Journal article
Dietary phytoestrogen intakes of adult women are not strongly related to fecundability in 2 preconception cohort studies
Boston University1
Aarhus University Hospital2
National Food Institute, Technical University of Denmark3
Research group for Nutrition and Health Promotion, National Food Institute, Technical University of Denmark4
Roswell Park Comprehensive Cancer Center5
National Institute for Health and Welfare6
University of Massachusetts7
Background Phytoestrogens are plant-derived hormonally active compounds found in soy, cruciferous vegetables, nuts, and seeds. Although phytoestrogens have been associated with altered endogenous hormonal activity, luteal phase deficiency, and reduced endometrial decidualization, the literature reporting examinations of phytoestrogen intake and fertility presents mixed findings.
Objectives We sought to evaluate prospectively the association between dietary phytoestrogen intake (isoflavones, lignans, and coumestans) and fecundability, the per-cycle probability of conception, in 2 cohorts of women planning pregnancy. Methods Pregnancy Study Online (PRESTO) and Snart Foraeldre (SF) are parallel web-based preconception cohort studies of women from North America and Denmark, respectively, who are trying to conceive.
Participants complete an online baseline questionnaire on sociodemographic, lifestyle, and medical factors. We ascertained intake of individual phytoestrogens from validated FFQs. We measured fecundability using data on menstruation and pregnancy status from bimonthly follow-up questionnaires. We analyzed data from 4880 PRESTO and 2898 SF female study participants who had been attempting conception for ≤6 cycles at study entry.
We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% CIs. Results Phytoestrogen intake varied across cohorts, yet was associated with higher socioeconomic status and healthier behaviors in both cohorts. After adjustment for potential confounders, phytoestrogen intake was not substantially associated with fecundability in either cohort.
We observed some evidence of improved fecundability with increasing isoflavone intake among women age ≥30 years in PRESTO (FR: 1.12; 95% CI: 0.94, 1.34, for comparison of ≥90th with <25th percentile intake) and SF (corresponding FR: 1.19; 95% CI: 0.92, 1.55). Lignan intake was associated with slightly increased fecundability in SF (FR for comparison of 75th to 90th with <25th percentile: 1.10; 95% CI: 0.96, 1.26), but decreased fecundability in PRESTO (FR for comparison of ≥90th with <25th percentile: 0.83; 95% CI: 0.72, 0.97).
Conclusions We did not observe strong associations between phytoestrogen intake and prospectively-measured fecundability among North American or Danish pregnancy planners.
Language: | English |
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Year: | 2020 |
Pages: | 1240-1251 |
ISSN: | 15416100 and 00223166 |
Types: | Journal article |
DOI: | 10.1093/jn/nxz335 |
ORCIDs: | Trolle, Ellen |
Adult Body Mass Index Cohort Studies Coumarins Denmark Diet Educational Status Female Fertility Fertilization Humans Income Isoflavones Lignans North America Phytoestrogens Pregnancy Prospective Studies coumestan fecundability isoflavones lignans phytoestrogens preconception time to pregnancy