Study of Pregnancy Hormone Concentrations in Urban and Nomadic Mongolian Women
Condition: Pregnancy
Study type: Observational

Summary: 
      International variation in breast cancer rates and data from migrant and animal studies
      support the possibility that exposures early in development, including the in utero period,
      play a role in breast carcinogenesis. One of the most striking prenatal influences on breast
      cancer risk is whether the woman was born in a country with a low or high breast cancer
      incidence. This observation has led to interest in the degree to which in utero exposures
      vary by the maternal environment, and to the hypothesis that alterations in prenatal
      concentrations of steroid hormones, particularly estrogens, and other biologic parameters to
      which the fetus is exposed mediate differences in subsequent breast cancer risk.

      There are striking differences in breast cancer incidence rates between Asian and North
      American and Western European populations, but variation within Asia 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. 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. 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 maternal and cord blood samples from pregnant Mongolian women and their
      offspring living in rural and urban areas to describe concentrations of several steroid
      hormones and growth factors. The purpose of the study is to assess whether the in utero
      environment differs in women living a traditional lifestyle compared with a more urban
      lifestyle, and by degree of western acculturation among those who have recently migrated to
      the capital. Maternal and cord blood samples from an ongoing cohort study being conducted at
      the University of Pittsburgh will provide a comparison group of US women.
    

Detailed description: 
      The National Cancer Institute has been conducting research in countries around the world with
      the purpose of documenting international differences in hormone and growth factor levels with
      the intent of trying to understand how these relate to health. In particular, recent evidence
      suggests that hormones and growth factors very early in life may affect later disease risk.
      Dr. Ganmaa, a native Mongolian physician and Harvard-trained scientist suggested including
      Mongolia as one of the research settings for the NCI multi-centered study since the country
      offers a distinct population with unique lifestyles and traditions.

      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. 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.

      Mongolia provides a unique opportunity to assess whether differences in urban and rural
      lifestyles and behaviors influence health. The purpose of the study is to assess whether the
      pregnancy environment differs in women living a traditional lifestyle compared with a more
      urban lifestyle, and by degree of western acculturation among those who have recently
      migrated to the capital. We plan to compare steroid hormones and growth factors in maternal
      and cord blood samples from pregnant Mongolian women living in rural and urban areas with
      pregnant women from the US (at Brigham and Women's Hospital in Boston), UK (the Avon
      Longitudinal Study of Parents and Children), Norway (the Norwegian Mother and Child Cohort)
      and outside Beijing, China (CDC's randomized trial of pregnancy supplements).
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Maternal and cord blood samples from pregnant Mongolian women and their offspring living in
        rural and urban areas (by administrative divisions, called aimags).
      
Keywords: Pregnancy; Hormones; Mongolia; Asian; Breast Cancer