Time trends of co-existing atopic conditions in Singapore school children: prevalence and related factors.

Atopic diseases are known to co-exist and are interrelated. Their co-existence in a patient increases disease burden and morbidity. We sought to study the prevalence of co-existing atopic conditions over time and its associated risk factors among Singapore children. Data was collected from two respective The International Study of Asthma and Allergies in Childhood surveys conducted in 1994 and 2001. Data on asthma, rhinitis and eczema were obtained from the responses to questions about wheezing, exercise-induced wheezing, nocturnal cough, rhinitis symptoms, rash, and diagnoses of asthma, rhinitis and eczema in the last 12 months. Data on demographic and known risk factors were also obtained. The prevalence of children who have had more than one atopic disorder increased significantly from 6.0% in 1994 to 10.2% in 2001 (p < 0.001). Parental history of atopic disease, maternal educational level, male gender and smoke exposure were significantly associated with co-existent atopic symptoms in the child. Among Singapore schoolchildren, there was a significant prevalence of co-existent atopic disease and this prevalence was rising. The influences of both genetic and environmental factors were likely to have contributed to these observations.