<?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>0034-8376</journal-id>
<journal-title><![CDATA[Revista de investigación clínica]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. invest. clín.]]></abbrev-journal-title>
<issn>0034-8376</issn>
<publisher>
<publisher-name><![CDATA[Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0034-83762019000100064</article-id>
<article-id pub-id-type="doi">10.24875/ric.18002648</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Symptomatic and Asymptomatic Smokers without Airflow Obstruction: A New Clinical Entity?]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Hernández-Zenteno]]></surname>
<given-names><![CDATA[Rafael de Jesús]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Flores-Trujillo]]></surname>
<given-names><![CDATA[Fernando]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Vázquez-Cortés]]></surname>
<given-names><![CDATA[Jesús Javier]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Espinosa de los Monteros-Sánchez]]></surname>
<given-names><![CDATA[Carlos]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Cosío]]></surname>
<given-names><![CDATA[Manuel G.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas  ]]></institution>
<addr-line><![CDATA[Mexico City ]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Hospital Ángeles Lomas  ]]></institution>
<addr-line><![CDATA[Estado de Mexico ]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,University of Padova Department of Cardiac, Thoracic, and Vascular Sciences ]]></institution>
<addr-line><![CDATA[Padova ]]></addr-line>
<country>Italy</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>02</month>
<year>2019</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>02</month>
<year>2019</year>
</pub-date>
<volume>71</volume>
<numero>1</numero>
<fpage>64</fpage>
<lpage>69</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0034-83762019000100064&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0034-83762019000100064&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0034-83762019000100064&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract Non-obstructed ever-smokers, with or without symptoms, have generated a great deal of information recently, but few reviews. Even individuals with normal spirometry can present changes in sputum with inflammatory biomarkers (cellular and molecular) and airways and parenchyma with remodeling; when symptomatic (cough, sputum, wheezing, and dyspnea) exacerbations are frequent affecting the individuals’ quality of life, there is an increased use of health resources: more medication, emergency visits, and hospital admissions. Non-obstructed smokers may have exercise limitations, increased lung volumes, low diffusion capacity, air entrapment, peripheral airways obstruction, elevated airways resistance, and abnormal multiple breath nitrogen washout, as well as abnormalities in computed tomography studies, such as airway wall thickening, emphysema, or interstitial lung abnormalities. Quitting smoking comprises a first, inexpensive, and often abandoned intervention to arrest respiratory impairment. It is controversial whether or not this population should be treated with other medications. Further studies should be conducted to elucidate the consequences of follow-up and prognosis in this clinical entity.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Normal smokers]]></kwd>
<kwd lng="en"><![CDATA[Healthy smokers]]></kwd>
<kwd lng="en"><![CDATA[Non-obstructed smokers]]></kwd>
<kwd lng="en"><![CDATA[Symptomatic smokers]]></kwd>
<kwd lng="en"><![CDATA[Global initiative for chronic obstructive lung disease 0]]></kwd>
</kwd-group>
</article-meta>
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