Menopause age and affecting factors in Tehran Lipid and Glucose Study (TLGS)

Background: Menopause is considered as the cessation of menstrual cycles and reproductive potential. Although the age at menopause is known to affect the development of diseases however, little information on factors affecting the age at menopause is available. Objective: The aim of the present study was to determine the menopausal age and affecting factors among the women investigated during the Tehran Lipid and Glucose Study (TLGS). Methods: There were 1114 women aged 39-70 in the TLGS who developed menopause naturally. All women were interviewed by a trained interviewer using a standard questionnaire containing questions associated with socio-demographic and reproductive status while a general physical exam was also performed. Menopause was defined according to the WHO classification as a condition of absence of spontaneous menstrual bleeding for more than 12 months, for which no other pathologic or physiologic cause could be determined. Age at menopause (AMP) was calculated for each individual based on report of the last menstrual cycle. Data were analyzed by ordinal regression and ANOVA using SPSS version15. Findings: The mean age at menopause was 49.6±4.5. The age at menopause was affected by smoking, menarcheal age, and the number of birth i.e., an increase in menarcheal age and the number of birth caused increased menopausal age while the previous history of smoking resulted in decreased age at menopause. Conclusion: It seems that smoking, reproductive status, and the menarcheal age to be among the factors influencing the menopausal age in Iranian population.