Premenopausal Hormone Concentrations in a Population of Women at Very Low Risk of Breast Cancer
Condition: Menopause; Normal Physiology
Study type: Observational

Summary: 
      Background:

        -  Incidence of breast cancer is very low in Mongolia (6.6/100,000), especially in rural
           areas. Over the past 15 years, there has been considerable economic growth in Mongolia,
           resulting in migration to urban centers such as the capital, Ulaanbaatar, from areas
           with nomadic or semi-nomadic lifestyles. This recent migration offers an opportunity to
           study the endocrine profiles of premenopausal women as they acculturate to a more
           Western lifestyle.

      Objectives:

        -  To obtain new data on premenopausal endocrine and growth factor concentrations to assess
           possible variations by migration status within Ulaanbaatar; that is, to compare women
           who have been living in Ulaanbaatar for the longest period of time with those who have
           recently moved to Ulaanbaatar.

        -  To compare data from Mongolia with data from the United States (and possibly China),
           where women are at higher risk of breast cancer.

      Eligibility:

        -  A sample of 375 premenopausal women will be drawn from a larger sample of mothers whose
           children are participating in a study conducted by Harvard Medical School. Only mothers
           of girls will be included in this cross-sectional study. Women ages 25 44 years who are
           not pregnant or breastfeeding are eligible.

      Design:

        -  A total of 30 ml (three 10 ml samples) of whole blood will be collected. Women will be
           asked to provide a spot urine sample. These samples will be sent periodically to the NCI
           biorespository during the course of the study for testing. A portion of a sample for
           each participant will be kept in Ulaanbaatar in case of problems in delivery to the
           United States.

        -  The following hormones will be evaluated: testosterone, androstenedione,
           dehydroepiandrosterone (DHEA), DHEA-sulfate, estrone, estradiol, estriol, progesterone,
           prolactin, placental lactogen, IGF-1 and IGFBP-3, VEGF, soluble endoglin, and possibly
           other angiogenic proteins.

        -  Socioeconomic status and medical and lifestyle information will be assessed by
           questionnaire, including ethnicity, occupation, education, and migration status (e.g.,
           whether she moved from a rural area and time since migration). Breast cancer risk
           factors such as age at first pregnancy, age at first menstruation, gravidity (total
           number of pregnancies), parity (total number of childbirths), smoking status, alcohol
           use, and dietary intake will also be determined. (These questionnaires will have been
           pilot tested and revised before the start of this study.) The Global Physical Activity
           Questionnaire, developed by the World Health Organization, will assess physical
           activity.

        -  Mean and median premenopausal hormone concentrations of previously collected blood
           samples from women in the United States who are at high breast cancer risk will be
           compared with the Mongolian samples. In addition, Chinese data will be compared if
           available.
    

Detailed description: 
      There are striking differences in breast cancer incidence rates between Asian and North
      American and Western European populations, but within Asia variation is also wide. Incidence
      in Mongolia is one of the lowest in the world (6.6/100,000) while China, its neighbor to the
      south, has about three times this rate (18.7/100,000). Furthermore, rates appear higher in
      urban than in rural areas in Mongolia. Over the last decade and a half Mongolia has
      experienced profound economic changes resulting in mass migration from a nomadic or
      semi-nomadic existence to a more western lifestyle in the capital city of Ulaanbaatar, and
      some back migration to rural areas. Together with the contrast in exposures between
      traditional and urban settings, migration presents the opportunity to study women as they
      acculturate to a more western lifestyle.

      We propose collecting blood and urine samples from premenopausal Mongolian women living in
      UlaanBaatar, the capital of Mongolia, to describe concentrations of several steroid hormones
      and growth factors that play a role in breast cancer development. The purpose of the study is
      to assess whether endocrine profile differs by degree of Western acculturation among those
      who have recently migrated to the capital. Subjects will be recruited among mothers of girls
      participating in a study of milk consumption and hormonal status presently being conducted by
      our colleagues at Harvard Medical School. In addition to the blood draw and urine collection,
      participants will have their height and weight measured and will complete a questionnaire on
      reproductive and medical history, migration status and lifestyle factors. Premenopausal blood
      samples with accompanying information on medical history and lifestyle factors from women
      participating in Project Viva in Boston, Massachusetts will provide a comparison group of US
      women at high breast cancer risk.

      In general, Asian countries have been treated as one entity and the substantial variation in
      breast cancer incidence among the countries that make up this large geographic area has not
      been addressed. This variation among Asian countries may provide further opportunity for
      hypothesis generating as we seek to determine what factors explain differences in breast
      cancer rates between populations. Studies of a range of biological parameters in
      premenopausal women among different racial/ethnic populations with varying breast cancer
      incidence would be informative.
    

Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Probability Sample
Study population: 
        Premenopausal women (ages 25-44)in Mongolia. These women were mothers of children attending
        several schools in Ulanbaatar (the capital).
      
Biospecimen description: 
      sera, urine
    
Keywords: Mongolia; Asia; GROWTH FACTORS; Hormones; Premenopausal; Breast Cancer