title: Factors influencing menarcheal age: results from the cohort of tehran lipid and glucose study.
abstract: BACKGROUND
  Menarche is considered as a milestone in the women's reproductive life. Most existing studies on factors influencing menarcheal age had cross-sectional designs and their finding were controversial.
  
  
  OBJECTIVE
  We aimed to determine some factors affecting the age at menarche in a cohort study with an average of ten-year follow-up; the study was conducted within the framework of Tehran Lipid and Glucose Study (TLGS).
  
  
  METHODS
  For the purpose of the present study, we recruited all the females aged 12 to 18 years participated in TLGS whose menarche had not begun at the initiation of the study, but occurred during their follow-up. The effect of premenarcheal status of various factors including socioeconomic and anthropometric parameters, physical activity, energy expenditure, and exposure to tobacco smoke on menarcheal age was explored.
  
  
  RESULTS
  The mean of age at menarche was 13.06 ± 1.24 years. There were significant statistical associations between age of the participants' mothers at menarche (r = 0.66, P < 0.001), maternal education (r = -0.04, P = 0.002), and body mass index (BMI) before menarcheal (r = 0.25, P = 0.027) with age at menarche. There was no significant correlation between age at menarche, with either of maternal employment, premenarcheal physical activity, energy expenditure, and passive smoking.
  
  
  CONCLUSIONS
  Among various factor influencing menarcheal age, premenarcheal BMI is modifiable, and considering its significance, could prevent early or late menarches.
authors.affiliation: Reproductive Endocrinology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Fahimeh
authors.initials: F
authors.lastname: Ramezani Tehrani
authors.affiliation: Obesity Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Parvin
authors.initials: P
authors.lastname: Mirmiran
authors.affiliation: Reproductive Endocrinology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Roya
authors.initials: R
authors.lastname: Gholami
authors.affiliation: Obesity Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Nazanin
authors.initials: N
authors.lastname: Moslehi
authors.affiliation: Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Feriedon
authors.initials: F
authors.lastname: Azizi
keywords: Body Mass Index; Longitudinal Studies; Maternal Educational Status.; Menarche