to be positively associated with variables from the first year of life, including elevated total immunoglobulin E (IgE), frequent respiratory infec tions, and parenting difficulties. We followed this cohort of genetically a t-risk children to investigate the relationship between factors assessed in infancy and asthma, allergy, and psychological status at school age. Methods. A cohort of 150 children who were at risk for developing asthma we re identified prenatally on the basis of the mothers' having asthma. For 28 children, the father had asthma as well, putting them at bilateral genetic risk. Families primarily were middle and upper middle class Caucasians. Pa rents came to the clinic during the third trimester of pregnancy for assess ments of medical and psychosocial functioning. A home visit took place when the infant was 3 weeks old, when parenting risk was assessed before the on set of any asthma symptoms. Parenting difficulties included problems with i nfant caregiving as well as components of maternal functioning, such as pos tpartum depression and inadequate marital support. Blood was drawn for seru m IgE at 6 months of age. Parents and offspring subsequently came to the cl inic multiple times, with the last clinic visit during the child's sixth ye ar. Follow-up at age 6 involved a clinic visit for allergy and psychosocial evaluations, consisting of interviews and a behavior questionnaire. Sevent y-seven children received the allergy and psychosocial evaluation, 26 recei ved the psychosocial evaluation in the clinic, and 30 families received tel ephone interviews and mailed in questionnaires. Additional monitoring of fa milies by telephone and mail was maintained over the next 2 years, until th e children were 8, to ensure accurate characterization of the course of ill ness. Comprehensive medical records were obtained and reviewed for all heal th care contacts. Children were designated as having asthma when there was documentation in medical records of physician-diagnosed asthma, observed wh eezing, and/or prescription of asthma medications during the time period wh en the child was between 6 and 8 years of age. Parental reports of the occu rrence of asthma corroborated the medical record data. Results. Data regarding asthma status were available for 145 children throu gh 8 years of age. Forty (28%) of the children manifested asthma between 6 and 8 years of age. Among variables previously reported to predict asthma o nset by age 3, 3 proved to have significant univariate relationships with a sthma between ages 6 and 8: elevated IgE levels measured when the children were 6 months of age, global ratings of parenting difficulties measured whe n infants were 3 weeks old, and higher numbers of respiratory infections in the first year of life. Among these offspring of mothers with asthma, pate rnal asthma showed a significant association with asthma between ages 6 and 8. Eczema in the first year was not significantly related to later asthma. Multiple logistic regression showed that the model that best predicted ast hma at ages 6 to 8 from infancy variables included 2 main effects. The adju sted odds ratio for 6-month IgE was 2.15 (1.51, 3.05) and for parenting dif ficulties was 2.07 (1.15, 3.71). Although socioeconomic status (SES) was no t associated with asthma at ages 6 to 8, families of lower SES were more li kely to be rated as having parenting difficulties early in the child's life . The mothers of lower SES breastfed for a shorter period of time and were more likely to smoke during their infant's first year. There were more resp iratory infections during the first year of life among infants whose mother was rated as having more parenting difficulties. Mothers who reported smok ing breastfed their infants for a shorter length of time. Male gender was s ignificantly associated with higher IgE levels when infants were 6 months o f age. Laboratory testing was completed for 77 children at age 6. Total ser um IgE levels were significantly higher for the children with asthma betwee n ages 6 and 8. Skin-prick testing showed that the children with asthma had significantly more positive skin test reactions than did the children with out asthma. Psychosocial interview data at 6 years of age were available fo r 103 families, and behavioral questionnaires were available for 133 famili es. On the basis of 6-year interviews, children with asthma were rated as b eing at greater psychological risk than were the children without asthma. M others' Child Behavior Checklist (CBCL) ratings of their children's behavio r indicated higher internalizing scores for the children with asthma as com pared with the children without asthma. Like the 6-month IgE, 6-year IgE wa s higher for boys. IgE levels measured at 6 months of age were significantl y correlated with 6-year IgE levels. Parenting difficulties measured at 3 w eeks were significantly correlated with 6-year measures of maternal depress ion, CBCL Internalizing score, and Child Psychological Risk (CPR) score. Th ere also were significant correlations among the psychosocial variables ass essed when the children were 6 years of age; maternal depression was signif icantly associated with child CBCL Internalizing score and CPR score, and t he last 2 also were significantly correlated. Multiple logistic regression showed that 2 concurrently measured variables entered the model showing the strongest associations with asthma at ages 6 to 8. The adjusted odds ratio for CPR score was 3.21 (1.29-7.96) and for 6-year IgE was 1.71 (1.04-2.80) . Conclusions. This study of the natural history of childhood asthma focused on the development of asthma into the school-age years in a genetically at- risk group of children. The relationships between biological and psychosoci al variables in the first year and school-age asthma support the formulatio n of asthma as beginning early in life, with the developing immune system i nteracting with environmental influences. The data provide support for the possible contribution of psychosocial factors to asthma onset and persisten ce into childhood.