CotinineTobacco Smoke PollutionSmokingNicotineSalivaTobacco Use DisorderEnvironmental ExposureBiological MarkersPyrrolidinonesSmoking CessationDistrict of ColumbiaSelf DisclosureAir Pollution, IndoorMaternal ExposureCarbon MonoxideLinear ModelsNutrition SurveysCross-Sectional StudiesPregnancyEuropean Continental Ancestry GroupAfrican AmericansAfrican Continental Ancestry GroupQuestionnairesParentsBirth WeightRisk FactorsNitrosaminesCohort StudiesRegression AnalysisSensitivity and SpecificityInfant, NewbornCase-Control StudiesConfidence IntervalsGanglionic StimulantsNicotinic AgonistsMultivariate Analysis