title: A population-based case-control study of risk factors for neural tube defects in Shenyang, China.
abstract: OBJECTIVE
  To explore the risk factors for neural tube defects (NTD) in Shenyang, we carried out a population-based case-control study.
  
  
  METHODS
  We used chi-square test or Fisher's exact test to evaluate variations in the prevalence by selected covariates. Adjusted odds ratios and 95% confidence intervals were derived from univariate and multivariable conditional logistic models.
  
  
  RESULTS
  A history of maternal previous birth defect-affected pregnancy was a risk factor for NTDs (adjusted OR = 4.00, 95%CI = 1.29-12.45). Risks for NTDs were significantly associated with exposure to maternal factors during the periconceptional period such as a history of fever or cold (adjusted OR = 6.36, 95%CI = 3.24-12.52), use of analgesic and antipyretic drugs (adjusted OR = 4.94, 95%CI = 1.79-13.63), oral contraceptive use (adjusted OR 2.06, 95%CI 1.16, 3.68), and passive smoking (adjusted OR = 2.24, 95%CI = 1.04-4.81). Folic acid tablets use and fresh vegetable or fruit consumption ≥6 meals a week in periconception appeared to be protective factors (adjusted OR 0.33, 0.55, and 0.40, and 95%CI 0.13-0.44, 0.30-1.01, and 0.21-0.74, respectively). Differences in risk were found between the two most common phenotypes of NTD, anencephaly, and spina bifida.
  
  
  CONCLUSIONS
  This study suggests that a history of previous birth defect-affected pregnancy, a history of maternal fever or cold, use of analgesics, antipyretics, and oral contraceptives, exposure to passive smoking, folic acid use, and consumption of fresh vegetable and fruit may be associated with NTD risk.
authors.affiliation: Department of Epidemiology, School of Public Health, China Medical University, No. 92 North Second Road, Heping District, Shenyang, Liaoning Province, People's Republic of China.
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Yin
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.forename: Changying
authors.initials: C
authors.lastname: Xu
authors.forename: Shiqi
authors.initials: S
authors.lastname: Zhang
authors.forename: Yajun
authors.initials: Y
authors.lastname: Zheng
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Baosen
authors.initials: B
authors.lastname: Zhou
mesh_terms: D000700:Analgesics / Q000009:adverse effects; D058633:Antipyretics / Q000009:adverse effects; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D003276:Contraceptives, Oral / Q000009:adverse effects; D004032:Diet / Q000009:adverse effects; D005260:Female; D005492:Folic Acid / Q000009:adverse effects; D006801:Humans; D009436:Neural Tube Defects / Q000453:epidemiology* / Q000209:etiology*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*; D015995:Prevalence; D012307:Risk Factors; D014028:Tobacco Smoke Pollution / Q000009:adverse effects
chemical_list: D000700:Analgesics; D058633:Antipyretics; D003276:Contraceptives, Oral; D014028:Tobacco Smoke Pollution; D005492:Folic Acid