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.
- Asthma risk
- exhaled nitric oxide
- developing country
- asthma epidemiology
- clinical epidemiology
- exhaled airway markers
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Funding The study was supported by the Johns Hopkins Center for Global Health (Principal Investigator NNH) and the Fogarty International Center, National Institutes of Health (NIH; grant R24 TW007988). WC was supported by a Clinician Scientist Award from the Johns Hopkins University, a K99/R00 Pathway to Independence Award (K99HL096955) from the National Heart, Lung and Blood Institute, NIH and by a contract (HHSN268200900033C) with the National Heart, Lung and Blood Institute, NIH. KCB was supported in part by the Mary Beryl Patch Turnbull Scholar Program. CLR was a Fogarty International Clinical Research Scholar during the time of the study and was further supported by Tufts University School of Medicine and by a pre-doctoral T35 Training Grant (T35AI065385) of the NIH. LMB was supported by a predoctoral T35 Training Grant (T35AI065385) of the NIH. Support for exposure measurements was provided by National Institute for Environmental Health Sciences grant numbers (ES015803). RAW was supported in part by the Dorney–Koppel Family Foundation. NNH, WC and PNB were also supported by an R01 grant from the National Institutes of Environmental Health Sciences (R01ES018845). Study sponsors played no role in the study design, data collection, data analysis, data interpretation or the decision to submit the article for publication. The opinions, results and conclusions reported in this paper are those of the authors and are independent from the funding sources. All authors had full access to all of the data (including statistical reports and tables) in the study and can take responsibility for the integrity of the data and the accuracy of the data analysis.
Competing interests None.
Ethics approval This study was conducted with the approval of the Institutional Review Boards of the Johns Hopkins Bloomberg School of Public Health in Baltimore, USA, and AB PRISMA in Lima, Peru.
Provenance and peer review Not commissioned; externally peer reviewed.
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