title: Time-related trends of age at menopause and reproductive period of women in a Chuvashian rural population.
abstract: OBJECTIVE
  The objective of this study was to examine in an observational, cross-sectional, community-based study the secular trend of age at menopause among women in a rural Chuvashian population and to identify factors associated with age at menopause.
  
  
  METHODS
  The sample included 316 postmenopausal women born between 1920 and 1950 with mean age at menopause of 48.47 +/- 4.63 (34-58) years. Statistical analyses included simple and multiple linear regression and "whiskers" plots.
  
  
  RESULTS
  Significant association was found between year of birth and age at menopause (beta = 0.194, P < 0.001) and reproduction period (P = 0.193, P < 0.001). Mean values of age at menopause increased from 47.0 years (born during 1920-1925) to maximal values of 49.7 years (born during 1940-1945) and 49.3 years (born during 1945-1950). Mean values of their reproductive period increased from 30.7 (born during 1920-1925) to maximal values of 34.1 (born during 1940-1945) and to 33.7 (born during 1945-1950). Multiple linear regression analysis demonstrated that year of birth was the only statistically significant (P = 0.19, P < 0.01) predictor of age at menopause. Age at menarche can also be a possible predictor of age at menopause (beta = -0.12, P = 0.04).
  
  
  CONCLUSIONS
  The study confirmed certain secular trends of age at menopause and reproductive periods in Chuvashian women. The authors also observed a negative association between age at menarche and age at menopause. The number of children and medical abortions as well as body mass index showed no association with age at menopause.
authors.affiliation: Department of Physical Therapy, Stanley Steyer School of Health Professions, Tel Aviv University, Tel Aviv, Israel. anatom14@post.tau.ac.il
authors.forename: Leonid
authors.initials: L
authors.lastname: Kalichman
authors.forename: Ida
authors.initials: I
authors.lastname: Malkin
authors.forename: Eugene
authors.initials: E
authors.lastname: Kobyliansky
mesh_terms: D000328:Adult; D017677:Age Distribution; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008572:Menarche; D008593:Menopause; D008875:Middle Aged; D012424:Rural Population; D012426:Russia