<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>1679-4974</journal-id>
<journal-title><![CDATA[Epidemiologia e Serviços de Saúde]]></journal-title>
<abbrev-journal-title><![CDATA[Epidemiol. Serv. Saúde]]></abbrev-journal-title>
<issn>1679-4974</issn>
<publisher>
<publisher-name><![CDATA[Secretaria de Vigilância em Saúde e Ambiente - Ministério da Saúde do Brasil]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S1679-49742023000100302</article-id>
<article-id pub-id-type="doi">10.1590/s2237-96222023000100020</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Prevalence of sexual initiation and associated factors in school adolescents in Piauí, Brazil, 2015]]></article-title>
<article-title xml:lang="es"><![CDATA[Prevalência y factores asociados a la iniciación sexual en adolescentes escolares de Piauí, Brasil, 2015]]></article-title>
<article-title xml:lang="pt"><![CDATA[Prevalência e fatores associados à iniciação sexual em adolescentes escolares do Piauí, 2015]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Castro]]></surname>
<given-names><![CDATA[Lucélia da Cunha]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Viana]]></surname>
<given-names><![CDATA[Vera Alice Oliveira]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Rufino]]></surname>
<given-names><![CDATA[Andréa Cronemberger]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Madeiro]]></surname>
<given-names><![CDATA[Alberto Pereira]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af2">
<institution><![CDATA[,Universidade Federal do Piauí Programa de Pós-graduação em Saúde e Comunidade ]]></institution>
<addr-line><![CDATA[Teresina PI]]></addr-line>
<country>Brasil</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>00</month>
<year>2023</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>00</month>
<year>2023</year>
</pub-date>
<volume>32</volume>
<numero>1</numero>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://scielo.iec.gov.br/scielo.php?script=sci_arttext&amp;pid=S1679-49742023000100302&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://scielo.iec.gov.br/scielo.php?script=sci_abstract&amp;pid=S1679-49742023000100302&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://scielo.iec.gov.br/scielo.php?script=sci_pdf&amp;pid=S1679-49742023000100302&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract  Objective:  to analyze prevalence of sexual initiation and associated factors in adolescents in Piauí.  Methods: this was a cross-sectional study, with secondary data from the 2015 National Adolescent School-based Health Survey. Hierarchical analysis was performed using robust Poisson regression.  Results: a total of 3.872 adolescents were interviewed. Prevalence of sexual initiation was 24.2%; risk factors for sexual initiation were being male [prevalence ratio (PR) = 2.18; 95% confidence interval (95%CI) 1.90;2.47], being 15 years old or over (PR = 2.49; 95%CI 2.18;2.76), living with mother (PR = 0.68; 95%CI 0.54;0.82), working (PR = 1.82; 95%CI 1.55;2.10), attending a public school (PR = 1.39; 95%CI 1.09;1.75), practicing bullying (PR = 1.50; 95%CI 1.31;1.72), using alcohol (PR = 2.35; 95%CI 2.09;2.64), using cigarettes (PR = 1.46; 95%CI 1.22;1.70) and using illicit drugs (PR = 1.40; 95%CI 1.15;1.66).  Conclusion: prevalence of sexual initiation was high and associated with sociodemographic characteristics and vulnerable health behaviors, indicating the need for health promotion strategies.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen  Objetivo:  analizar prevalencia y factores asociados a la iniciación sexual de adolescentes en Piauí.  Métodos: estudio transversal, con datos de la Encuesta Nacional de Salud Adolescente, 2015. Se realizó análisis jerárquico mediante regresión robusta de Poisson.  Resultados:  han sido entrevistados 3.872 adolescentes. Hubo prevalencia de iniciación sexual del 24,2%, estando asociada con ser hombre (RP = 2,18; IC95% 1,90;2,47), tener 15 años o más (RP = 2.49; IC95% 2,18;2,76), vivir con la madre (RP = 0,68; IC95% 0,54;0,82), trabajar (RP = 1.82; IC95% 1,55;2,10), estudiar en escuela pública (RP = 1,39; IC95% 1,09;1,75), practicar bullying (RP = 1,50; IC95% 1,31;1,72), consumir alcohol (RP = 2.35; IC95% 2,09;2,64), consumir cigarrillos (RP = 1,46; IC95% 1,22;1,70) y consumir drogas ilícitas (RP = 1,40; IC95% 1,15;1,66).  Conclusión:  la prevalencia de iniciación sexual fue alta y se asoció con comportamientos vulnerables a la salud y características sociodemográficas, indicando estrategias para de promoción de la salud.]]></p></abstract>
<abstract abstract-type="short" xml:lang="pt"><p><![CDATA[Resumo  Objetivo: analisar prevalência e fatores associados à iniciação sexual de adolescentes do Piauí.  Métodos:  estudo transversal, com dados da Pesquisa Nacional de Saúde do Escolar, 2015. Realizou-se análise hierarquizada por regressão de Poisson.  Resultados:  foram entrevistados 3.872 adolescentes. A prevalência de iniciação sexual foi de 24,2%; sexo masculino [razão de prevalência (RP) = 2,18; intervalo de confiança de 95% (IC95%) 1,90;2,47], idade &#8805; 15 anos (RP = 2,49; IC95% 2,18;2,76), morar com a mãe (RP = 0,68; IC95% 0,54;0,82), trabalhar (RP = 1,82; IC95% 1,55;2,10). estudar em escola pública (RP = 1,39; IC95% 1,09;1,75), praticar bullying (RP = 1,50; IC95% 1,31;1,72), usar álcool (RP = 2,35; IC95% 2,09;2,64), cigarro (RP = 1,46; IC95% 1,22;1,70) e drogas ilícitas (RP = 1,40; IC95% 1,15;1,66) foram fatores de risco para o evento.  Conclusão:  a prevalência de iniciação sexual foi alta e associada a características sociodemográficas e comportamentos vulneráveis à saúde, demandando estratégias de promoção de saúde.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Sexual and Reproductive Health]]></kwd>
<kwd lng="en"><![CDATA[Sexual Behavior]]></kwd>
<kwd lng="en"><![CDATA[Adolescent Behavior]]></kwd>
<kwd lng="en"><![CDATA[Adolescent Health]]></kwd>
<kwd lng="en"><![CDATA[Student Health]]></kwd>
<kwd lng="en"><![CDATA[Cross-Sectional Studies]]></kwd>
<kwd lng="es"><![CDATA[Salud Sexual y Reproductiva]]></kwd>
<kwd lng="es"><![CDATA[Conducta Sexual]]></kwd>
<kwd lng="es"><![CDATA[Conducta del Adolescente]]></kwd>
<kwd lng="es"><![CDATA[Salud del Adolescente]]></kwd>
<kwd lng="es"><![CDATA[Salud del Estudiante]]></kwd>
<kwd lng="es"><![CDATA[Estudios Transversales]]></kwd>
<kwd lng="pt"><![CDATA[Saúde Sexual e Reprodutiva]]></kwd>
<kwd lng="pt"><![CDATA[Comportamento Sexual]]></kwd>
<kwd lng="pt"><![CDATA[Comportamento do Adolescente]]></kwd>
<kwd lng="pt"><![CDATA[Saúde do Adolescente]]></kwd>
<kwd lng="pt"><![CDATA[Saúde do Estudante]]></kwd>
<kwd lng="pt"><![CDATA[Estudos Transversais]]></kwd>
</kwd-group>
</article-meta>
</front><back>
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