title: Age at menarche in a Chuvashian rural population.
abstract: OBJECTIVE
  The secular trend and familial influences on age at menarche among a rural Chuvashian population was examined in a cross-sectional community-based study.
  
  
  METHODS
  The cohort included 617 females aged 18-80 years, with age at menarche ranging from 10 to 24 years (mean 15.4 +/- 2.1). Statistical analyses included simple linear regression, maximum likelihood estimation and a whiskers plot.
  
  
  RESULTS
  Women born during the second through the fourth decade of the 20th century showed increasing mean values of age at menarche from 15.4 (second decade) up to 16.5 (fourth decade). Women born after the fourth decade showed a decrease in mean values from 15.5 (fifth decade) to 13.0 (ninth decade). The highest peak of age at menarche was in women born in 1932. Significant familial correlations were observed between adjusted to year of birth age at menarche in mothers and daughters r = 0.195, p<0.01 and sisters and sisters r = 0.404, p<0.01.
  
  
  CONCLUSIONS
  Our study demonstrated the certain secular trends of age at menarche in Chuvashian women who matured after World War II. Periods of socio-economic disasters such as war and famine disrupt the secular trend. Our findings also confirm the hypothesis of significant familial influences on menarcheal age.
authors.affiliation: Department of Physical Therapy, The Stanley Steyer School of Health Professions, Tel Aviv 69978, Israel.
authors.forename: Leonid
authors.initials: L
authors.lastname: Kalichman
authors.forename: Ida
authors.initials: I
authors.lastname: Malkin
authors.forename: Gregory
authors.initials: G
authors.lastname: Livshits
authors.forename: Eugene
authors.initials: E
authors.lastname: Kobyliansky
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008572:Menarche / Q000208:ethnology*; D008875:Middle Aged; D012423:Rural Health; D012424:Rural Population; D012426:Russia