Disparate geographic prevalences of asthma, allergic rhinoconjunctivitis and atopic eczema among adolescents in five Canadian cities

Abstract

To assess concordance of prevalence rates of asthma, allergic rhinoconjunctivitis and atopic eczema symptoms among adolescents in five Canadian cities. The International Study of Asthma and Allergies in Childhood Phase 3 written questionnaires were answered by 8334 adolescents aged 13 to 14 in Vancouver, Saskatoon, Winnipeg, Hamilton and Halifax, Canada. Prevalence rates of current symptoms ranged from 13.7-33.0% for wheezing, 14.6-22.6% for allergic rhinoconjunctivitis and 8.2-10.4% for atopic eczema. Using Hamilton as reference, the prevalence of wheezing was significantly higher in Halifax (OR = 1.58; 95% CI 1.36-1.84) and Saskatoon (1.27; 1.07-1.50) and significantly lower in Vancouver (0.51; 0.44-0.59). In contrast, allergic rhinoconjunctivitis was significantly more prevalent in Winnipeg (1.39; 1.16-1.68) and Halifax (1.36; 1.14-1.61) and trended lower in Saskatoon (0.81; 0.66-1.00). Atopic eczema was significantly more prevalent in Winnipeg (1.31; 1.01-1.69) and Vancouver (1.28; 1.04-1.58). Multivariable logistic regression analyses showed the region of residence, being born in Canada, recent use of acetaminophen and heavy exposure to traffic exhaust were significantly associated with all three allergic conditions, while obesity and having two or more smokers at home was only associated with increased risk for wheezing. Chinese ethnicity decreased that risk. Among five Canadian centres, the highest prevalence rates of allergic rhinoconjunctivitis or atopic eczema were not observed in the same regions as the highest prevalence rates of wheezing. This disparity in regional variations in the prevalence rates suggests dissimilar risk factors for the development or expression of wheezing (asthma), allergic rhinoconjunctivitis and atopic eczema.

Obesity - A Promoter of Allergy?

“…Studies investigating overweight and obese children found that obesity increases the prevalence of wheezing and respiratory symptoms in subjects with a higher BMI compared to normal-weight subjects [12,13,14,15,16]. One study showed that, up to the age of eight, the risk for wheezing rises steadily with increasing BMI [12].…”

“…An increased BMI even has a dose-response effect on the risk of developing BA (table 1) [12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27]. Other obesity parameters, such as waist circumference, body fat percentage (%BF) or the waist-to-hip ratio, were also associated with an increased prevalence of BA [20,27,28,29].…”

Serum Leptin Level among School Children with Atopic Dermatitis

“…Three studies, including a UK cohort study and a substantial worldwide series of cross-sectional surveys based on the ISAAC Phase Three data set, found an association with obesity, while no association was detected in a number of other cross-sectional studies [30][31][32][33][34][35]. It remains unclear whether the positive associations seen are causal, for instance due to inflammation mediated by adipokines such as leptin, or related to dietary factors, which could facilitate AD through oxidative stress pathways are related to increased obesity and AD [4].…”

The Role of Environmental Control Measures in Asthmatic Children Who are Sensitized to House Dust Mites

“…Ev tozu akarlarına sıklıkla ılıman ve rutubetli bölgelerde rastlanır (12,15). Ev tozu akarlarıyla karşılaşmada sıcaklık ve nem oranı önemli rol oynar.…”