title: Childhood intermittent and persistent rhinitis prevalence and climate and vegetation: a global ecologic analysis.
abstract: BACKGROUND
  The effect of climate change and its effects on vegetation growth, and consequently on rhinitis, are uncertain.
  
  
  OBJECTIVE
  To examine between- and within-country associations of climate measures and the normalized difference vegetation index with intermittent and persistent rhinitis symptoms in a global context.
  
  
  METHODS
  Questionnaire data from 6- to 7-year-olds and 13- to 14-year-olds were collected in phase 3 of the International Study of Asthma and Allergies in Childhood. Associations of intermittent (>1 symptom report but not for 2 consecutive months) and persistent (symptoms for ≥2 consecutive months) rhinitis symptom prevalences with temperature, precipitation, vapor pressure, and the normalized difference vegetation index were assessed in linear mixed-effects regression models adjusted for gross national income and population density. The mean difference in prevalence per 100 children (with 95% confidence intervals [CIs]) per interquartile range increase of exposure is reported.
  
  
  RESULTS
  The country-level intermittent symptom prevalence was associated with several country-level climatic measures, including the country-level mean monthly temperature (6.09 °C; 95% CI, 2.06-10.11°C per 10.4 °C), precipitation (3.10 mm; 95% CI, 0.46-5.73 mm; per 67.0 mm), and vapor pressure (6.21 hPa; 95% CI, 2.17-10.24 hPa; per 10.4 hPa) among 13- to 14-year-olds (222 center in 94 countries). The center-level persistent symptom prevalence was positively associated with several center-level climatic measures. Associations with climate were also found for the 6- to 7-year-olds (132 center in 57 countries).
  
  
  CONCLUSIONS
  Several between- and within-country spatial associations between climatic factors and intermittent and persistent rhinitis symptom prevalences were observed. These results provide suggestive evidence that climate (and future changes in climate) may influence rhinitis symptom prevalence.
authors: School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada; Institute of Epidemiology I, Helmholtz Zentrum München - German Research Centre for Environmental Health, Neuherberg, Germany. Electronic address: efuertes@interchange.ubc.ca.
authors: Elaine
authors: E
authors: Fuertes
authors: MRC-PHE Centre for Environment and Health, St Georges, University of London, London, United Kingdom.
authors: Barbara K
authors: BK
authors: Butland
authors: MRC-PHE Centre for Environment and Health, St Georges, University of London, London, United Kingdom; MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom.
authors: H
authors: H
authors: Ross Anderson
authors: School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada; Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors: Chris
authors: C
authors: Carlsten
authors: MRC-PHE Centre for Environment and Health, St Georges, University of London, London, United Kingdom.
authors: David P
authors: DP
authors: Strachan
authors: School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada; Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors: Michael
authors: M
authors: Brauer
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000453:epidemiology; D002648:Child; D057231:Climate Change; D004485:Eczema / Q000453:epidemiology; D006801:Humans; D010944:Plants / Q000276:immunology*; D012221:Rhinitis, Allergic, Perennial / Q000453:epidemiology* / Q000276:immunology; D006255:Rhinitis, Allergic, Seasonal / Q000453:epidemiology* / Q000276:immunology; D011795:Surveys and Questionnaires