Effect of urbanisation on asthma, allergy and airways inflammation in a developing country setting

Abstract

Background Asthma is a growing public health problem in developing countries. However, few studies have studied the role of urbanisation in this phenomenon. It was hypothesised that children living in a peri-urban setting in Peru have higher rates of asthma and allergy than rural counterparts. Methods 1441 adolescents aged 13–15 years were enrolled from two settings: a peri-urban shanty town in Lima (n=725) and 23 rural villages in Tumbes (n=716). Participants filled in questionnaires on asthma and allergy symptoms, environmental exposures and sociodemographics, and underwent spirometry, and exhaled nitric oxide (eNO) and allergy skin testing. Indoor particulate matter (PM) concentrations were measured in 170 households. Results Lima adolescents had higher rates of lifetime wheezing (22% vs 10%), current asthma symptoms (12% vs 3%) and physician-diagnosed asthma (13% vs 2%; all p <0.001). Current rhinitis (23% vs 12%), eczema (12% vs 0.4%), atopy (56% vs 38%), personal history of cigarette smoking (7.4% vs 1.3%) and mean indoor PM (31 vs 13 μg/m3) were also higher in Lima (all p <0.001). The peri-urban environment of Lima was associated with a 2.6-fold greater odds (95% CI 1.3 to 5.3) of asthma in multivariable regression. Forced expiratory volumes were higher and FEV1/FVC (forced expiratory volume in 1 s/forced vital capacity) ratios were lower in Lima (all p <0.001). Higher eNO values in Lima (p <0.001) were attributable to higher rates of asthma and atopy. Conclusions Peri-urban adolescents had more asthma, atopy and airways inflammation and were exposed to more indoor pollution. The findings provide evidence of the risks posed to lung health by peri-urban environments in developing countries.

Pulmonary function tests in Egyptian schoolchildren in rural and urban areas

“…The Global Lung Function Initiative equations were used to calculate FEV1 predicted and FVC predicted and the results showed that these measures were all higher in Shibin El-Kom than Cairo. These findings confirm previous studies that reported differences in pulmonary function between urban and rural areas (8,19), which could indicate sub-clinical airway narrowing and slower pulmonary growth rate (3). The decrease in FVC and FEV1 was likely due to decrease in lung tissue elasticity and an increase in big airway resistance, although obstructions in small airways can also decrease FEV1 (20).…”

Effects of home environment and lifestyles on prevalence of atopic eczema among children in Wuhan area of China

“…Atopic eczema has also been shown to be an increasing problem in urban Nigeria [21]. The peri-urban environment of Lima was associated with 2.6-fold greater odds (95% CI: 1.3-5.3) of allergic disease [22]. In Wuhan, close proximity to a business zone, highway, or industrial area was a risk factor for eczema symptoms, with odds ratios of 1.4-2.8.…”

Role Of Exhaled Nitric Oxide As A Predictor Of Atopy

“…Scott et al [18] reported a positive correlation between FeNO and the number of positive skin prick tests in a cohort of asthmatics. Previous studies have also correlated aeroallergen sensitization with FeNO levels in atopic children [7,13,16,19,20]. These findings underscore the relevance of evaluating allergen sensitization status when FeNO is used as a biomarker in the diagnosis and monitoring of asthma [18].…”

“…For these reasons, FeNO has been recently recommended as a clinical endpoint for the characterization of study populations, in clinical trials and observational studies [10]. Recent studies, however, have reported high levels of FeNO even in well-controlled asthma [1,6,11], indicating that other factors may play a role in the determination of FeNO levels [12][13][14][15]. One potential factor that could explain variability in FeNO levels is atopic status.…”