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Background: Asthma and allergy might influence the choice of keeping pets, leading to apparent protective effects of pets on allergic disease., Objective: We investigated the effects of asthma and allergy on subsequent pet keeping in childhood and adulthood., Methods: Information about asthma and pet keeping at ages 0 to 4, 5 to 15, 20 to 44, and 26 to 56 years was provided by 9812 subjects participating in the 9-year follow-up of the European Community Respiratory Health Survey., Results: In childhood asthma debut at younger than 5 years was associated with less cat keeping at 5 to 15 years (odds ratio [OR], 0.60; 95% CI, 0.44-0.82), an effect only observed when the parents did not have asthma or allergy (P(interaction) = .045). Childhood asthma did not influence adult pet ownership, unless there were adult symptoms. Adults less often acquired cats at follow-up if they had 3 or more asthma symptoms (OR, 0.78; 95% CI, 0.64-0.95), were taking asthma medication (OR, 0.48; 95% CI, 0.31-0.74), had hay fever (OR, 0.75; 95% CI, 0.62-0.91), had atopy (OR, 0.75; 95% CI, 0.61-0.91), or had specific IgE to cat (OR, 0.57; 95% CI, 0.39-0.82) at baseline. Adults who already had pets usually continued keeping the same type of pet, except that the presence of 3 or more asthma symptoms was associated with less subsequent dog keeping (OR, 0.69; 95% CI, 0.53-0.89). Pet removal between surveys to reduce allergen was reported by 4.7%., Conclusion: Selective avoidance subsequent to asthma or allergy was observed for childhood cat keeping and adult cat acquisition. Avoidance would produce an apparent protective effect of cats on childhood asthma (large OR, 0.83). Avoidance was generally not observed for dogs or birds., Clinical Implications: A part of the protective effects of childhood cats on asthma and allergy can be attributed to selective avoidance.

Background: The natural history of asthma severity is poorly known., Objective: To investigate prognostic factors of asthma severity., Methods: All current patients with asthma identified in 1991 to 1993 in the European Community Respiratory Health Survey were followed up, and their severity was assessed in 2002 by using the Global Initiative for Asthma categorization (n = 856). Asthma severity (remittent, intermittent, mild, moderate, severe) was related to potential determinants evaluated at baseline and during the follow-up by a multinomial logistic model, using the intermittent group as the reference category for relative risk ratios (RRRs)., Results: Asthma severity measured at baseline was a determinant of a patient's severity at the end of the follow-up. At baseline, severe persistent had a poorer FEV1% predicted, a poorer symptom control, higher IgE levels (RRR, 2.06; 95% CI, 1.38-3.06), and a higher prevalence of chronic cough/mucus hypersecretion (RRR, 4.90; 95% CI, 2.18-11.02) than patients with intermittent asthma. Moderate persistent showed the same prognostic factors as severe persistent, even if the associations were weaker. Mild persistent had a distribution of prognostic factors that was similar to patients with intermittent asthma, although the former showed a poorer symptom control than the latter. Remission mainly occurred in patients with less severe asthma and was negatively associated with a change in body mass index (RRR, 0.86; 95% CI, 0.75-0.97). Allergic rhinitis, smoking, and respiratory infections in childhood were not associated with asthma severity., Conclusion: Patients with moderate and severe persistent asthma are characterized by early deterioration of lung function. High IgE levels and persistent cough/mucus hypersecretion are strong markers of moderate/severe asthma, which seems to be a different phenotype from mild persistent or intermittent asthma., Clinical Implications: Our results suggest that the evolution of asthma severity is to a large extent predictable.

Background: Cross-sectional studies show that the prevalence of IgE sensitization is lower in older age groups than younger age groups. This could reflect either a decrease in sensitization with aging or a higher prevalence of sensitization in more recent birth cohorts., Objective: To assess change in IgE sensitization and mean total IgE in young adults as they age., Methods: Serum specific IgE to common allergens and total IgE were measured on 2 occasions about 9 years apart in 6371 young adults living in 28 centers, mainly in Western Europe, who took part in the European Community Respiratory Health Survey II. Outcomes were analyzed by using generalized estimating equations, and adjustments were made for differences between laboratory measures on the 2 occasions., Results: Overall, there was no net change in the prevalence of sensitization to at least 1 of house dust mite, grass, or cat (net change per 10 years of follow-up, -0.1%; 95% CI, -1.7% to 1.5%), although there was a fall in mean total IgE (ratio of geometric mean total IgE, 0.86; 95% CI, 0.79 to 0.93). There was evidence that sensitization to at least 1 allergen was higher in more recent cohorts, and this was largely explained by a higher prevalence of sensitization to grass., Conclusion: The disease burden associated with IgE sensitization in adults, and particularly with IgE sensitization to grass, is likely to continue to increase for some time despite current evidence that the increase in allergy seen in children may have ceased.

Background: Knowledge of the effects of early environmental and congenital factors on the natural history of asthma may provide important clues to the pathogenesis of asthma., Objective: We assessed associations between potential, early determinants and the incidence and remission of asthma throughout life, and tested whether the strength and direction of these associations varied in childhood, adolescence, and adulthood., Methods: The data pertaining to the individual asthma history of 18,156 subjects, age 0 to 44 years, who attended the clinical stage of the European Community Respiratory Health Survey were analyzed retrospectively by life-event methods. Onset of asthma was defined as age at the first attack, and asthmatic patients were considered to be in remission if they had not been under treatment or had an attack of asthma in the past 24 months. Onset and remission were evaluated in 3 time windows: <10, 10 to 20, and > or =20 years of age. The associations of asthma with early determinants were estimated by hazard ratios (HRs)., Results: A family history of asthma or allergy was associated with a higher risk of developing asthma (HR, 1.89; 95% CI, 1.67-2.13) and a lower chance of remission (HR, 0.79; 95% CI, 0.64-0.99) throughout life. No matter what one's genetic predisposition was, early, acute respiratory infections were associated with an increased lifelong risk of asthma onset (pooled HR, 3.19; 95% CI, 2.75-3.69), whereas early contact with older children, which is a marker of prolonged, intermittent exposure to infectious agents, conferred permanent protection against asthma (HR, 0.84; 95% CI, 0.74-0.96) and increased the chance of remission in childhood asthma (HR, 1.50; 95% CI, 1.10-2.04). Pet ownership had a protective effect only in childhood (HR, 0.78; 95% CI, 0.74-0.96), whereas maternal smoking did not show a significant association with asthma. Female sex was negatively associated with the onset of asthma in childhood (HR, 0.62; 95% CI, 0.52-0.75) and positively in adulthood (HR, 2.01; 95% CI, 1.61-2.51). The pattern of associations was similar in sensitized (positive assay to specific IgE) and nonsensitized asthmatic patients., Conclusion: Genetic predisposition and exposure to infectious agents are major early determinants that influence a subsequent history of asthma. The length and type of exposure to infectious agents seem able either to promote or to suppress an anti-inflammatory process, unrelated to IgE, which can partially interfere with an acquired predisposition for asthma.