Korean J Epidemiol.  1998 Jun;20(1):70-81.

Reproductive Factors Related to Serum Estrogen, Progesterone, and Sex Hormone Binding Globulin in Postmenopausal Women in Korea

• Kim CH
• Park SK
• Kim H
• Ha MN
• Shin HR
• Lee BO
• Kim DS
• Kang DH
• Yoo KY

Abstract

The etiology of breast cancer is not yet clear. Several epidemiologic studies have supported the concepts that endogenous female sex hormones, i.e., estrogen and progesterone, may play a central role in the development of breast cancer. Female reproductive factors such as menstruation, pregnancy, and breast feeding are well-known risk factors of breast cancer. There have been many suggestions that all these factors are midiated by female sex hormeones. However, only a few studies have evaluated the relationship between the reproductive factors and endogenous female sex hormones. This study was designed to evaluate the relationship between the reproductive factors and endogenous female sex hormones in Korean women. We analyzed the relationship between reproductive factors and female sex hormones in 153 premenopausal women 153 postmenopausal women who participated in a community health promotion program in Haman County, Korea. The questionnaires about reproductive factors were completed by personal interview. Serum level of total estradiol(E2), progesterone(:g), and sex hormone binding globulin(SHBG) were measured by radioimmunoassay. There was no significant correlation between age at menarche and E2 in both premenopausal and postmenopausal groups. In postmenopausal subjects, E2 level increased significantly with the age at menopause increasing(r=0.25, p=0.009), adjusting for the potential confounding effect of both age and body mass index. There was a positive correlation between E2 and the intervals between age at menarche and age at menopause(r=0.25, p=0.009). Moreover, the serum level of SHBG was significantly correlated with total months of breast feeding(r=0.19, p=0.048), as well as with age at first fullterm pregnancy(r=-0.24, p=0.01). However, Pg was correlated with none of reproductive factors in both groups. This study observed that female reproductive factors, e.g., age at menopause, breast feeding, age at first fullterm pregnancy, were correlated with serum female hormones, particularly E2 and SHBG. The results provide an evidence that the relationship between the reproductive factors and breast cancer risk may be mediated, at least in part, through serum female hormones, especially estradiol in Korean women.

Keyword

Age at menarche; Age at menopause; Estradiol; Fullterm pregnancy; Progesterone; Sex hormone binding globulin

MeSH Terms

Body Mass Index
Breast
Breast Feeding
Breast Neoplasms
Epidemiologic Studies
Estradiol
Estrogens*
Female
Gonadal Steroid Hormones
Health Promotion
Humans
Korea*
Menarche
Menopause
Menstruation
Pregnancy
Progesterone*
Radioimmunoassay
Risk Factors
Sex Hormone-Binding Globulin*
Surveys and Questionnaires
Estradiol
Estrogens
Gonadal Steroid Hormones
Progesterone
Sex Hormone-Binding Globulin