There were 1828 students attending these four surveyed schools. The video and self-administrated questionnaires were obtained at the classroom. Among 1757 (96.1%) returned questionnaires, 12 of them were excluded for incomplete information associated with asthma and GERD. The characteristics of 1745 study subjects were summarized in Table 1. The proportions of Taiwan aborigines, Han Chinese, and bi-ethnicity were 38%, 43%, and 17%, respectively. The prevalence rates of overweight and obesity were 8.8% and 10.9%, respectively. Approximately one sixth of the subjects had elevated waist circumferences.
Prevalence Rates of Symptoms of GERD, Asthma, and Food Allergy
Table 2 displayed the prevalence rates of symptoms of GERD, asthma, and food allergy. The cumulative and 3-month prevalence rates of GERD symptoms were 20.5% and 8.9%, respectively. Among adolescents who had experienced GERD symptoms, less than 45% of them had symptoms occurred during the recent 3 months. Four hundred and seventy-seven (27.3%) students had ever-experienced asthma, and approximately two third of them had asthmatic symptoms in the past year. The proportion of subjects who had at least one category of food-related allergic symptoms was 17%, and the most frequent symptom was skin rash or itching.
The prevalence rates of GERD symptoms in subjects of different characteristics were showed in Table 3. Female and grade 8 students had higher prevalence rates of GERD symptoms. As compared with aboriginal adolescents, the prevalence rates of GERD symptoms were significantly elevated for bi-ethnic adolescents. No significant difference in the prevalence was observed between aboriginal and Han Chinese ethnicities. The cumulative and 3-month prevalence rates of GERD symptoms of ever smokers were both significantly higher than those of nonsmokers (25.4% and 12.7% vs 18.0% and 7.0%, respectively; both P values < 0.001). There was no significant association between obesity and GERD symptoms.
The comparisons of prevalence rates of GERD symptoms according to asthmatic and food-related allergic symptoms were shown in Table 4. Subjects who had asthma attacks in the past year had the highest cumulative prevalence rates, followed by subjects who had asthma attacks more than 1 year before, and the least for subjects who never had asthma attack. Chi-square tests showed the differences in the cumulative and 3-month prevalence rates were both statistically significant (P < 0.0001). The cumulative prevalence rates of GERD symptoms for subjects who had food-related allergic symptoms were 1.6–2.6-fold higher than those who did not. The corresponding figures for the 3-month prevalence rates were 2.1–4.7-fold.
Multivariate Analyses of Factors Associated with GERD Symptoms
Because the prevalence rates of GERD symptoms in aboriginal and Han Chinese students were similar, we combined them into a new group "uni-ethnicity." Multivariate logistic regression analyses showed that the cumulative prevalences of GERD symptoms were significantly correlated with bi-ethnicities, cigarette smoking, and symptoms of asthma and food allergy (Table 5). As compared with subjects who never had asthmatic symptoms, the multivariate-adjusted odds ratios (ORs) of having GERD symptoms were 3.59 (95% CI: 2.69–4.82) and 2.43 (1.67–3.53) for subjects who had asthma attacks in the past year or more than 1 year before, respectively. The adjusted ORs for the presence of food-related allergic symptoms were 1.5–3.3-fold higher than those who were absent of.
Table 5 also showed that bi-ethnicities, cigarette smoking, and the presence of asthmatic and food-related allergic symptoms were all significantly correlated with 3-month prevalence of GERD symptoms. The multivariate-adjusted ORs for subjects who had asthma attacks in the past year (5.13; 95% CI: 3.47–7.58) or more than 1 year before (2.26; 95% CI: 1.28–3.93) were both significantly higher than that of subjects who never had asthmatic symptoms. The multivariate-adjusted ORs for subjects who had food-related allergic symptoms were 1.7–6.7-fold higher than those who did not have the corresponding allergic symptoms. As compared with uni-ethnic adolescents, the multivariate-adjusted OR for bi-ethnic subjects was 1.59 (1.03–2.45).
J Gastroenterol Hepatol. 2014;29(2):269-275. © 2014 Blackwell Publishing