title: Dry night cough as a marker of allergy in preschool children: the PARIS birth cohort.
abstract: BACKGROUND
  Early detection of children at risk for developing allergy is an important challenge. Our first analyses in infants from the Pollution and Asthma Risk: an Infant Study (PARIS) birth cohort suggested that dry night cough was associated with parental-reported allergic disorders. The aim of the present study was to refine this finding by investigating the time course of dry night cough from birth to age 4 yr in relation to blood markers of atopy and allergic morbidity.
  
  
  METHODS
  Health outcomes were regularly assessed by parental self-administered questionnaires. Blood markers of atopy were measured at age 18 months. Children with similar patterns of dry night cough over the first 4 yr of life were grouped together using k-means clustering. Associations with atopy/allergy were studied using multinomial logistic regression.
  
  
  RESULTS
  Three trajectories of dry night cough were identified in 1869 children. Besides the never/infrequent pattern (72.4%), the transient pattern (8.8%) was composed of children who coughed in the first year and recovered by age 4 yr, while the rising pattern (18.8%) included all symptomatic children at age 4 yr, whether they were persistent or late coughers. Compared with the never/infrequent pattern, the rising pattern was significantly associated with elevated total immunoglobulin E (IgE) level (odds ratio [OR] = 1.70, 95% confidence interval [CI] = 1.21-2.39) and inhalant allergens sensitization (OR = 2.66, 95% CI = 1.26-5.61) at age 18 months, and with doctor-diagnosed allergic diseases over the first 4 yr such as hay fever (OR = 2.52, 95% CI = 1.49-4.26) and eczema (OR = 1.29, 95% CI = 1.00-1.66).
  
  
  CONCLUSIONS
  This study provides evidence that persistent/late dry night cough may indicate allergy in preschool children.
authors: Univ Paris Descartes, Sorbonne Paris Cité, EA 4064, Laboratoire Santé Publique et Environnement, Paris, France.
authors: Fanny
authors: F
authors: Rancière
authors: Lydia
authors: L
authors: Nikasinovic
authors: Isabelle
authors: I
authors: Momas
mesh_terms: D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D002675:Child, Preschool; D002940:Circadian Rhythm; D016000:Cluster Analysis; D003371:Cough / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D010297:Paris / Q000453:epidemiology; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D013997:Time Factors
chemical_list: D015415:Biomarkers; D007073:Immunoglobulin E