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Comparison of postmenopausal endogenous sex hormones among Japanese, Japanese Brazilians, and non-Japanese Brazilians
BACKGROUND: Differences in sex hormone levels among populations might contribute to the variation in breast cancer incidence across countries. Previous studies have shown higher breast cancer incidence and mortality among Japanese Brazilians than among Japanese. To clarify the difference in hormone...
Autores principales: | , , , , , , , , , , , , |
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Formato: | Texto |
Lenguaje: | English |
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BioMed Central
2011
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3050759/ https://www.ncbi.nlm.nih.gov/pubmed/21324183 http://dx.doi.org/10.1186/1741-7015-9-16 |
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author | Iwasaki, Motoki Kasuga, Yoshio Yokoyama, Shiro Onuma, Hiroshi Nishimura, Hideki Kusama, Ritsu Hamada, Gerson Shigeaki Nishimoto, Ines Nobuko Maciel, Maria do Socorro Motola, Juvenal Laginha, Fábio Martins Anzai, Roberto Tsugane, Shoichiro |
author_facet | Iwasaki, Motoki Kasuga, Yoshio Yokoyama, Shiro Onuma, Hiroshi Nishimura, Hideki Kusama, Ritsu Hamada, Gerson Shigeaki Nishimoto, Ines Nobuko Maciel, Maria do Socorro Motola, Juvenal Laginha, Fábio Martins Anzai, Roberto Tsugane, Shoichiro |
author_sort | Iwasaki, Motoki |
collection | PubMed |
description | BACKGROUND: Differences in sex hormone levels among populations might contribute to the variation in breast cancer incidence across countries. Previous studies have shown higher breast cancer incidence and mortality among Japanese Brazilians than among Japanese. To clarify the difference in hormone levels among populations, we compared postmenopausal endogenous sex hormone levels among Japanese living in Japan, Japanese Brazilians living in the state of São Paulo, and non-Japanese Brazilians living in the state of São Paulo. METHODS: A cross-sectional study was conducted using a control group of case-control studies in Nagano, Japan, and São Paulo, Brazil. Participants were postmenopausal women older than 55 years of age who provided blood samples. We measured estradiol, estrone, androstenedione, dehydroepiandrosterone sulfate (DHEAS), testosterone and free testosterone by radioimmunoassay; bioavailable estradiol by the ammonium sulfate precipitation method; and sex hormone-binding globulin (SHBG) by immunoradiometric assay. A total of 363 women were included for the present analyses, comprising 185 Japanese, 44 Japanese Brazilians and 134 non-Japanese Brazilians. RESULTS: Japanese Brazilians had significantly higher levels of estradiol, bioavailable estradiol, estrone, testosterone and free testosterone levels, and lower SHBG levels, than Japanese. Japanese Brazilians also had significantly higher levels of bioavailable estradiol, estrone and DHEAS and lower levels of SHBG and androstenedione than non-Japanese Brazilians. Levels of estradiol, testosterone and free testosterone, however, did not differ between Japanese Brazilians and non-Japanese Brazilians. These differences were observed even after adjustment for known breast cancer risk factors. We also found an increase in estrogen and androgen levels with increasing body mass index, but no association for most of the other known risk factors. CONCLUSIONS: We found higher levels of estrogens and androgens in Japanese Brazilians than in Japanese and levels similar to or higher than in non-Japanese Brazilians. Our findings may help explain the increase in the incidence and mortality rate of breast cancer among Japanese Brazilians. |
format | Text |
id | pubmed-3050759 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2011 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-30507592011-03-09 Comparison of postmenopausal endogenous sex hormones among Japanese, Japanese Brazilians, and non-Japanese Brazilians Iwasaki, Motoki Kasuga, Yoshio Yokoyama, Shiro Onuma, Hiroshi Nishimura, Hideki Kusama, Ritsu Hamada, Gerson Shigeaki Nishimoto, Ines Nobuko Maciel, Maria do Socorro Motola, Juvenal Laginha, Fábio Martins Anzai, Roberto Tsugane, Shoichiro BMC Med Research Article BACKGROUND: Differences in sex hormone levels among populations might contribute to the variation in breast cancer incidence across countries. Previous studies have shown higher breast cancer incidence and mortality among Japanese Brazilians than among Japanese. To clarify the difference in hormone levels among populations, we compared postmenopausal endogenous sex hormone levels among Japanese living in Japan, Japanese Brazilians living in the state of São Paulo, and non-Japanese Brazilians living in the state of São Paulo. METHODS: A cross-sectional study was conducted using a control group of case-control studies in Nagano, Japan, and São Paulo, Brazil. Participants were postmenopausal women older than 55 years of age who provided blood samples. We measured estradiol, estrone, androstenedione, dehydroepiandrosterone sulfate (DHEAS), testosterone and free testosterone by radioimmunoassay; bioavailable estradiol by the ammonium sulfate precipitation method; and sex hormone-binding globulin (SHBG) by immunoradiometric assay. A total of 363 women were included for the present analyses, comprising 185 Japanese, 44 Japanese Brazilians and 134 non-Japanese Brazilians. RESULTS: Japanese Brazilians had significantly higher levels of estradiol, bioavailable estradiol, estrone, testosterone and free testosterone levels, and lower SHBG levels, than Japanese. Japanese Brazilians also had significantly higher levels of bioavailable estradiol, estrone and DHEAS and lower levels of SHBG and androstenedione than non-Japanese Brazilians. Levels of estradiol, testosterone and free testosterone, however, did not differ between Japanese Brazilians and non-Japanese Brazilians. These differences were observed even after adjustment for known breast cancer risk factors. We also found an increase in estrogen and androgen levels with increasing body mass index, but no association for most of the other known risk factors. CONCLUSIONS: We found higher levels of estrogens and androgens in Japanese Brazilians than in Japanese and levels similar to or higher than in non-Japanese Brazilians. Our findings may help explain the increase in the incidence and mortality rate of breast cancer among Japanese Brazilians. BioMed Central 2011-02-16 /pmc/articles/PMC3050759/ /pubmed/21324183 http://dx.doi.org/10.1186/1741-7015-9-16 Text en Copyright ©2011 Iwasaki et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Article Iwasaki, Motoki Kasuga, Yoshio Yokoyama, Shiro Onuma, Hiroshi Nishimura, Hideki Kusama, Ritsu Hamada, Gerson Shigeaki Nishimoto, Ines Nobuko Maciel, Maria do Socorro Motola, Juvenal Laginha, Fábio Martins Anzai, Roberto Tsugane, Shoichiro Comparison of postmenopausal endogenous sex hormones among Japanese, Japanese Brazilians, and non-Japanese Brazilians |
title | Comparison of postmenopausal endogenous sex hormones among Japanese, Japanese Brazilians, and non-Japanese Brazilians |
title_full | Comparison of postmenopausal endogenous sex hormones among Japanese, Japanese Brazilians, and non-Japanese Brazilians |
title_fullStr | Comparison of postmenopausal endogenous sex hormones among Japanese, Japanese Brazilians, and non-Japanese Brazilians |
title_full_unstemmed | Comparison of postmenopausal endogenous sex hormones among Japanese, Japanese Brazilians, and non-Japanese Brazilians |
title_short | Comparison of postmenopausal endogenous sex hormones among Japanese, Japanese Brazilians, and non-Japanese Brazilians |
title_sort | comparison of postmenopausal endogenous sex hormones among japanese, japanese brazilians, and non-japanese brazilians |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3050759/ https://www.ncbi.nlm.nih.gov/pubmed/21324183 http://dx.doi.org/10.1186/1741-7015-9-16 |
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