title: Genetic and environmental influences on pubertal timing assessed by height growth.
abstract: Secular trends towards earlier puberty, possibly caused by new environmental triggers, provide a basis for periodic evaluation of the influence and interaction of genetic and environmental effects on pubertal timing. In such studies, a practical marker that reflects timing of puberty in both genders needs to be used. We investigated genetic and environmental influences on pubertal timing by using change in the relative height between early and late adolescence (HD:SDS, height difference in standard deviations) as a new marker of pubertal timing. HD:SDS correlated well with age at peak height velocity in a population of men and women with longitudinal growth data. In 2,309 twin girls and 1,828 twin boys, HD:SDS was calculated between height SDs at age 11.5 and 17.5, and 14.0 and 17.5 years, respectively. Quantitative genetic models for twin data were fitted to estimate the genetic contribution to HD:SDS. We also investigated whether the same genetic factors influenced individual differences between HD:SDS and development of secondary sex characteristics prospectively collected by pubertal development scale (PDS). Genetic effects contributed to 86 and 82% of the variance in HD:SDS in girls and boys, respectively, when using the same model including additive genetic and specific environmental factors. In girls, 30% and in boys, 49% of the genetic factors affecting PDS and HD:SDS were the same. Future comparison of the results of periodic evaluations allows estimation of possible changes in the effects of environment on timing of puberty. In such studies, HD:SDS can be used as a practical marker of pubertal timing.
authors.affiliation: Hospital for Children and Adolescents, Helsinki University Hospital, 00290 Helsinki, Finland. karoliina.wehkalampi@hus.fi
authors.forename: Karoliina
authors.initials: K
authors.lastname: Wehkalampi
authors.forename: Karri
authors.initials: K
authors.lastname: Silventoinen
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kaprio
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Dick
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Rose
authors.forename: Lea
authors.initials: L
authors.lastname: Pulkkinen
authors.forename: Leo
authors.initials: L
authors.lastname: Dunkel
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001827:Body Height / Q000235:genetics / Q000502:physiology; D002648:Child; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D008957:Models, Genetic; D015233:Models, Statistical; D011627:Puberty / Q000235:genetics*; D012016:Reference Values; D011795:Surveys and Questionnaires; D013997:Time Factors