title: The Tokyo Twin Cohort Project: overview and initial findings.
abstract: The Tokyo Twin Cohort Project (ToTCoP) is a large-scale longitudinal study of 5 years based on 1619 pairs of infant twins reared together. The purpose of the study is to construct a population-based twin registry in Japan and to investigate human growth and development and twin themselves. It covers behavioral, neurological, physical and environmental variables measured by questionnaire, home visiting and brain imaging technology. The full registry contains over 47,000 multiple births collected from the Basic Resident Register, and the targeted population is 3070 probable twins of 0 to 2 years old. Preliminary analysis of the entry questionnaire data showed no serious sampling biases. Descriptive statistics of parental characteristics (parental age, gestation age, parity and placentation, maternal weight, parenting stress) and children's characteristics (body size at birth, 4 and 10 months of age, milk consumption, and sleeping and social behavior) and their correlations, genetic and environmental contributions and correlations are reported.
authors.affiliation: Faculty of Letters, Keio University, Minato-ku, Tokyo, Japan. juko@msa.biglobe.ne.jp
authors.forename: Juko
authors.initials: J
authors.lastname: Ando
authors.forename: Koichi
authors.initials: K
authors.lastname: Nonaka
authors.forename: Koken
authors.initials: K
authors.lastname: Ozaki
authors.forename: Naho
authors.initials: N
authors.lastname: Sato
authors.forename: Keiko K
authors.initials: KK
authors.lastname: Fujisawa
authors.forename: Kunitake
authors.initials: K
authors.lastname: Suzuki
authors.forename: Shinji
authors.initials: S
authors.lastname: Yamagata
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Ryoko
authors.initials: R
authors.lastname: Nakajima
authors.forename: Noriko
authors.initials: N
authors.lastname: Kato
authors.forename: Syuichi
authors.initials: S
authors.lastname: Ooki
mesh_terms: D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D018579:Patient Selection; D010865:Pilot Projects; D012042:Registries; D014041:Tokyo; D018433:Twin Studies as Topic / Q000706:statistics & numerical data; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic