title: Comparison of secondhand smoke exposure measures during pregnancy in the development of a clinical prediction model for small-for-gestational-age among non-smoking Chinese pregnant women.
abstract: OBJECTIVE
  To compare predictive values of small-for-gestational-age (SGA) by different measures for secondhand smoke (SHS) exposure during pregnancy and to develop and validate a prediction model for SGA using SHS exposure along with sociodemographic and pregnancy factors.
  
  
  METHODS
  We compared the predictability of different measures of SHS exposure during pregnancy for SGA among 545 Chinese pregnant women, and then used the optimal SHS measure along with other clinically available factors to develop and validate a prediction model for SGA. We fit logistic regression models to predict SGA by single measures of SHS exposure (self-report, serum cotinine and CYP2A6*4) and different combinations (self-report+cotinine, cotinine+CYP2A6*4, self-report+CYP2A6*4 and self-report+cotinine+CYP2A6*4).
  
  
  RESULTS
  We found that self-reported SHS exposure alone predicted SGA (area under the receiver operating characteristic curve or area under the receiver operating curve (AUROC), 0.578) better than the other two single measures (cotinine, 0.547; CYP2A6*4, 0.529) or as accurately as combined SHS measures (0.545-0.584). The final prediction model that contained self-reported SHS exposure, prepregnancy body mass index, gestational weight gain velocity during the second and third trimesters, gestational diabetes, gestational hypertension and the third-trimester biparietal diameter Z-score could predict SGA fairly accurately (AUROC, 0.698).
  
  
  CONCLUSIONS
  Self-reported SHS exposure at peribirth performs better in predicting SGA than a single measure of serum cotinine at the same time, although repeated biochemical cotinine assessments throughout pregnancy may be optimal. Our simple prediction model is fairly accurate and can be potentially used in routine prenatal care.
authors: Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, Guangzhou, China.
authors: Chuanbo
authors: C
authors: Xie
authors: Division of Behavioural Medicine, Department of Pediatrics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA.
authors: Xiaozhong
authors: X
authors: Wen
authors: Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, Guangzhou, China.
authors: Zhongzheng
authors: Z
authors: Niu
authors: Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, Guangzhou, China.
authors: Peng
authors: P
authors: Ding
authors: Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China.
authors: Tao
authors: T
authors: Liu
authors: Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China.
authors: Yanhui
authors: Y
authors: He
authors: Shenzhen Women and Children's Hospital, Shenzhen, China.
authors: Jianmiao
authors: J
authors: Lin
authors: Shenzhen Women and Children's Hospital, Shenzhen, China.
authors: Shixin
authors: S
authors: Yuan
authors: Foshan Women and Children's Hospital, Foshan, China.
authors: Xiaoling
authors: X
authors: Guo
authors: Foshan Women and Children's Hospital, Foshan, China.
authors: Deqin
authors: D
authors: Jia
authors: Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, Guangzhou, China.
authors: Weiqing
authors: W
authors: Chen
mesh_terms: D000328:Adult; D019540:Area Under Curve; D001724:Birth Weight; D002681:China; D003367:Cotinine / Q000097:blood; D005260:Female; D006801:Humans; D007236:Infant, Small for Gestational Age; D016015:Logistic Models; D018811:Maternal Exposure; D008954:Models, Biological; D011247:Pregnancy; D037841:Pregnant People; D012372:ROC Curve; D015203:Reproducibility of Results; D057566:Self Report; D012907:Smoking; D014028:Tobacco Smoke Pollution / Q000009:adverse effects* / Q000032:analysis; D055815:Young Adult
chemical_list: D014028:Tobacco Smoke Pollution; D003367:Cotinine
keywords: Cotinine; Secondhand smoke; Smoking Caused Disease