title: The relationship between malocclusion and menarcheal age, and its secular trend for Korean women.
abstract: OBJECTIVE
  This study aimed to evaluate the mean age of menarche, its secular trend in Korean women, and the relationship between malocclusion and the rate of skeletal maturation, as defined by menarcheal age.
  
  
  METHODS
  We retrospectively collected data on menarcheal age from 931 Korean women born during 1961 - 1997. Subjects were divided by the malocclusion type and birth-year decade into 3 and 4 groups, respectively. The mean menarcheal age for each group was determined, and one-way ANOVA was performed for intergroup comparison (p = 0.05). Two-way ANOVA was also performed to compare all the 12 subgroups (p = 0.05).
  
  
  RESULTS
  The mean age of menarche was 12.82 years for Korean women born during 1961 - 1997. A distinct downward secular trend of menarcheal age was noticed (p < 0.05). For the birth-year decade 1961 - 1970, the Class III malocclusion group showed earlier onset of menarche than the other malocclusion groups (p < 0.05), but the other birth-year groups did not show any significant difference in the type of malocclusion (p > 0.05).
  
  
  CONCLUSIONS
  A positive secular trend towards earlier menarche exists among Korean women. Malocclusion does not show any significant relationship with the rate of skeletal maturation, as defined by menarcheal age.
authors.affiliation: Department of Orthodontics, Gangnam Severance Dental Hospital, College of Dentistry, Institute of Craniofacial Deformity, Yonsei University, Seoul, Korea.
authors.forename: Yoon Jeong
authors.initials: YJ
authors.lastname: Choi
authors.forename: Chooryung
authors.initials: C
authors.lastname: Chung
authors.forename: Kyung-Ho
authors.initials: KH
authors.lastname: Kim
keywords: Malocclusion; Menarche; Secular trend; Skeletal maturation