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Lifetime number of years of menstruation as a risk index for postmenopausal endometrial cancer in the Norwegian Women and Cancer Study
INTRODUCTION: Lifetime number of years of menstruation (LNYM) reflects a woman's cumulative exposure to endogenous estrogen and can be used as a measure of the combined effect of reproductive factors related to endometrial cancer (EC) risk. MATERIAL AND METHODS: We aimed to study the associatio...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6175350/ https://www.ncbi.nlm.nih.gov/pubmed/29782643 http://dx.doi.org/10.1111/aogs.13381 |
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author | Gavrilyuk, Oxana Braaten, Tonje Weiderpass, Elisabete Licaj, Idlir Lund, Eiliv |
author_facet | Gavrilyuk, Oxana Braaten, Tonje Weiderpass, Elisabete Licaj, Idlir Lund, Eiliv |
author_sort | Gavrilyuk, Oxana |
collection | PubMed |
description | INTRODUCTION: Lifetime number of years of menstruation (LNYM) reflects a woman's cumulative exposure to endogenous estrogen and can be used as a measure of the combined effect of reproductive factors related to endometrial cancer (EC) risk. MATERIAL AND METHODS: We aimed to study the association between LNYM and EC risk among postmenopausal women and calculate the population attributable fraction of EC for different LNYM categories. Our study sample consisted of 117 589 women from the Norwegian Women and Cancer (NOWAC) Study. All women were aged 30‐70 years at enrollment and completed a baseline questionnaire between 1991 and 2006. Women were followed up for EC to December 2014 through linkages to national registries. We used Cox proportional hazards models to estimate hazard ratios with 95% confidence intervals (95% CIs), adjusted for potential confounders. RESULTS: In all, 720 women developed EC. We found a statistically significant, positive dose‐response relationship between LNYM and EC, with a 9.1% higher risk for each additional year of LNYM (P for trend < .001). Using the LNYM category ≥40 as a reference, the hazard ratios for LNYM <25, 25‐29, 30‐34, 35‐39 were 0.17 (95% CI 0.22‐0.27), 0.25 (95% CI 0.17‐0.36), 0.43 (95% CI 0.32‐0.58), and 0.68 (95% CI 0.51‐0.92), respectively. The association between LNYM and EC was independent of incomplete pregnancies, menopausal hormone therapy, diabetes, and body mass index. When considering the population attributable fraction, 67% of EC was estimated to be attributable to LNYM ≥25 years. CONCLUSIONS: Our study supports that increasing LNYM is an important and independent predictor of EC risk. |
format | Online Article Text |
id | pubmed-6175350 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-61753502018-10-19 Lifetime number of years of menstruation as a risk index for postmenopausal endometrial cancer in the Norwegian Women and Cancer Study Gavrilyuk, Oxana Braaten, Tonje Weiderpass, Elisabete Licaj, Idlir Lund, Eiliv Acta Obstet Gynecol Scand Oncology INTRODUCTION: Lifetime number of years of menstruation (LNYM) reflects a woman's cumulative exposure to endogenous estrogen and can be used as a measure of the combined effect of reproductive factors related to endometrial cancer (EC) risk. MATERIAL AND METHODS: We aimed to study the association between LNYM and EC risk among postmenopausal women and calculate the population attributable fraction of EC for different LNYM categories. Our study sample consisted of 117 589 women from the Norwegian Women and Cancer (NOWAC) Study. All women were aged 30‐70 years at enrollment and completed a baseline questionnaire between 1991 and 2006. Women were followed up for EC to December 2014 through linkages to national registries. We used Cox proportional hazards models to estimate hazard ratios with 95% confidence intervals (95% CIs), adjusted for potential confounders. RESULTS: In all, 720 women developed EC. We found a statistically significant, positive dose‐response relationship between LNYM and EC, with a 9.1% higher risk for each additional year of LNYM (P for trend < .001). Using the LNYM category ≥40 as a reference, the hazard ratios for LNYM <25, 25‐29, 30‐34, 35‐39 were 0.17 (95% CI 0.22‐0.27), 0.25 (95% CI 0.17‐0.36), 0.43 (95% CI 0.32‐0.58), and 0.68 (95% CI 0.51‐0.92), respectively. The association between LNYM and EC was independent of incomplete pregnancies, menopausal hormone therapy, diabetes, and body mass index. When considering the population attributable fraction, 67% of EC was estimated to be attributable to LNYM ≥25 years. CONCLUSIONS: Our study supports that increasing LNYM is an important and independent predictor of EC risk. John Wiley and Sons Inc. 2018-07-16 2018-10 /pmc/articles/PMC6175350/ /pubmed/29782643 http://dx.doi.org/10.1111/aogs.13381 Text en © 2018 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG). This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. |
spellingShingle | Oncology Gavrilyuk, Oxana Braaten, Tonje Weiderpass, Elisabete Licaj, Idlir Lund, Eiliv Lifetime number of years of menstruation as a risk index for postmenopausal endometrial cancer in the Norwegian Women and Cancer Study |
title | Lifetime number of years of menstruation as a risk index for postmenopausal endometrial cancer in the Norwegian Women and Cancer Study |
title_full | Lifetime number of years of menstruation as a risk index for postmenopausal endometrial cancer in the Norwegian Women and Cancer Study |
title_fullStr | Lifetime number of years of menstruation as a risk index for postmenopausal endometrial cancer in the Norwegian Women and Cancer Study |
title_full_unstemmed | Lifetime number of years of menstruation as a risk index for postmenopausal endometrial cancer in the Norwegian Women and Cancer Study |
title_short | Lifetime number of years of menstruation as a risk index for postmenopausal endometrial cancer in the Norwegian Women and Cancer Study |
title_sort | lifetime number of years of menstruation as a risk index for postmenopausal endometrial cancer in the norwegian women and cancer study |
topic | Oncology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6175350/ https://www.ncbi.nlm.nih.gov/pubmed/29782643 http://dx.doi.org/10.1111/aogs.13381 |
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