title: [Enrolment and follow-up of a birth cohort in Rome].
abstract: OBJECTIVE
  Longitudinal studies on cohorts of babies enrolled at birth are ongoing in Europe. On the basis of these experiences, a birth cohort study should be implemented in Italy at a national level. A pilot study is ongoing in Rome, from which we report data on adherence at recruitment and follow-up.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  the birth cohort was enrolled between June 2003 and October 2004, in two hospital ofRome in the district ofthe Local Health Unit RME.
  
  
  METHODS
  we enrolled children of women older than 18 years, Italian citizens and residents in the Local Health Unit RME.
  
  
  METHODS
  Baseline characteristics of enrolled women were compared with those of refusals, and characteristics of children with a complete follow-up with those lost at follow-up. Prevalence Rate ratio (PR) and the relative 95% confidence interval were calculated.
  
  
  RESULTS
  The cohort consisted of 704 women (54% of the contacted) and 719 children. A low level of instruction (PR 2.84), and a caesarean delivery (OR 1.41) were significantly associated with the refusal. After the enrolment 25 children were lost, 117 were partially followed-up and 577 had a complete follow-up until the 15 month visit. Mothers of children lost at follow-up were less instructed (PR 1.69) and smoked during pregnancy (PR 1.57).
  
  
  CONCLUSIONS
  During the enrolment and the follow-up of a birth cohort greater efforts must be done to avoid selection for the socioeconomic level of the family. Keeping a high response rate to follow-up is the only way to ensure a good level of internal validity.
authors.affiliation: Dipartimento di epidemiologia, ASL Roma E, Roma. porta@asplazio.it
authors.forename: Daniela
authors.initials: D
authors.lastname: Porta
authors.forename: Francesco
authors.initials: F
authors.lastname: Forastiere
authors.forename: Domenico
authors.initials: D
authors.lastname: Di Lallo
authors.forename: Carlo A
authors.initials: CA
authors.lastname: Perucci
mesh_terms: D000328:Adult; D002585:Cesarean Section; D015331:Cohort Studies; D016001:Confidence Intervals; D004493:Education; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007407:Interviews as Topic; D009035:Mothers; D010865:Pilot Projects; D011247:Pregnancy; D011446:Prospective Studies; D012384:Rome; D012907:Smoking / Q000453:epidemiology; D012959:Socioeconomic Factors