Environmental tobacco smoke exposure in children: parental perception of smokiness at home and other factors associated with urinary cotinine in preschool children DOLORES JURADO, a CARMEN MUN ˜ OZ, a JUAN DE DIOS LUNA b AND MILAGROS FERNA ´ NDEZ-CREHUET a a Department of Preventive Medicine and Public Health, University of Granada, Spain b Department of Statistics, University of Granada, Spain Parental smoking behavior at home and sociodemographic variables may influence exposure to environmental tobacco smoke (ETS) in children. A sampleof115preschoolchildrenaged3–6yearswasenrolledinthisstudy.ETSexposurewasevaluatedthroughaquestionnaireaboutparents’smoking behavior and determinations of urinary cotinine F a biomarker of exposure F in children. Bivariate and multiple regression analyses were used to evaluate the association between the smoking behavior of each parent at home, sociodemographic factors and cotinine levels in children. The parental perception of smokiness in the home was significantly associated with urinary cotinine in children (r-partial coefficient ¼ 0.324; Po0.002).Thefather’s education,mother’ssmokingstatus,anddayoftheweekwhenurinewassampled(Tuesday)werealsoindependentlyassociatedwithlevelsofcotinine. These four variables explained 26.4% of the variance in the cotinine levels of children. In designing educational programs to reduce passive smoking amongchildren,itisnecessarytotakeintoaccountthosefactorsrelatedwithcotininelevelsinchildren.Ourresultssupporttheinfluenceofthemothers’ smoking status, the fathers’ educational level, and the day of the week of sampling on cotinine in children. The perception of parents (smokers and nonsmokers)aboutthesmokinessinthehomecouldalsobeausefulindicatorofthecotinineinchildrenexposedtoenvironmentaltobaccosmokeinthe household. Journal of Exposure Analysis and Environmental Epidemiology (2004) 14, 330–336.doi:10.1038/sj.jea.7500329 Keywords: environmental tobacco smoke, passive smoking, cotinine, child, preschool, smoking, parent–child relations. Introduction Exposure to environmental tobacco smoke (ETS) is an important preventable cause of morbidity and mortality in children (Aligne and Stoddard, 1997). Health effects of children’s passive smoking, through prenatal and/or post- natal exposure, have been well documented (US Environ- mental Protection Agency, 1992; World Health Organization, 1999). Parental smoking at home is the single most important source of passive exposure in childhood (Cook et al., 1994; Dell’Orco et al., 1995; Bakoula et al., 1997; Irvine et al., 1997; Winkelstein et al., 1997; Jordaan et al., 1999), although other family members, caregivers, visitors or friends may also contribute to the level of smokiness in the home (Cook et al., 1994; Irvine et al., 1997; Preston et al., 1997; Ownby et al., 2000). The combination of a questionnaire about parents’ smoking behavior and determinations of cotinine (a biomarker of exposure) in organic fluids of children can be applied in epidemiologicstudiestoassessETSexposureamongchildren (Dell’Orco et al., 1995; Bakoula et al., 1997; Irvine et al., 1997;Petersonetal.,1997;Prestonetal.,1997;Winkelstein et al., 1997; Bahc ¸ eciler et al., 1999; Jordaan et al., 1999; Oddoze et al., 1999; Seifert et al., 2002). Thecotininelevelsinchildren,measuredinsalivaorurine, increase with the number of smoking parents (Cook et al., 1994;Irvineetal.,1997;Seifertetal.,2002),thenumberof smokers in the household (Jordaan et al. 1999), the number of cigarettes/day that the parents smoke at home (Bakoula etal.,1997;Irvineetal.,1997;Oddozeetal.,1999)andthe number of cigarettes/day that household members (parents andothers)smokeathome(Prestonetal.,1997;Winkelstein et al., 1997; Manino et al., 2001; Callais et al., 2003). Moreover,thecotinineissubstantiallyreducedwhenparents donotsmokeinthepresenceoftheirchildren(Bakoulaetal., 1997; Irvine et al., 1997; Seifert et al., 2002), and increases progressivelywiththefrequencyofsmokingintheirpresence (Irvine et al., 1997). Urinary cotinine has been found to be inversely related to theageofthechild(Bakoulaetal.,1997;Irvineetal.,1997; Preston et al., 1997) and to be greater in girls than in boys (Jarvis et al., 1992; Cook et al., 1994; Bakoula et al., 1997; Jordaan et al., 1999). Other studies, however, have not observedtheeffectofage(Cooketal.,1994;Dell’Orcoetal., Received March 2003; accepted 28 October 2003 1. Address all correspondence to: D. Jurado, Departamento de Medicina Preventiva y Salud Pu´blica, Facultad de Medicina, Avda. Madrid, 11, 18012 Granada, Spain. Tel: þ 34-958-243544. Fax: þ 34-958-246118. E-mail: djurado@.ugr.es Journal of Exposure Analysis and Environmental Epidemiology (2004) 14, 330–336 r 2004 Nature Publishing Group All rights reserved 1053-4245/04/$30.00 www.nature.com/jea