Sensitization to common food allergens is a risk factor for asthma in young Chinese children in Hong Kong

Sensitization to aeroallergens is a major risk factor for asthma. Although patients frequently consider food ingestion as an asthma trigger, the relationship between serum food-specific IgE antibodies and childhood asthma in China remains unclear. We therefore conducted a case-control study on asthmatic children attending a university hospital-based outpatient clinic to investigate their pattern of food sensitization. Asthmatic patients underwent spirometric assessment, and peripheral blood was collected for serum-specific IgE antibodies to common food and inhalant allergens. Two hundred and thirty-one asthmatics (aged 9.3+/-4.3 years) and 79 age- and sex-matched controls were enrolled. The serum logarithmic total IgE concentrations in patients and controls were 2.49 and 1.92, respectively (p < 0.0001). Subjects with increased serum total IgE level were significantly more likely to have food sensitization than those with normal values (33% vs. 16%; p = 0.001). Twenty-nine (52%) of 56 asthmatics younger than 6 years old and seven (27%) of 26 age-matched controls had food-specific IgE in their sera (p = 0.035). Asthmatics with food-specific IgE also used more doses of as-needed bronchodilator weekly (p = 0.005). Nonetheless, no association was found between asthma diagnosis and sensitization to individual food allergens. Significant food sensitization, with food-specific IgE level above 95% predictive values for clinical food allergy as proposed by Sampson, was only found in two patients for peanut and three subjects for egg white. In conclusion, a significant association was found between asthma and the presence of food-specific IgE antibodies in young Chinese children. Significant sensitization to common foods is rare in this cohort.