title: Environments For Healthy Living (EFHL) Griffith birth cohort study: characteristics of sample and profile of antenatal exposures.
abstract: BACKGROUND
  The Environments for Healthy Living (EFHL) study is a repeated sample, longitudinal birth cohort in South East Queensland, Australia. We describe the sample characteristics and profile of maternal, household, and antenatal exposures. Variation and data stability over recruitment years were examined.
  
  
  METHODS
  Four months each year from 2006, pregnant women were recruited to EFHL at routine antenatal visits on or after 24 weeks gestation, from three public maternity hospitals. Participating mothers completed a baseline questionnaire on individual, familial, social and community exposure factors. Perinatal data were extracted from hospital birth records. Descriptive statistics and measures of association were calculated comparing the EFHL birth sample with regional and national reference populations. Data stability of antenatal exposure factors was assessed across five recruitment years (2006-2010 inclusive) using the Gamma statistic for ordinal data and chi-squared for nominal data.
  
  
  RESULTS
  Across five recruitment years 2,879 pregnant women were recruited which resulted in 2904 live births with 29 sets of twins. EFHL has a lower representation of early gestational babies, fewer still births and a lower percentage of low birth weight babies, when compared to regional data. The majority of women (65%) took a multivitamin supplement during pregnancy, 47% consumed alcohol, and 26% reported having smoked cigarettes. There were no differences in rates of a range of antenatal exposures across five years of recruitment, with the exception of increasing maternal pre-pregnancy weight (p=0.0349), decreasing rates of high maternal distress (p=0.0191) and decreasing alcohol consumption (p<0.0001).
  
  
  CONCLUSIONS
  The study sample is broadly representative of births in the region and almost all factors showed data stability over time. This study, with repeated sampling of birth cohorts over multiple years, has the potential to make important contributions to population health through evaluating longitudinal follow-up and within cohort temporal effects.
authors.affiliation: Injury Research Institute, Monash University, Melbourne, Victoria, Australia.
authors.forename: Cate M
authors.initials: CM
authors.lastname: Cameron
authors.forename: Paul A
authors.initials: PA
authors.lastname: Scuffham
authors.forename: Rania
authors.initials: R
authors.lastname: Shibl
authors.forename: Shukay
authors.initials: S
authors.lastname: Ng
authors.forename: Rani
authors.initials: R
authors.lastname: Scott
authors.forename: Anneliese
authors.initials: A
authors.lastname: Spinks
authors.forename: Gabor
authors.initials: G
authors.lastname: Mihala
authors.forename: Andrew
authors.initials: A
authors.lastname: Wilson
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Kendall
authors.forename: Neil
authors.initials: N
authors.lastname: Sipe
authors.forename: Roderick J
authors.initials: RJ
authors.lastname: McClure
mesh_terms: D000293:Adolescent; D000328:Adult; D003625:Data Collection / Q000639:trends*; D004781:Environmental Exposure; D005191:Family Characteristics; D005260:Female; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011247:Pregnancy; D037841:Pregnant People / Q000523:psychology*; D011297:Prenatal Exposure Delayed Effects; D011793:Queensland; D012307:Risk Factors; D012931:Social Environment; D011795:Surveys and Questionnaires; D055815:Young Adult