title: Maternal Smoking during Pregnancy, Household Smoking after the Child's Birth, and Childhood Proteinuria at Age 3 Years.
abstract: Smoking is a well known risk factor of proteinuria in adults; however, clinical studies in children are limited. The purpose of this study is to clarify the associations of maternal smoking during pregnancy and household smoking after the child's birth with the risk of proteinuria at age 3 years old.
  
  
  
  We performed a population-based retrospective cohort study on 44,595 children using data on prenatal health checkups, home visit neonatal health checkups, and health checkups at 4, 9, and 18 months and 3 years of age in Kobe City, Japan. Maternal smoking status (nonsmoker, past smoker, or current smoker) was collected with standardized questionnaires. The outcome of interest was the presence of proteinuria at 3 years of age defined as urinary protein ≥1+. To evaluate the association between child proteinuria and smoking status, we performed multivariate logistic regression model analyses adjusted for confounding factors.
  
  
  
  The prevalence rates of children in the maternal smoking groups (none, past, and current) were 78.9%, 4.4%, and 16.7%, respectively. The frequencies of child proteinuria defined as ≥1+ urinary protein were 1.7% in the current smoking group, 1.6% in the past smoking group, and 1.3% in the nonsmoking group. Maternal smoking during pregnancy was associated with child proteinuria (odds ratio, 1.24; 95% confidence interval, 1.00 to 1.52; P=0.05) in the multiple logistic regression model, although nonmaternal family smoking during pregnancy was not significantly associated with child proteinuria (odds ratio, 0.97; 95% confidence interval, 0.79 to 1.19; P=0.77). We also found a similar association with household smoking after the child's birth (odds ratio, 1.23; 95% confidence interval, 0.99 to 1.54; P=0.06), although this observation was not significant.
  
  
  
  Maternal smoking during pregnancy was one of the risk factors of childhood proteinuria. We also found a similar association with household smoking after the child's birth, although this observation was not significant.
authors.affiliation: Department of Pharmacoepidemiology, Graduate School of Medicine and Public Health and.
authors.forename: Maki
authors.initials: M
authors.lastname: Shinzawa
authors.affiliation: Department of Pharmacoepidemiology, Graduate School of Medicine and Public Health and.
authors.forename: Shiro
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Pharmacoepidemiology, Graduate School of Medicine and Public Health and.
authors.forename: Hironobu
authors.initials: H
authors.lastname: Tokumasu
authors.affiliation: Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takada
authors.affiliation: Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Tsukamoto
authors.affiliation: Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Motoko
authors.initials: M
authors.lastname: Yanagita
authors.affiliation: Department of Pharmacoepidemiology, Graduate School of Medicine and Public Health and.
authors.forename: Koji
authors.initials: K
authors.lastname: Kawakami
mesh_terms: D000328:Adult; D002675:Child, Preschool; D004781:Environmental Exposure / Q000009:adverse effects / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008297:Male; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*; D015995:Prevalence; D011507:Proteinuria / Q000453:epidemiology*; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology*; D014028:Tobacco Smoke Pollution / Q000009:adverse effects / Q000706:statistics & numerical data*
chemical_list: D014028:Tobacco Smoke Pollution
keywords: Kobe Offspring Study; childhood proteinuria; household smoking; maternal smoking