title: Predictive factors for age at menopause in Caucasian females.
abstract: OBJECTIVE
  Early onset of menopause results in the premature exposure to low estrogen levels and is associated with a number of postmenopausal health problems and higher risk of mortality. The aim of this study was to determine genetic and environmental factors associated with age at natural and surgical menopause.
  
  
  METHODS
  Multiple regression analysis using a sample of Caucasians composed of 154 females with surgical and 248 with natural menopause.
  
  
  RESULTS
  Breastfeeding is a significant predictor of earlier natural menopause (P<0.05). Use of oral contraceptives and smoking were not significantly associated with age at menopause. Females who did not have history of pregnancies are at significantly higher risk (P<0.001) of getting early surgical menopause than those who did. We also tested the association of seven single nucleotide polymorphisms (SNPs) of the estrogen receptor alpha (ER-alpha) gene with age at menopause. No association was observed with age at menopause but the PvuII p allele was overrepresented in women with surgical menopause and associated with menopause per se (P=0.029; OR=1.8, 95% CI=1.1-3.0).
  
  
  CONCLUSIONS
  Breastfeeding and alcohol consumption are significantly associated with earlier natural menopause. No significant effects of the ER-alpha genotypes were observed on the age of menopause. Given the important role of the ER-alpha in estrogen signaling, which directly influences the menopausal process, further studies are required to better define the relationship between this gene and age at menopause.
authors.affiliation: Department of Biological Sciences, Kent State University, Kent, OH 44242-0001, USA.
authors.forename: Volodymyr
authors.initials: V
authors.lastname: Dvornyk
authors.forename: Ji-Rong
authors.initials: JR
authors.lastname: Long
authors.forename: Peng-Yuan
authors.initials: PY
authors.lastname: Liu
authors.forename: Lan-Juan
authors.initials: LJ
authors.lastname: Zhao
authors.forename: Hui
authors.initials: H
authors.lastname: Shen
authors.forename: Robert R
authors.initials: RR
authors.lastname: Recker
authors.forename: Hong-Wen
authors.initials: HW
authors.lastname: Deng
mesh_terms: D017668:Age of Onset; D000428:Alcohol Drinking / Q000453:epidemiology; D001942:Breast Feeding / Q000453:epidemiology; D015984:Causality; D047628:Estrogen Receptor alpha / Q000235:genetics; D005260:Female; D006801:Humans; D008593:Menopause; D008875:Middle Aged; D010298:Parity; D020641:Polymorphism, Single Nucleotide; D011247:Pregnancy; D012907:Smoking / Q000453:epidemiology; D014481:United States / Q000453:epidemiology; D044465:White People
chemical_list: D047628:Estrogen Receptor alpha