<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="static/style.xsl"?><OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd"><responseDate>2026-04-13T15:16:58Z</responseDate><request verb="GetRecord" identifier="oai:www.recercat.cat:20.500.14342/4578" metadataPrefix="marc">https://recercat.cat/oai/request</request><GetRecord><record><header><identifier>oai:recercat.cat:20.500.14342/4578</identifier><datestamp>2025-05-15T19:20:24Z</datestamp><setSpec>com_2072_482405</setSpec><setSpec>com_2072_183628</setSpec><setSpec>col_2072_482409</setSpec></header><metadata><record xmlns="http://www.loc.gov/MARC21/slim" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:doc="http://www.lyncode.com/xoai" xsi:schemaLocation="http://www.loc.gov/MARC21/slim http://www.loc.gov/standards/marcxml/schema/MARC21slim.xsd">
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      <subfield code="a">Hernáez, Álvaro</subfield>
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      <subfield code="a">Wootton, Robyn E.</subfield>
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      <subfield code="a">Page, Christian Magnus</subfield>
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      <subfield code="a">Skåra, Karoline Hansen</subfield>
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      <subfield code="a">Fraser, Abigail</subfield>
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      <subfield code="a">Rogne, Tormod</subfield>
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      <subfield code="a">Magnus, Per</subfield>
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      <subfield code="a">Njølstad, Pål R.</subfield>
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      <subfield code="a">Andreassen, Ole A.</subfield>
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      <subfield code="a">Burgess, Stephen</subfield>
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      <subfield code="a">Lawlor, Deborah A.</subfield>
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      <subfield code="a">Magnus, Maria Christine</subfield>
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      <subfield code="c">2022-07</subfield>
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      <subfield code="a">Objective&#xd;
To investigate the association between smoking and infertility.&#xd;
Design&#xd;
Prospective study.&#xd;
Setting&#xd;
Nationwide cohort.&#xd;
Patients&#xd;
28,606 women and 27,096 men with questionnaire and genotype information from the Norwegian Mother, Father, and Child Cohort Study.&#xd;
Intervention&#xd;
Self-reported information on smoking (having ever smoked [both sexes], age at initiation [women only], cessation [women only], and cigarettes/week in current smokers [both sexes]) was gathered. Genetically predetermined levels or likelihood of presenting these traits were estimated for Mendelian randomization.&#xd;
Main outcome measure&#xd;
Infertility (time-to-pregnancy ≥12 months).&#xd;
Results&#xd;
Having ever smoked was unrelated to infertility in women or men. Higher smoking intensity in women was associated with greater infertility odds (+1 standard deviation [SD, 48 cigarettes/week]: odds ratio [OR]crude, 1.19; 95% confidence interval [CI] 1.11–1.28; ORadjusted 1.12; 95% CI, 1.03–1.21), also after adjusting for the partner’s tobacco use. Later smoking initiation (+1 SD [3.2 years]: ORcrude, 0.94; 95% CI, 0.88–0.99; ORadjusted 0.89; 95% CI, 0.84–0.95) and smoking cessation (vs. not quitting: ORcrude, 0.83; 95% CI, 0.75–0.91; ORadjusted, 0.83; 95% CI, 0.75–0.93) were linked to decreased infertility in women. Nevertheless, Mendelian randomization results were not directionally consistent for smoking intensity and cessation and were estimated imprecisely in the 2-sample approach. In men, greater smoking intensity was not robustly associated with infertility in multivariable regression and Mendelian randomization.&#xd;
Conclusions&#xd;
We did not find robust evidence of an effect of smoking on infertility. This may be due to a true lack of effect, weak genetic instruments, or other kinds of confounding.&#xd;
Tabaquismo e infertilidad: regresión multivariable y análisis de aleatorización mendeliana en el estudio de cohorte noruego de madre, padre e hijo.</subfield>
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      <subfield code="a">http://hdl.handle.net/20.500.14342/4578</subfield>
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   <datafield ind1="8" ind2=" " tag="024">
      <subfield code="a">https://doi.org/10.1016/j.fertnstert.2022.04.001</subfield>
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   <datafield tag="653" ind2=" " ind1=" ">
      <subfield code="a">Hàbit de fumar</subfield>
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      <subfield code="a">Esterilitat</subfield>
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      <subfield code="a">Aleatorització Mendeliana</subfield>
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   <datafield ind2="0" ind1="0" tag="245">
      <subfield code="a">Smoking and infertility: multivariable regression and Mendelian randomization analyses in the Norwegian Mother, Father and Child Cohort Study</subfield>
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