Determinants of self-reported smoking and misclassification during pregnancy, and analysis of optimal cut-off points for urinary cotinine: a cross-sectional study

10 p.Objectives: To estimate the prevalence and factors associated with smoking and misclassification in pregnant women from INMA (INfancia y Medio Ambiente, Environment and Childhood) project, Spain, and to assess the optimal cut-offs for urinary cotinine (UC) that best distinguish daily and occasional smokers with varying levels of second-hand smoke (SHS) exposure.-- Design: We used logistic regression models to study the relationship between sociodemographic variables and self-reported smoking and misclassification (self-reported non-smokers with UC >50 ng/ml). Receiver operating characteristic (ROC) curves were used to calculate the optimal cut-off point for discriminating smokers. The cut-offs were also calculated after stratification among non-smokers by the number of sources of SHS exposure. The cut-off points used to discriminate smoking status were the level of UC given by Youden's index and for 50 and 100 ng/ml for daily smokers, or 25 and 50 ng/ml for occasional smokers. -- Participants: At the third trimester of pregnancy, 2263 pregnant women of the INMA Project were interviewed between 2004 and 2008 and a urine sample was collected. -- Results: Prevalence of self-reported smokers at the third trimester of pregnancy was 18.5%, and another 3.9% misreported their smoking status. Variables associated with self-reported smoking and misreporting were similar, including born in Europe, educational level and exposure to SHS. The optimal cut-off was 82 ng/ml (95% CI 42 to 133), sensitivity 95.2% and specificity 96.6%. The area under the ROC curve was 0.986 (95% CI 0.982 to 0.990). The cut-offs varied according to the SHS exposure level being 42 (95% CI 27 to 57), 82 (95% CI 46 to 136) and 106 ng/ml (95% CI 58 to 227) for not being SHS exposed, exposed to one, and to two or more sources of SHS, respectively. The optimal cut-off for discriminating occasional smokers from non-smokers was 27 ng/ml (95% CI 11 to 43). -- Conclusions: Prevalence of smoking during pregnancy in Spain remains high. UC is a reliable biomarker for classifying pregnant women according to their smoking status. However, cut-offs would differ based on baseline exposure to SHS.The INMA project is funded by grants from Instituto de Salud Carlos III (Red INMA G03/176 and CB06/02/0041) and Fundación Roger Torné. The studies in the specific regions were funded by the Spanish Ministry of Health (FIS 03/1615, 04/1436, 04/1509, 04/1112, 04/1931, 05/1079, 05/1052, 06/0867,06/1213, 07/0314, 08/1151, 09/02647, 04/2018, 09/02311), the Generalitat de Catalunya (CIRIT 1999SGR00241), the Diputación Foral de Gipuzkoa (DFG06/004), the Department of Health of the Basque Government (2005111093), the Regional Government of Andalucía (SAS 07/183), Obra social Cajastur, University of Oviedo and the Conselleria de Sanitat Generalitat Valenciana. http://www.proyectoinma.org/instituciones-participantes/en_entidades-colaboradoras/

Second-hand smoke exposure in 4-year-old children in Spain: Sources, associated factors and urinary cotinine

Introduction Second-hand smoke exposure (SHS) in children remains as a major pollution problem, with important consequences for children's health. This study aimed to identify the sources of exposure to SHS among 4-year-old children, comparing self-reports to a urinary biomarker of exposure, and characterize the most important variables related to SHS exposure in this population. Methods 4-year-old children's exposure to SHS was assessed by a parental-reported questionnaire and by urinary cotinine (UC) measurements in 1757 participants from 4 different areas of the Spanish INMA (INfancia y Medio Ambiente – Environment and Childhood) Project. The questionnaire about SHS included information about smoking habits at home by household members, and about exposure to SHS in other places including other homes, bars, restaurants or transportation. The association between quantified UC levels (>4 ng/ml) and sociodemographic variables and the different sources of SHS exposure was examined using logistic regression. Results Based on parental reports, 21.6% of the children were exposed to SHS at home and 47.1% elsewhere; making a total 55.9% of the children exposed to SHS. In addition, 28.2% of the children whose parents reported being not regularly exposed to SHS had quantified UC values. Children from younger mothers (<34 vs. ≥39.4 y) had a higher odds of exposure to SHS [OR (95% CI): 2.28 (1.70–3.05) per year], as well as from families with a lower educational level [OR secondary: 2.12 (1.69–2.65); primary or less: 2.91 (2.19–3.88)]. The odds of quantifiable UC in children dropped after the smoking ban in public places [OR=0.59 (0.42–0.83)]. Regarding the sources of SHS exposure we observed that quantifiable UC odds was increased in children whose parents smoked at home in their presence [OR mother occasionally: 13.39 (7.03–25.50); mother often: 18.48 (8.40–40.66); father occasionally: 10.98 (6.52–18.49); father often: 11.50 (5.96–22.20)] or in children attending other confined places, mainly other houses where people smoked [OR: 2.23 (1.78–2.80)]. Conclusions Children's SHS exposure is nowadays an unresolved major public health problem in Spain. After the ban of smoking in public places health care professionals should put more emphasis to the parents on the importance of controlling the exposure of their children in private spaces.INMA project is funded by grants by the Carlos III Instituto de Salud (Red INMA G03/176 and CB06/02/0041) and Fundación Roger Torné. The studies in the specific regions were funded by the Spanish Ministry of Health (FIS-FEDER 03/1615, 04/1436, 04/1509, 04/1112, 04/1931, 05/1079, 05/1052, 06/0867, 06/1213, 07/0314, 08/1151, 09/02647, 04/2018, 09/02311, 11/02591, 11/02038, 13/02032, 13/02429, 14/0891, 14/1687, and MS13/00054), the Generalitat de Catalunya (CIRIT 1999SGR00241), the Diputación Foral de Gipuzkoa (DFG06/004), the Department of Health of the Basque Government (2005111093), the Regional Government of Andalucía (SAS 07/183), and support of Obra Social Cajastur/Fundación Liberbank, University of Oviedo and the Conselleria de Sanitat Generalitat Valenciana. http://www.proyectoinma.org/instituciones-participantes/en_entidades-colaboradoras/. The authors are grateful to all fieldworkers for their assistance in administering the questionnaires. A full listing of the INMA project researchers can be found at http://www.proyectoinma.org/presentacioninma/listado-investigadores/en_listado-investigadores.htm

Clinical validation of cutoff target ranges in newborn screening of metabolic disorders by tandem mass spectrometry: A worldwide collaborative project

PURPOSE:: To achieve clinical validation of cutoff values for newborn screening by tandem mass spectrometry through a worldwide collaborative effort. METHODS:: Cumulative percentiles of amino acids and acylcarnitines in dried blood spots of approximately 25-30 million normal newborns and 10,742 deidentified true positive cases are compared to assign clinical significance, which is achieved when the median of a disorder range is, and usually markedly outside, either the 99th or the 1st percentile of the normal population. The cutoff target ranges of analytes and ratios are then defined as the interval between selected percentiles of the two populations. When overlaps occur, adjustments are made to maximize sensitivity and specificity taking all available factors into consideration. RESULTS:: As of December 1, 2010, 130 sites in 45 countries have uploaded a total of 25,114 percentile data points, 565,232 analyte results of true positive cases with 64 conditions, and 5,341 cutoff values. The average rate of submission of true positive cases between December 1, 2008, and December 1, 2010, was 5.1 cases/day. This cumulative evidence generated 91 high and 23 low cutoff target ranges. The overall proportion of cutoff values within the respective target range was 42% (2,269/5,341). CONCLUSION:: An unprecedented level of cooperation and collaboration has allowed the objective definition of cutoff target ranges for 114 markers to be applied to newborn screening of rare metabolic disorders. © 2011 Lippincott Williams &amp; Wilkins